1 | //last change: 2007/07/06 (Oliver Labs) |
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2 | /////////////////////////////////////////////////////////////////////////////// |
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3 | version="$Id: surfex.lib,v 1.1 2008-09-23 11:12:53 Singular Exp $"; |
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4 | category="Visualization"; |
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5 | info=" |
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6 | LIBRARY: surfex.lib |
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7 | Procedures for Visualizing Surfaces. |
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8 | This is still an alpha version! Please, send me any comments |
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9 | or suggestions via http://www.AlgebraicSurface.net |
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10 | Thank you!!! |
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11 | AUTHOR: Oliver Labs |
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12 | This library uses the program surfex. |
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13 | surfex is written by Oliver Labs and others, |
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14 | mainly Stephan Holzer. |
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15 | It is based on some other tools, mainly |
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16 | surf which was written by Stefan Endrass and others. |
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17 | Some of the code is based on the code in surf.lib |
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18 | |
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19 | NOTE: |
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20 | Many procedures of this library require the program surfex |
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21 | to be installed. |
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22 | This software is used for producing raytraced images of the surfaces. |
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23 | You can download @code{surfex} from @uref{http://www.surfex.AlgebraicSurface.net}. |
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24 | |
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25 | surfex is a front-end for surf which aims to be easier to use than |
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26 | the original tool. In the future, we plan to extend it to a tool which |
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27 | can use other appropriate programs for producing the best visualization. |
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28 | Please, contact me via @uref{http://www.surfex.AlgebraicSurface.net} |
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29 | if you have any questions or suggestions, |
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30 | |
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31 | Oliver Labs |
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32 | |
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33 | PROCEDURES: |
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34 | proc plotRotated(poly p, list coords, list #) |
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35 | Plot the surface given by the polynomial p |
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36 | with the coordinates coords. |
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37 | proc plotRot(poly p, list #) |
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38 | Similar to plotRotated, but tries to guess automatically |
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39 | which coordinates should be used. |
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40 | proc plotRotatedList(list varieties, list coords, list #); |
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41 | Plot the varieties given by the list varieties |
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42 | with the coordinates coords. |
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43 | proc plotRotatedDirect(list varietiesList, list #); |
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44 | Plot the varieties given by the list varietiesList. |
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45 | varietiesList has a complicated format. |
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46 | The procedure passes the data directly to surfex. |
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47 | Thus, the coordinates have to be x,y,z. |
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48 | Parameters are allowed; their names have to be p1, p2, ... |
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49 | proc plotRotatedListFromSpecifyList(list varietiesList, list #) ; |
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50 | Plot the varieties given by the list varietiesList. |
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51 | varietiesList has a complicated format; see the example. |
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52 | "; |
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53 | |
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54 | LIB "solve.lib"; |
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55 | LIB "primdec.lib"; |
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56 | LIB "sing.lib"; |
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57 | |
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58 | /////////////////////////////////////////////////////////// |
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59 | // |
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60 | // the main procedures: |
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61 | // |
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62 | |
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63 | proc plotRot(poly p, list #) |
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64 | " |
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65 | USAGE: plotRot(poly p, list #) |
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66 | Similar to plotRotated, but tries to guess automatically |
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67 | which coordinates should be used. |
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68 | |
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69 | It opens the external program surfex for drawing the surface given by p, |
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70 | seen as a surface in the real affine space with coordinates coords. |
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71 | |
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72 | RETURN: the return code of the system command which executes surfex. |
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73 | |
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74 | ASSUME: The basering is characteristic zero and without parameters. |
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75 | " |
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76 | { |
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77 | list coords = list(); |
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78 | if(num_vars_id(p)==3) { |
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79 | execute("coords = "+string_of_vars(p)+";"); |
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80 | } else { |
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81 | if(num_vars_id(p)<3) { |
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82 | if(nvars(basering)==3) { |
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83 | execute("coords = "+varstr(basering)+";"); |
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84 | } else { |
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85 | if(nvars(basering)<3) { |
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86 | "Could not guess the coordinates because the number of variables in the basering is smaller than 3!"; |
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87 | "Please use plotRotated() instead of plotRot() and specify the coordinates explicitly."; |
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88 | return(0); |
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89 | } else { |
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90 | "Could not guess the coordinates because the number of variables in the polynomial is smaller than 3 and the number of variables in the basering is greater than three!"; |
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91 | "Please use plotRotated() instead of plotRot() and specify the coordinates explicitly."; |
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92 | return(0); |
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93 | } |
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94 | } |
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95 | } else { |
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96 | "Could not guess the coordinates because the number of variables in the polynomial is greater than 3!"; |
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97 | "Please use plotRotated() instead of plotRot() and specify the coordinates explicitly."; |
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98 | return(0); |
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99 | } |
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100 | } |
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101 | return(plotRotatedList(list(p), coords, #)); |
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102 | } |
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103 | example { |
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104 | "Example:"; echo=2; |
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105 | |
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106 | // More variables in the basering, but only 3 variables in the polynomial: |
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107 | ring r1 = 0, (w,x,y,z), dp; |
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108 | poly cayley_cubic = x^3+y^3+z^3+1^3-1/4*(x+y+z+1)^3; |
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109 | plotRot(cayley_cubic); |
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110 | |
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111 | // Three variables in the basering, but fewer variables in the polynomial: |
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112 | ring r2 = 0, (x,y,z), dp; |
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113 | plotRot(x^2+y^2-1); |
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114 | plotRot(y^2+z^2-1); |
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115 | |
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116 | // A cubic surface with a solitary point: |
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117 | // Use the additional parameter 3 to ask singular |
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118 | // to compute the singular locus before calling surfex. |
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119 | ring r3 = 0, (x,y,z), dp; |
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120 | poly kn_10 = x^3-3*x*y^2+z^3+3*x^2+3*y^2+z^2; |
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121 | plotRot(kn_10, 3); |
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122 | |
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123 | // The swallowtail: |
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124 | // a surface with a real solitary curve sticking out of the surface. |
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125 | // Use the additional parameter 3 to ask singular |
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126 | // to compute the singular locus before calling surfex. |
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127 | poly swallowtail = -4*y^2*z^3-16*x*z^4+27*y^4+144*x*y^2*z+128*x^2*z^2-256*x^3; |
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128 | plotRot(swallowtail, 3); |
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129 | } |
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130 | |
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131 | proc plotRotated(poly p, list coords, list #) |
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132 | " |
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133 | USAGE: plotRotated(poly p, list coords, list #) |
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134 | This opens the external program surfex for drawing the surface given by p, |
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135 | seen as a surface in the real affine space with coordinates coords. |
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136 | |
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137 | RETURN: the return code of the system command which executes surfex. |
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138 | |
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139 | ASSUME: coords is a list of three variables. |
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140 | The basering is characteristic zero and without parameters. |
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141 | " |
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142 | { |
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143 | return(plotRotatedList(list(p), coords, #)); |
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144 | } |
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145 | example { |
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146 | "Example:"; echo=2; |
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147 | |
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148 | // An easy example: a surface with four conical nodes. |
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149 | ring r = 0, (x,y,z), dp; |
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150 | poly cayley_cubic = x^3+y^3+z^3+1^3-1/4*(x+y+z+1)^3; |
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151 | // plotRotated(cayley_cubic, list(x,y,z)); |
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152 | |
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153 | // An difficult example: a surface with a one-dimensional real component! |
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154 | poly whitney_umbrella = x^2*z-y^2; |
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155 | // The Whitney Umbrella without its handle: |
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156 | plotRotated(whitney_umbrella, list(x,y,z)); |
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157 | // The Whitney Umbrella together with its handle: |
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158 | plotRotated(whitney_umbrella, list(x,y,z), 2); |
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159 | } |
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160 | |
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161 | |
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162 | proc plotRotatedList(list varieties, list coords, list #) |
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163 | " |
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164 | USAGE: plotRotatedList(list varieties, list coords, list #) |
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165 | This opens the external program surfex for drawing the surfaces given by varieties, |
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166 | seen as a surface in the real affine space with coordinates coords. |
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167 | |
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168 | RETURN: the return code of the system command which executes surfex. |
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169 | |
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170 | ASSUME: coords is a list of three variables, |
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171 | varieties is a list of ideals discribing the varieties to be shown. |
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172 | The basering is characteristic zero and without parameters. |
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173 | " |
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174 | { |
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175 | def oring = basering; |
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176 | |
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177 | int plotquality = 0; |
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178 | if(size(#)>0) { |
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179 | plotquality = #[1]; |
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180 | } |
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181 | |
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182 | list varietiesList = list(list(), list(), list(), list()); |
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183 | list usedSurfaces = list(); |
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184 | list curveColors = list(); |
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185 | |
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186 | // go through the list of varieties |
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187 | // produce a list which can be used as input for plotRotatedListFromList() |
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188 | int i; |
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189 | int j; |
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190 | list indList; |
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191 | int ind; |
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192 | ideal itmp; |
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193 | int ncurves; |
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194 | list pd; |
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195 | int k; |
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196 | int surfind; |
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197 | list curSurfColors = list(); |
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198 | |
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199 | list listOfPoints = list(); |
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200 | string str_I = ""; |
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201 | |
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202 | for(i=1; i<=size(varieties); i++) { |
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203 | itmp = varieties[i]; |
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204 | if(plotquality>=3) { |
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205 | itmp = radical(itmp); |
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206 | } |
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207 | itmp = simplify(itmp,1); |
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208 | itmp = simplify(itmp,2); |
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209 | if(size(itmp)==1) { // i.e.: a surface given by one equation |
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210 | surfind = findInList(surfEqn(itmp[1],coords), usedSurfaces); |
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211 | if(surfind==0) { |
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212 | usedSurfaces = usedSurfaces + list(surfEqn(itmp[1],coords)); |
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213 | curSurfColors = list(list("insidecolor:",getInsideColorStr(size(varietiesList[1])+1)), |
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214 | list("outsidecolor:",getOutsideColorStr(size(varietiesList[1])+1))); |
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215 | varietiesList[1] = varietiesList[1] + |
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216 | list(list(list("eqno:",string(size(varietiesList[1])+1)), |
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217 | list("equation:",surfEqn(itmp[1], coords)), |
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218 | curSurfColors[1], |
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219 | curSurfColors[2], |
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220 | list("showcbox:","true"), |
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221 | list("transparency:","0"))); |
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222 | surfind = size(varietiesList[1]); |
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223 | |
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224 | } |
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225 | if(plotquality==1) { |
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226 | varieties = varieties + list(slocus(itmp[1])); |
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227 | } |
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228 | if(plotquality==2 || plotquality==3) { |
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229 | // remove doubled components and |
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230 | // add the 1-dimensional singular components |
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231 | // of the surface to the list of curves: |
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232 | int dsl = dim_slocus(itmp[1]); |
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233 | dsl; |
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234 | if(dsl>=0) { // i.e. there is a singular locus |
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235 | "compute singular locus..."; |
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236 | list eqd; |
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237 | // |
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238 | eqd = equidim(slocus(itmp[1])); |
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239 | ideal tmp_l; |
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240 | tmp_l = std(eqd[size(eqd)]); |
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241 | "dim:",dim(tmp_l); |
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242 | if(dim(tmp_l)==(nvars(basering)-3+2)) { |
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243 | "--- 2-dim."; |
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244 | // we have found a multiple component; |
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245 | // replace it by a simple copy of it |
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246 | itmp = quotient(itmp[1], tmp_l); |
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247 | varieties[i] = itmp[1]; |
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248 | eqd = delete(eqd,size(eqd)); |
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249 | if(size(eqd)>0) { |
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250 | tmp_l = std(eqd[size(eqd)]); |
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251 | } |
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252 | } |
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253 | if(dim(tmp_l)==(nvars(basering)-3+1)) { |
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254 | "--- 1-dim."; |
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255 | // we have found a 1-dimensional singular locus |
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256 | pd = std_primdecGTZ(tmp_l,2); |
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257 | for(k=1; k<=size(pd); k++) { |
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258 | if(pd[k][3]==(nvars(basering)-3+1)) { |
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259 | varieties = varieties + list(pd[k][2]); |
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260 | curveColors[size(varieties)] = curSurfColors; |
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261 | } else { |
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262 | "???"; |
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263 | } |
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264 | } |
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265 | eqd = delete(eqd,size(eqd)); |
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266 | if(size(eqd)>0) { |
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267 | tmp_l = std(eqd[size(eqd)]); |
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268 | } |
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269 | } |
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270 | if(dim(tmp_l)==(nvars(basering)-3+0)) { |
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271 | "--- 0-dim."; |
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272 | // we have found a 0-dimensional singular locus |
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273 | // we compute floating point approximations of the |
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274 | // coordinates of all singular points |
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275 | if(npars(oring)>0) { |
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276 | "str:",parstr(1),rootminpoly(); |
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277 | list all_real_sols = allroots_minpoly(); |
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278 | // "all sols:";all_real_sols; |
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279 | // sprintf("number %s = %s; ", parstr(1), rootminpoly()); |
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280 | int minp; |
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281 | if((npars(basering) == 1) && (minpoly != 0)) { |
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282 | minp = 1; |
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283 | } else { |
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284 | minp = 0; |
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285 | } |
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286 | str_I = ""; |
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287 | if(minp==1) { |
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288 | "minp=1"; |
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289 | string str_para = parstr(1); |
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290 | string str_tmp_l; |
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291 | def cur_ring = basering; |
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292 | if(1) { |
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293 | short=0; |
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294 | str_tmp_l = "ideal eqd_tmp = "+ |
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295 | // string(tmp_l)+","+string(minpoly)+";"; |
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296 | string(tmp_l); |
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297 | "str:",str_tmp_l; |
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298 | string str_num_mp = "number "+parstr(1)+"="+ |
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299 | decstr2ratstr(rootminpoly())+";"; |
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300 | execute("ring Iring = 0,(" |
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301 | // +string(coords)+","+str_para+"),dp;"); |
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302 | +string(coords)+"),dp;"); |
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303 | basering; |
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304 | execute(str_num_mp); |
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305 | execute(str_tmp_l); |
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306 | eqd_tmp; |
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307 | list real_sols = real_solve(eqd_tmp); |
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308 | real_sols; |
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309 | $; |
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310 | setring cur_ring; |
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311 | } |
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312 | } else { |
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313 | // minp==0: we do not know how to handle this |
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314 | "???"; |
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315 | } |
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316 | } else { |
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317 | "no pars"; |
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318 | ideal eqd_tmp = tmp_l; |
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319 | short=0; |
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320 | string str_tmp_l = "ideal eqd_tmp = "+string(tmp_l)+";"; |
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321 | def cur_ring = basering; |
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322 | execute("ring Iring = (real,30),("+string(coords)+"),("+ordstr(oring)+");"); |
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323 | // basering; |
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324 | execute(str_I); |
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325 | execute(str_tmp_l); |
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326 | list real_sols = real_solve(eqd_tmp); |
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327 | setring cur_ring; |
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328 | } |
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329 | "real_sols:";real_sols; |
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330 | for(k=1; k<=size(real_sols); k++) { |
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331 | "search point:"; |
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332 | string(list(real_sols[k][1],real_sols[k][2],real_sols[k][3],string(surfind))); |
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333 | // listOfPoints; |
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334 | if(findInList(string(list(list(real_sols[k][1],real_sols[k][2],real_sols[k][3],string(surfind)))), |
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335 | listOfPoints)==0) { |
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336 | "add pt"; |
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337 | varietiesList[4] = varietiesList[4] + |
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338 | list(list(real_sols[k][1],real_sols[k][2],real_sols[k][3],string(surfind))); |
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339 | listOfPoints = listOfPoints + |
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340 | list(string(list(real_sols[k][1],real_sols[k][2],real_sols[k][3],string(surfind)))); |
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341 | } |
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342 | } |
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343 | } |
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344 | } |
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345 | } |
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346 | } else { |
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347 | // i.e.: more than one equation |
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348 | varietiesList[2] = varietiesList[2] + |
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349 | list(list(list("surfaces:"), |
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350 | list("curveno:", |
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351 | string(size(varietiesList[2])+1)), |
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352 | list("showcbox:","true"))); |
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353 | if(size(curveColors) >= i) { |
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354 | varietiesList[2][size(varietiesList[2])][4] = curveColors[i][1]; |
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355 | varietiesList[2][size(varietiesList[2])][4][1] = "color:"; |
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356 | } |
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357 | ncurves = size(varietiesList[2]); |
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358 | for(j=1; j<=size(itmp); j++) { |
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359 | ind = findInList(surfEqn(itmp[j],coords), usedSurfaces); |
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360 | usedSurfaces = usedSurfaces + list(surfEqn(itmp[1],coords)); |
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361 | // "indList:";indList; |
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362 | if(ind == 0) { |
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363 | // "--------> not in list", surfEqn(itmp[j], coords); |
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364 | if(j==1) { |
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365 | varietiesList[1] = varietiesList[1] + |
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366 | list(list(list("eqno:",string(size(varietiesList[1])+1)), |
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367 | list("equation:",surfEqn(itmp[j], coords)), |
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368 | list("insidecolor:",getInsideColorStr(size(varietiesList[1])+1)), |
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369 | list("outsidecolor:",getOutsideColorStr(size(varietiesList[1])+1)), |
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370 | list("showcbox:","true"), |
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371 | list("transparency:","100"))); |
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372 | } else { |
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373 | varietiesList[1] = varietiesList[1] + |
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374 | list(list(list("eqno:",string(size(varietiesList[1])+1)), |
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375 | list("equation:",surfEqn(itmp[j], coords)), |
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376 | list("insidecolor:",getInsideColorStr(size(varietiesList[1])+1)), |
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377 | list("outsidecolor:",getOutsideColorStr(size(varietiesList[1])+1)), |
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378 | list("showcbox:","false"), |
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379 | list("transparency:","0"))); |
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380 | } |
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381 | ind = size(varietiesList[1]); |
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382 | } else { |
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383 | } |
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384 | varietiesList[2][ncurves][1] = varietiesList[2][ncurves][1] + list(string(ind)); |
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385 | } |
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386 | } |
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387 | } |
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388 | |
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389 | // "------------"; |
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390 | // varietiesList; |
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391 | // "------------"; |
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392 | return(plotRotatedListFromSpecifyList(varietiesList, coords, #)); |
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393 | } |
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394 | example { |
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395 | "Example:"; echo=2; |
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396 | |
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397 | // A cubic surface together with a tritangent plane |
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398 | // (i.e. a plane which cuts out three lines). |
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399 | ring r = 0, (x,y,z), dp; |
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400 | poly cayley_cubic = x^3+y^3+z^3+1^3-1/4*(x+y+z+1)^3; |
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401 | poly plane = 1-x-y-z; |
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402 | plotRotatedList(list(cayley_cubic, plane), list(x,y,z)); |
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403 | |
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404 | // The same cubic and plane. |
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405 | // The plane is not shown but only its intersection with the surface. |
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406 | plotRotatedList(list(cayley_cubic, ideal(cayley_cubic, plane)), list(x,y,z)); |
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407 | } |
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408 | |
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409 | |
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410 | proc plotRotatedListFromSpecifyList(list varietiesList, list #) |
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411 | " |
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412 | USAGE: plotRotatedListFromSpecifyList(list varietiesList, list #); |
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413 | varietiesList has a complicated format (not documented yet); |
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414 | see the example. |
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415 | |
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416 | RETURN: the return code of the system command which executes surfex. |
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417 | |
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418 | ASSUME: The basering is characteristic zero. |
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419 | |
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420 | EXAMPLE: example plotRotatedListFromSpecifyList; |
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421 | " |
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422 | { |
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423 | // make the surfex file |
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424 | string str = getSurfexCodeFromSpecifyList(varietiesList, #); |
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425 | |
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426 | return(plotRotatedFromCode(str, #)); |
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427 | } |
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428 | example { |
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429 | "Example:"; echo=2; |
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430 | |
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431 | // A cubic surface depending on a parameter: |
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432 | ring r = (0,p1), (x,y,z), dp; |
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433 | poly cayley_cubic = x^3+y^3+z^3+1^3-p1*(x+y+z+1)^3; |
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434 | poly plane = 1-x-y-z; |
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435 | plotRotatedListFromSpecifyList(list(list(list(list("eqno:","1"), |
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436 | list("equation:", |
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437 | string(cayley_cubic)) |
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438 | ) |
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439 | ), |
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440 | list(), |
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441 | list(list(1,"0.0","1.0","500","0.25+0.25*sin(PI*p1)")), |
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442 | list() |
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443 | )); |
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444 | } |
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445 | |
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446 | |
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447 | proc plotRotatedListFromStringList(list varieties, list #) |
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448 | " |
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449 | RETURN: the return code of the system command which executes surfex. |
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450 | |
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451 | USAGE: not documented yet. |
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452 | " |
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453 | { |
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454 | // make the surfex file |
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455 | getSurfexCodeFromStringList(varieties, #); |
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456 | string str = getSurfexCodeFromStringList(varieties, #); |
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457 | |
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458 | return(plotRotatedFromCode(str, #)); |
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459 | } |
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460 | |
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461 | |
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462 | proc plotRotatedDirect(list varieties, list #) |
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463 | " |
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464 | USAGE: plotRotatedDirect(list varieties, list #) |
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465 | This opens the external program surfex for drawing the surfaces given by varieties, |
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466 | seen as a surface in the real affine space with coordinates x,y,z. |
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467 | The format for the list varieties is not fully documented yet; |
---|
468 | please, try to adapt the examples to your needs. |
---|
469 | |
---|
470 | RETURN: the return code of the system command which executes surfex. |
---|
471 | |
---|
472 | ASSUME: |
---|
473 | Passes the equations directly to surfex, |
---|
474 | i.e., the variable names should be correct, i.e. x,y,z. |
---|
475 | The advantage is that one can use parameters p1, p2, ...; |
---|
476 | these will be passed to surfex. |
---|
477 | " |
---|
478 | { |
---|
479 | string str = getSurfexCodeFromListDirect(varieties, #); |
---|
480 | |
---|
481 | return(plotRotatedFromCode(str, #)); |
---|
482 | } |
---|
483 | example { |
---|
484 | "Example:"; echo=2; |
---|
485 | |
---|
486 | // A cubic surface depending on a parameter: |
---|
487 | ring r = (0,p1), (x,y,z), dp; |
---|
488 | poly cayley_cubic = x^3+y^3+z^3+1^3-p1*(x+y+z+1)^3; |
---|
489 | // The entries of the list of varieties can either be polynomials |
---|
490 | plotRotatedDirect(list(list(list(cayley_cubic)), |
---|
491 | list(), |
---|
492 | list(list(1,"0.0","1.0","500","0.25+0.25*sin(PI*p1)")) |
---|
493 | )); |
---|
494 | |
---|
495 | // or strings which represent surfex-readable polynomials |
---|
496 | plotRotatedDirect(list(list(list("x^3+y^3+z^3+1^3-p1*(x+y+z+1)^3")), |
---|
497 | list(), |
---|
498 | list(list("1","0.0","1.0","500","0.25+0.25*sin(PI*p1)")) |
---|
499 | )); |
---|
500 | |
---|
501 | // More complicated varieties |
---|
502 | plotRotatedDirect(list(list(list("x^2+y^2-z^2-3^2"), |
---|
503 | list("x*sin(p1)+y*cos(p1)-3")), |
---|
504 | list(list(list(1,2))), |
---|
505 | list(list("1","0.0","1.0","500","2*PI*p1")) |
---|
506 | )); |
---|
507 | } |
---|
508 | |
---|
509 | proc plotRotatedFromCode(string str, list #) |
---|
510 | " |
---|
511 | USAGE: plotRotatedFromCode(string str, list #); |
---|
512 | |
---|
513 | This procedure is only for internal usage; |
---|
514 | it takes the surfex-code as a string and calls surfex. |
---|
515 | |
---|
516 | RETURN: the return code of the system command which executes surfex. |
---|
517 | " |
---|
518 | { |
---|
519 | // we need a temporary .sux file for surfex |
---|
520 | string tmpd = "/tmp"; |
---|
521 | string l="surf"+string(system("pid"))+".sux"; |
---|
522 | // a temporary file which stores the output of surfex |
---|
523 | string erg="/tmp/surferg"+string(system("pid")); |
---|
524 | |
---|
525 | write(":w "+tmpd+"/"+l, str); |
---|
526 | |
---|
527 | int i=system("sh","surfex -d "+tmpd+" -i " + l +" >"+erg+" 2>/dev/null"); |
---|
528 | |
---|
529 | // delete the temporary file |
---|
530 | i = system("sh","rm " + l +" 2>/dev/null"); |
---|
531 | return(read(erg)); |
---|
532 | } |
---|
533 | |
---|
534 | |
---|
535 | /////////////////////////////////////////////////////////// |
---|
536 | // |
---|
537 | // procedures used to produce the surf-code: |
---|
538 | // |
---|
539 | |
---|
540 | |
---|
541 | proc getSurfexCodeFromListDirect(list varieties, list #) |
---|
542 | " |
---|
543 | USAGE: getSurfexCodeFromListDirect(list varieties, list #) |
---|
544 | |
---|
545 | ASSUME: varieties has four components, |
---|
546 | - the first is a list of polynomials, say f_1, ..., f_k |
---|
547 | - the second is a list of lists of numbers in {1, ..., k} describing the curves |
---|
548 | as intersections of the corresponding f_i |
---|
549 | - the third is a list of lists describing the parameters used in the polynomials f_i |
---|
550 | - the fourth is a list of lists of points given by their approximate coordinates (three decimal numbers) |
---|
551 | |
---|
552 | RETURN: the surfex code (.sux) |
---|
553 | " |
---|
554 | { |
---|
555 | int i; |
---|
556 | int j; |
---|
557 | string str = "this is surfex v0.89.07"+newline; |
---|
558 | |
---|
559 | str = str + "TYPE:" + newline; |
---|
560 | str = str + "specify"+newline; |
---|
561 | str = str + "EQUATIONS:"+newline; |
---|
562 | str = str + string(size(varieties[1])) + newline; |
---|
563 | for(i=1; i<=size(varieties[1]); i++) { |
---|
564 | str = str + "Equation:"+newline; |
---|
565 | str = str + "eqno:"+newline; |
---|
566 | str = str + string(i) + newline; |
---|
567 | str = str + "equation:"+newline; |
---|
568 | str = str + surfEqnDir(varieties[1][i][1]) + newline; |
---|
569 | if(size(varieties[1][i])>=2) { |
---|
570 | str = str + "showcbox:"+newline; |
---|
571 | str = str + varieties[1][i][2] + newline; // show it or not |
---|
572 | if(size(varieties[1][i])>=3) { |
---|
573 | str = str + "transparency:"+newline; |
---|
574 | str = str + string(varieties[1][i][3]) + newline; // transparency |
---|
575 | } |
---|
576 | } |
---|
577 | } |
---|
578 | str = str + "CURVES:"+newline; |
---|
579 | str = str + string(size(varieties[2])) + newline; |
---|
580 | for(i=1; i<=size(varieties[2]); i++) { |
---|
581 | str = str + "Curve:"+newline; |
---|
582 | str = str + "curveno:"+newline; |
---|
583 | str = str + string(i) + newline; |
---|
584 | str = str + "surfaces:"+newline; |
---|
585 | // "curves:";varieties[2][i]; |
---|
586 | for(j=1; j<=size(varieties[2][i][1]); j++) { |
---|
587 | str = str + string(varieties[2][i][1][j]) + newline; |
---|
588 | } |
---|
589 | if(size(varieties[2][i])>=2) { |
---|
590 | str = str + "showcbox:"+newline; |
---|
591 | str = str + varieties[2][i][2] + newline; // show it or not |
---|
592 | } |
---|
593 | } |
---|
594 | str = str + "PARAMETERS:"+newline; |
---|
595 | str = str + string(size(varieties[3])) + newline; |
---|
596 | for(i=1; i<=size(varieties[3]); i++) { |
---|
597 | str = str + "Parameter:"+newline; |
---|
598 | str = str + "parno:"+newline; |
---|
599 | str = str + string(varieties[3][i][1]) + newline; |
---|
600 | str = str + "fromtoval:"+newline; |
---|
601 | str = str + varieties[3][i][2] + newline; |
---|
602 | str = str + varieties[3][i][3] + newline; |
---|
603 | str = str + string(varieties[3][i][4]) + newline; |
---|
604 | if(size(varieties[3][i])>=5) { |
---|
605 | str = str + "function:"+newline; |
---|
606 | str = str + varieties[3][i][5]+newline; |
---|
607 | } |
---|
608 | } |
---|
609 | // str = str + "////////////////// Parameter: /////////////////////////"+newline; |
---|
610 | // str = str + "1" + newline; |
---|
611 | // str = str + "0.0" + newline; |
---|
612 | // str = str + "1.0" + newline; |
---|
613 | // str = str + "1000" + newline; |
---|
614 | // str = str + string(size(varieties[3])) + newline; |
---|
615 | return(str); |
---|
616 | } |
---|
617 | |
---|
618 | proc getSurfexCodeFromList(list varieties, list coords, list #) |
---|
619 | " |
---|
620 | ASSUME: varieties has four components, |
---|
621 | - the first is a list of polynomials, say f_1, ..., f_k |
---|
622 | - the second is a list of lists of numbers in {1, ..., k} describing the curves |
---|
623 | as intersections of the corresponding f_i |
---|
624 | - the third is a list of lists describing the parameters used in the polynomials f_i |
---|
625 | - the fourth is a list of lists of points given by their approximate coordinates (three decimal numbers) |
---|
626 | |
---|
627 | RETURN: the surfex code (.sux) |
---|
628 | " |
---|
629 | { |
---|
630 | int i; |
---|
631 | int j; |
---|
632 | string str = "this is surfex v0.89.07"+newline; |
---|
633 | |
---|
634 | str = str + "TYPE:" + newline; |
---|
635 | str = str + "specify"+newline; |
---|
636 | str = str + "EQUATIONS:"+newline; |
---|
637 | str = str + string(size(varieties[1])) + newline; |
---|
638 | for(i=1; i<=size(varieties[1]); i++) { |
---|
639 | str = str + "Equation:"+newline; |
---|
640 | str = str + "eqno:"+newline; |
---|
641 | str = str + string(i) + newline; |
---|
642 | str = str + "equation:"+newline; |
---|
643 | str = str + surfEqn(varieties[1][i][1], coords) + newline; |
---|
644 | str = str + "showcbox:"+newline; |
---|
645 | str = str + varieties[1][i][2] + newline; // show it or not |
---|
646 | str = str + "transparency:"+newline; |
---|
647 | str = str + string(varieties[1][i][3]) + newline; // transparency |
---|
648 | } |
---|
649 | str = str + "CURVES:"+newline; |
---|
650 | str = str + string(size(varieties[2])) + newline; |
---|
651 | for(i=1; i<=size(varieties[2]); i++) { |
---|
652 | str = str + "Curve:"+newline; |
---|
653 | str = str + "curveno:"+newline; |
---|
654 | str = str + string(i) + newline; |
---|
655 | str = str + "surfaces:"+newline; |
---|
656 | for(j=1; j<=size(varieties[2][i]); j++) { |
---|
657 | str = str + string(varieties[2][i][1][j]) + newline; |
---|
658 | } |
---|
659 | str = str + "showcbox:"+newline; |
---|
660 | str = str + varieties[2][i][2] + newline; // show it or not |
---|
661 | } |
---|
662 | str = str + "PARAMETERS:"+newline; |
---|
663 | str = str + string(size(varieties[3])) + newline; |
---|
664 | for(i=1; i<=size(varieties[3]); i++) { |
---|
665 | str = str + "Parameter:"+newline; |
---|
666 | str = str + "parno:"+newline; |
---|
667 | str = str + string(varieties[3][i][1]) + newline; |
---|
668 | str = str + "fromtoval:"+newline; |
---|
669 | str = str + surfEqn(varieties[3][i][2], coords) + newline; |
---|
670 | str = str + surfEqn(varieties[3][i][3], coords) + newline; |
---|
671 | str = str + string(varieties[3][i][4]) + newline; |
---|
672 | if(size(varieties[3][i])>=5) { |
---|
673 | str = str + "function:"+newline; |
---|
674 | str = str + varieties[3][i][5]+newline; |
---|
675 | } |
---|
676 | } |
---|
677 | // str = str + "////////////////// Parameter: /////////////////////////"+newline; |
---|
678 | // str = str + "1" + newline; |
---|
679 | // str = str + "0.0" + newline; |
---|
680 | // str = str + "1.0" + newline; |
---|
681 | // str = str + "1000" + newline; |
---|
682 | // str = str + string(size(varieties[3])) + newline; |
---|
683 | return(str); |
---|
684 | } |
---|
685 | |
---|
686 | proc getSurfexCodeFromStringList(list varieties, list #) |
---|
687 | " |
---|
688 | ASSUME: varieties has three components, |
---|
689 | - the first is a list of polynomials, say f_1, ..., f_k |
---|
690 | - the second is a list of lists of numbers in {1, ..., k} describing the curves |
---|
691 | as intersections of the corresponding f_i |
---|
692 | - the third is a list of lists describing the parameters used in the polynomials f_i |
---|
693 | |
---|
694 | RETURN: the surfex code (.sux) |
---|
695 | " |
---|
696 | { |
---|
697 | int i; |
---|
698 | int j; |
---|
699 | string str = "this is surfex v0.89.07"+newline; |
---|
700 | |
---|
701 | str = str + "TYPE:" + newline; |
---|
702 | str = str + "specify"+newline; |
---|
703 | str = str + "EQUATIONS:"+newline; |
---|
704 | str = str + string(size(varieties[1])) + newline; |
---|
705 | for(i=1; i<=size(varieties[1]); i++) { |
---|
706 | str = str + "Equation:"+newline; |
---|
707 | str = str + "eqno:"+newline; |
---|
708 | str = str + string(i) + newline; |
---|
709 | str = str + "equation:"+newline; |
---|
710 | str = str + varieties[1][i][1] + newline; |
---|
711 | str = str + "showcbox:"+newline; |
---|
712 | str = str + varieties[1][i][2] + newline; // show it or not |
---|
713 | str = str + "transparency:"+newline; |
---|
714 | str = str + varieties[1][i][3] + newline; // transparency |
---|
715 | } |
---|
716 | str = str + "CURVES:"+newline; |
---|
717 | str = str + string(size(varieties[2])) + newline; |
---|
718 | for(i=1; i<=size(varieties[2]); i++) { |
---|
719 | str = str + "Curve:"+newline; |
---|
720 | str = str + "curveno:"+newline; |
---|
721 | str = str + string(i) + newline; |
---|
722 | str = str + "surfaces:"+newline; |
---|
723 | for(j=1; j<=size(varieties[2][i][1]); j++) { |
---|
724 | str = str + string(varieties[2][i][1][j]) + newline; |
---|
725 | } |
---|
726 | str = str + "showcbox:"+newline; |
---|
727 | str = str + varieties[2][i][2] + newline; // show it or not |
---|
728 | } |
---|
729 | str = str + "PARAMETERS:"+newline; |
---|
730 | str = str + string(size(varieties[3])) + newline; |
---|
731 | for(i=1; i<=size(varieties[3]); i++) { |
---|
732 | str = str + "Parameter:"+newline; |
---|
733 | str = str + "parno:"+newline; |
---|
734 | str = str + string(varieties[3][i][1]) + newline; |
---|
735 | str = str + "fromtoval:"+newline; |
---|
736 | str = str + varieties[3][i][2] + newline; |
---|
737 | str = str + varieties[3][i][3] + newline; |
---|
738 | str = str + string(varieties[3][i][4]) + newline; |
---|
739 | if(size(varieties[3][i])>=5) { |
---|
740 | str = str + "function:"+newline; |
---|
741 | str = str + varieties[3][i][5]+newline; |
---|
742 | } |
---|
743 | } |
---|
744 | return(str); |
---|
745 | } |
---|
746 | |
---|
747 | |
---|
748 | proc getSurfexCodeFromSpecifyList(list varieties, list #) |
---|
749 | " |
---|
750 | ASSUME: varieties has three components, |
---|
751 | - the first is a list of polynomials, say f_1, ..., f_k |
---|
752 | - the second is a list of lists of numbers in {1, ..., k} describing the curves |
---|
753 | as intersections of the corresponding f_i |
---|
754 | - the third is a list of lists describing the parameters used in the polynomials f_i |
---|
755 | - the fourth is a list of lists describing the singular points to be shown as spheres |
---|
756 | |
---|
757 | RETURN: the surfex code (.sux) |
---|
758 | " |
---|
759 | { |
---|
760 | int i; |
---|
761 | int j; |
---|
762 | int k; |
---|
763 | string str = "this is surfex v0.89.07"+newline; |
---|
764 | |
---|
765 | str = str + "TYPE:" + newline; |
---|
766 | str = str + "specify"+newline; |
---|
767 | str = str + "EQUATIONS:"+newline; |
---|
768 | str = str + string(size(varieties[1])) + newline; |
---|
769 | for(i=1; i<=size(varieties[1]); i++) { |
---|
770 | str = str + "Equation:"+newline; |
---|
771 | for(j=1; j<=size(varieties[1][i]); j++) { |
---|
772 | str = str + varieties[1][i][j][1] +newline; |
---|
773 | str = str + varieties[1][i][j][2] +newline; |
---|
774 | } |
---|
775 | } |
---|
776 | str = str + "CURVES:"+newline; |
---|
777 | str = str + string(size(varieties[2])) + newline; |
---|
778 | for(i=1; i<=size(varieties[2]); i++) { |
---|
779 | str = str + "Curve:"+newline; |
---|
780 | for(j=1; j<=size(varieties[2][i]); j++) { |
---|
781 | str = str + varieties[2][i][j][1] +newline; |
---|
782 | if(varieties[2][i][j][1] == "surfaces:") { |
---|
783 | for(k=2; k<=size(varieties[2][i][j]); k++) { |
---|
784 | str = str + string(varieties[2][i][j][k]) + newline; |
---|
785 | } |
---|
786 | } else { |
---|
787 | str = str + varieties[2][i][j][2] +newline; |
---|
788 | } |
---|
789 | } |
---|
790 | // str = str + "curveno:"+newline; |
---|
791 | // str = str + string(i) + newline; |
---|
792 | // str = str + "surfaces:"+newline; |
---|
793 | // for(j=1; j<=size(varieties[2][i][1]); j++) { |
---|
794 | // str = str + string(varieties[2][i][1][j]) + newline; |
---|
795 | // } |
---|
796 | // str = str + "showcbox:"+newline; |
---|
797 | // str = str + varieties[2][i][2] + newline; // show it or not |
---|
798 | } |
---|
799 | str = str + "PARAMETERS:"+newline; |
---|
800 | str = str + string(size(varieties[3])) + newline; |
---|
801 | for(i=1; i<=size(varieties[3]); i++) { |
---|
802 | str = str + "Parameter:"+newline; |
---|
803 | str = str + "parno:"+newline; |
---|
804 | str = str + string(varieties[3][i][1]) + newline; |
---|
805 | str = str + "fromtoval:"+newline; |
---|
806 | str = str + varieties[3][i][2] + newline; |
---|
807 | str = str + varieties[3][i][3] + newline; |
---|
808 | str = str + string(varieties[3][i][4]) + newline; |
---|
809 | if(size(varieties[3][i])>=5) { |
---|
810 | str = str + "function:"+newline; |
---|
811 | str = str + varieties[3][i][5]+newline; |
---|
812 | } |
---|
813 | } |
---|
814 | string str_from = "0.0"; |
---|
815 | string str_to = "5.0"; |
---|
816 | string str_radius = "50"; |
---|
817 | str = str + "SOLITARY POINTS:"+newline; |
---|
818 | str = str + string(size(varieties[4])) + newline; |
---|
819 | for(i=1; i<=size(varieties[4]); i++) { |
---|
820 | str = str + "SolitaryPoint:"+newline; |
---|
821 | str = str + "solPtNo:"+newline; |
---|
822 | str = str + string(i) + newline; |
---|
823 | str = str + "surface:"+newline; |
---|
824 | str = str + varieties[4][i][4] + newline; |
---|
825 | str = str + "fromtoval:"+newline; |
---|
826 | str = str + str_from + newline; |
---|
827 | str = str + str_to + newline; |
---|
828 | str = str + str_radius + newline; |
---|
829 | str = str + "coords:" + newline; |
---|
830 | str = str + varieties[4][i][1] + newline; |
---|
831 | str = str + varieties[4][i][2] + newline; |
---|
832 | str = str + varieties[4][i][3] + newline; |
---|
833 | } |
---|
834 | return(str); |
---|
835 | } |
---|
836 | |
---|
837 | /////////////////////////////////////////////////////////// |
---|
838 | // |
---|
839 | // procedures for standard colors: |
---|
840 | // |
---|
841 | |
---|
842 | proc numBaseColors() |
---|
843 | " |
---|
844 | USAGE: numBaseColors() |
---|
845 | |
---|
846 | RETURN: the number of predefined surface colors. |
---|
847 | " |
---|
848 | { |
---|
849 | return(6); |
---|
850 | } |
---|
851 | |
---|
852 | proc baseSurfaceColors(int no) |
---|
853 | " |
---|
854 | USAGE: baseSurfaceColors(int no) |
---|
855 | |
---|
856 | REMARK: There are currently 6=numBaseColors() basic surface colors. |
---|
857 | You can modify them according to your wishes |
---|
858 | by just redefining this procedure in your Singular-script. |
---|
859 | |
---|
860 | If you want more colors, then you also have to redefine numBaseColors() accordingly. |
---|
861 | |
---|
862 | RETURN: a list of three integers describing the RGB values of a color. |
---|
863 | " |
---|
864 | { |
---|
865 | if(no%numBaseColors()==1) { |
---|
866 | return(list(240,160,0)); |
---|
867 | } |
---|
868 | if(no%numBaseColors()==2) { |
---|
869 | return(list(160,240,0)); |
---|
870 | } |
---|
871 | if(no%numBaseColors()==3) { |
---|
872 | return(list(0,160,240)); |
---|
873 | } |
---|
874 | if(no%numBaseColors()==4) { |
---|
875 | return(list(240,0,160)); |
---|
876 | } |
---|
877 | if(no%numBaseColors()==5) { |
---|
878 | return(list(0,240,160)); |
---|
879 | } |
---|
880 | if(no%numBaseColors()==0) { |
---|
881 | return(list(160,0,240)); |
---|
882 | } |
---|
883 | } |
---|
884 | |
---|
885 | proc getInsideColorStr(int no) |
---|
886 | " |
---|
887 | USAGE: getInsideColorStr(int no) |
---|
888 | |
---|
889 | RETURN: a string describing inside color number no |
---|
890 | where the three integer RGB values are in one line each. |
---|
891 | " |
---|
892 | { |
---|
893 | list bc = baseSurfaceColors(no); |
---|
894 | string str = string(bc[1])+newline+string(bc[2])+newline+string(bc[3]); |
---|
895 | return(str); |
---|
896 | } |
---|
897 | |
---|
898 | proc getOutsideColorStr(int no) |
---|
899 | " |
---|
900 | USAGE: getOutsideColorStr(int no) |
---|
901 | |
---|
902 | RETURN: a string describing outside color number no |
---|
903 | where the three integer RGB values are in one line each. |
---|
904 | " |
---|
905 | { |
---|
906 | list bc = baseSurfaceColors(no); |
---|
907 | string str = string(bc[1])+newline+string(bc[2])+newline+string(bc[3]); |
---|
908 | return(str); |
---|
909 | } |
---|
910 | |
---|
911 | /////////////////////////////////////////////////////////// |
---|
912 | // |
---|
913 | // procedures used by the plot procedures: |
---|
914 | // |
---|
915 | |
---|
916 | proc surfEqnDir(list #) |
---|
917 | " |
---|
918 | USAGE: surfEqnDir(list #) without any checks etc. |
---|
919 | |
---|
920 | RETURN: string(#[1]) where short=0. |
---|
921 | " |
---|
922 | { |
---|
923 | int stmp = short; short = 0; |
---|
924 | string str = string(#[1]); |
---|
925 | short = stmp; |
---|
926 | return(str); |
---|
927 | } |
---|
928 | |
---|
929 | proc surfEqn(poly p, list coords, list #) |
---|
930 | " |
---|
931 | USAGE: surfEqn(poly p, list coords) |
---|
932 | Tries to produce a string for the equation of p which is convenient for surfex. |
---|
933 | ASSUME: - p defines a plane curve or a surface, |
---|
934 | - coords is a list of the three coordinates to use, e.g. list(x,y,z), |
---|
935 | in this way, it is possible to distinguish between x^2+y^2-1 and y^2+z^2-1 |
---|
936 | RETURN: a string, that one can use with the external program surf |
---|
937 | EXAMPLE: example surfEqn; shows an example |
---|
938 | " |
---|
939 | { |
---|
940 | int params=0; |
---|
941 | if(size(#)>0) { |
---|
942 | params = #[1]; |
---|
943 | } |
---|
944 | string err_mes; // string containing error messages |
---|
945 | def base=basering; |
---|
946 | int mynvars = nvars(basering); |
---|
947 | |
---|
948 | intvec ind=num_of_vars(p); |
---|
949 | |
---|
950 | int i,j,n; |
---|
951 | int minp = 0; |
---|
952 | n=0; |
---|
953 | for(i=size(ind);i>0;i--) |
---|
954 | { |
---|
955 | if (ind[i]!=0) { |
---|
956 | n++; |
---|
957 | } else { |
---|
958 | if(var(i)==coords[1] || var(i)==coords[2] || var(i)==coords[3]) { |
---|
959 | ind[i]=1; |
---|
960 | n++; |
---|
961 | } |
---|
962 | } |
---|
963 | } |
---|
964 | |
---|
965 | params = params + npars(basering); |
---|
966 | n = n + npars(basering); |
---|
967 | if((npars(basering) == 1) && (minpoly != 0)) { |
---|
968 | minp = 1; |
---|
969 | } else { |
---|
970 | minp = 0; |
---|
971 | } |
---|
972 | string str_I = ""; |
---|
973 | for(i=1; i<=npars(basering); i=i+1) { |
---|
974 | if(!(parstr(i) == "i")) { |
---|
975 | if(minp==1) { |
---|
976 | str_I = str_I + sprintf("number %s = %s; ", parstr(i), rootminpoly()); |
---|
977 | } else { |
---|
978 | } |
---|
979 | } |
---|
980 | } |
---|
981 | int bshort = short; short = 0; |
---|
982 | if(!(minp==1 || npars(basering)==0)) { |
---|
983 | p=cleardenom(p); |
---|
984 | err_mes="Cannot plot equations with a parameter without a specified minpoly"; |
---|
985 | ERROR(err_mes); |
---|
986 | } |
---|
987 | str_I = str_I + "poly p = " + string(p) + ";"; |
---|
988 | |
---|
989 | short = bshort; |
---|
990 | |
---|
991 | if(params==0) { |
---|
992 | if (n<=2 or n>=4) |
---|
993 | { |
---|
994 | err_mes="Cannot plot equations with "+string(n)+" variables"; |
---|
995 | ERROR(err_mes); |
---|
996 | // return("0"); |
---|
997 | } |
---|
998 | if(n==4) { |
---|
999 | ring r=(real,30,30),(xx,yy,zz,ww),dp; |
---|
1000 | } else { |
---|
1001 | ring r=(real,30,30),(x,y,z),dp; |
---|
1002 | } |
---|
1003 | } else { |
---|
1004 | if(n-params<=2 || n-params>=4) { |
---|
1005 | err_mes="Cannot plot equations with "+string(n-params)+" variables"; |
---|
1006 | ERROR(err_mes); |
---|
1007 | // return("0"); |
---|
1008 | } else { |
---|
1009 | if(params == 1) { |
---|
1010 | if(n-params==3) { |
---|
1011 | if(minp==1) { |
---|
1012 | // switch to a ring without minimal polynomial: |
---|
1013 | execute("ring rr = (real,30,30),("+varstr(base)+"), dp;"); |
---|
1014 | // rr; |
---|
1015 | // "str_I",str_I; |
---|
1016 | execute(str_I); |
---|
1017 | def base = rr; |
---|
1018 | ring r=(real,30,30),(x,y,z),dp; |
---|
1019 | } else { |
---|
1020 | p=cleardenom(p); |
---|
1021 | ring r=(real,30,30),(x,y,z,p1),dp; |
---|
1022 | } |
---|
1023 | } |
---|
1024 | } |
---|
1025 | if(params == 2) { |
---|
1026 | if(n-params==3) { |
---|
1027 | p=cleardenom(p); |
---|
1028 | ring r=(real,30,30),(x,y,z,p1,p2),dp; |
---|
1029 | } |
---|
1030 | } |
---|
1031 | if(params == 3) { |
---|
1032 | if(n-params==3) { |
---|
1033 | p=cleardenom(p); |
---|
1034 | execute("ring rr = (real,30,30),("+varstr(base)+","+parstr(base)+"), dp;"); |
---|
1035 | rr; |
---|
1036 | "str_I",str_I; |
---|
1037 | execute(str_I); |
---|
1038 | "pnew:",p; |
---|
1039 | def base = rr; |
---|
1040 | |
---|
1041 | ring r=(real,30,30),(x,y,z,p1,p2,p3),dp; |
---|
1042 | } |
---|
1043 | } |
---|
1044 | } |
---|
1045 | } |
---|
1046 | // basering; |
---|
1047 | short=0; |
---|
1048 | map phi=base,0; |
---|
1049 | j=1; |
---|
1050 | |
---|
1051 | for(i=1;i<=mynvars;i++) |
---|
1052 | { |
---|
1053 | if (ind[i]!=0) |
---|
1054 | { |
---|
1055 | phi[i]=var(j); |
---|
1056 | j++; |
---|
1057 | } |
---|
1058 | } |
---|
1059 | poly p=(simplify(phi(p),1)); |
---|
1060 | if (leadcoef(p) <0) { |
---|
1061 | if(size(#)>1) { |
---|
1062 | if(#[2]!=0) { |
---|
1063 | p=-p; |
---|
1064 | } |
---|
1065 | } else { |
---|
1066 | p=-p; |
---|
1067 | } |
---|
1068 | } |
---|
1069 | if(leadcoef(p)!=0) { |
---|
1070 | p = p/leadcoef(p); |
---|
1071 | } |
---|
1072 | string thesurfstr = string(p); |
---|
1073 | if(minp == 1) { |
---|
1074 | // replace k by rootRepl |
---|
1075 | } |
---|
1076 | |
---|
1077 | return (thesurfstr); |
---|
1078 | } // end of surfEqn() |
---|
1079 | example |
---|
1080 | { "EXAMPLE:"; echo =2; |
---|
1081 | |
---|
1082 | ring rr0 = 0,(x(1..3)),dp; |
---|
1083 | poly p = x(1)^3 - x(2)^2; |
---|
1084 | print(surfEqn(p,list(x(1),x(2),x(3)))); |
---|
1085 | |
---|
1086 | ring rr1 = 0,(x,y,z),dp; |
---|
1087 | poly I(1) = 2x2-1/2x3 +1-y+1; |
---|
1088 | print(surfEqn(I(1),list(x,y,z))); |
---|
1089 | |
---|
1090 | // Steiner surface |
---|
1091 | poly J(2) = x^2*y^2+x^2*z^2+y^2*z^2-17*x*y*z; |
---|
1092 | print(surfEqn(J(2),list(x,y,z))); |
---|
1093 | } // end of example surfEqn() |
---|
1094 | |
---|
1095 | |
---|
1096 | proc num_of_vars(ideal I) |
---|
1097 | " |
---|
1098 | USAGE: num_of_vars(ideal I) |
---|
1099 | |
---|
1100 | RETURN: an intvec containing one entry for each ring variable. |
---|
1101 | each contains the sums of all degrees in this variable of all monomials |
---|
1102 | occuring in the ideal. |
---|
1103 | An entry is zero iff the corresponding variable does not occur in the ideal. |
---|
1104 | " |
---|
1105 | { |
---|
1106 | intvec v; |
---|
1107 | int i; |
---|
1108 | poly p; |
---|
1109 | for(i=size(I);i>0;i--) |
---|
1110 | { |
---|
1111 | p=I[i]; |
---|
1112 | while(p!=0) |
---|
1113 | { |
---|
1114 | v=v+leadexp(p); |
---|
1115 | p=p-lead(p); |
---|
1116 | } |
---|
1117 | } |
---|
1118 | return(v); |
---|
1119 | } |
---|
1120 | example { |
---|
1121 | "EXAMPLE:"; echo = 2; |
---|
1122 | ring r = 0, (x,y,z),dp; |
---|
1123 | ideal j0 = x^2-x*y; |
---|
1124 | num_of_vars(j0); |
---|
1125 | ideal j1 = x^2-x*y-y; |
---|
1126 | num_of_vars(j1); |
---|
1127 | ideal j2 = x^2-x*y-y, x^3-2*y; |
---|
1128 | num_of_vars(j2); |
---|
1129 | } |
---|
1130 | |
---|
1131 | |
---|
1132 | proc num_vars_id(ideal I) |
---|
1133 | " |
---|
1134 | USAGE: num_vars_id(ideal I) |
---|
1135 | |
---|
1136 | RETURN: The number of ring-variables occurring in the ideal I. |
---|
1137 | " |
---|
1138 | { |
---|
1139 | intvec v = num_of_vars(I); |
---|
1140 | int num = 0; |
---|
1141 | for(int i=size(v);i>0;i--) |
---|
1142 | { |
---|
1143 | if (v[i]!=0) { num++; } |
---|
1144 | } |
---|
1145 | return(num); |
---|
1146 | } |
---|
1147 | example { |
---|
1148 | "EXAMPLE:"; echo = 2; |
---|
1149 | ring r = 0, (x,y,z),dp; |
---|
1150 | ideal j = x^2-y, x^3-2; |
---|
1151 | num_vars_id(j); |
---|
1152 | } |
---|
1153 | |
---|
1154 | proc findInList(list obj, list l) |
---|
1155 | " |
---|
1156 | USAGE: findInList(list obj, list l) |
---|
1157 | Tries to find the object obj in the list l. |
---|
1158 | |
---|
1159 | ASSUME: the object obj[1] can be compared to the objects in the list l |
---|
1160 | |
---|
1161 | RETURN: if obj[1]=l[i] for some i, then return the first such i, |
---|
1162 | otherwise return 0 |
---|
1163 | " |
---|
1164 | { |
---|
1165 | for(int i=1; i<=size(l); i++) { |
---|
1166 | if(l[i]==obj[1]) { |
---|
1167 | return(i); |
---|
1168 | } |
---|
1169 | } |
---|
1170 | |
---|
1171 | return(0); |
---|
1172 | } |
---|
1173 | example { |
---|
1174 | "EXAMPLE:"; echo = 2; |
---|
1175 | ring r = 0,(x,y,z), dp; |
---|
1176 | list a = list(x^2+y^2+z^2+1, x^2+y^2+z^2-1, x^2+y^2-z^2+1, x^2+y^2-z^2-1); |
---|
1177 | findInList(x^2+y^2+z^2-1, a); |
---|
1178 | findInList(x^2+y^2+z^2, a); |
---|
1179 | } |
---|
1180 | |
---|
1181 | proc std_primdecGTZ(ideal I, list #) |
---|
1182 | " |
---|
1183 | USAGE: std_primdecGTZ(ideal I, list #) |
---|
1184 | Computes a primdary decomposition pd of I using primdecGTZ and then |
---|
1185 | calls std_for_pd(pd). |
---|
1186 | For the output and options, consult the help of std_for_pd. |
---|
1187 | |
---|
1188 | RETURN: see std_for_pd. |
---|
1189 | " |
---|
1190 | { |
---|
1191 | list pd = primdecGTZ(I); |
---|
1192 | return(std_for_pd(pd, #)); |
---|
1193 | } |
---|
1194 | example { |
---|
1195 | "EXAMPLE:"; echo = 2; |
---|
1196 | |
---|
1197 | ring r = 0, (x,y), dp; |
---|
1198 | ideal j = y-x^2,z-x^3; |
---|
1199 | primdecGTZ(j); |
---|
1200 | std_primdecGTZ(j); |
---|
1201 | std_primdecGTZ(j,1); |
---|
1202 | } |
---|
1203 | |
---|
1204 | proc std_for_pd(list pd, list #) |
---|
1205 | " |
---|
1206 | USAGE: std_for_pd(list pd, list #) |
---|
1207 | Call std for each of the prime ideals in the list pd |
---|
1208 | replace the prime ideals by their standard-basis. |
---|
1209 | Compute dim() and mult() of each prime component using these standard bases. |
---|
1210 | If an additional argument is given then do the same for the primary components. |
---|
1211 | |
---|
1212 | ASSUME: |
---|
1213 | pd is in the format produced by primdecGTZ() or primdecSY(). |
---|
1214 | |
---|
1215 | RETURN: A list, say l, of lists, similar to a list returned by primdecSY() or primdecGTZ(). |
---|
1216 | However, each of the entries of l (which is a list l[i]) contains some additional entries: |
---|
1217 | l[1]: the primary ideal |
---|
1218 | l[2]: a standard basis of the associated prime ideal |
---|
1219 | l[3]: dim() of this prime ideal |
---|
1220 | l[4]: mult() of this prime ideal |
---|
1221 | |
---|
1222 | If an additional argument # is given then l[1] changes: |
---|
1223 | l[1]: a standard basis of the primary ideal |
---|
1224 | Morever, there are some more entries: |
---|
1225 | l[5]: dim() of this primary ideal |
---|
1226 | l[6]: mult() of this primary ideal |
---|
1227 | l[7]: l[6] / l[5] |
---|
1228 | " |
---|
1229 | { |
---|
1230 | |
---|
1231 | if(typeof(pd[1])=="ideal") { |
---|
1232 | // this is a Singular bug!? |
---|
1233 | // "bug!";pd;"---"; |
---|
1234 | pd = list(list(pd[1], pd[1])); |
---|
1235 | // pd;$; |
---|
1236 | } |
---|
1237 | list pd_neu; |
---|
1238 | int i; |
---|
1239 | list coords; |
---|
1240 | ideal stdtmp; |
---|
1241 | ideal stdtmp2; |
---|
1242 | for(i=1; i<=size(pd); i++) { |
---|
1243 | stdtmp = std(pd[i][2]); |
---|
1244 | stdtmp2 = pd[i][1]; |
---|
1245 | if(size(#)>0) { |
---|
1246 | stdtmp2 = std(stdtmp2); |
---|
1247 | if(mult(stdtmp)==0) { |
---|
1248 | pd_neu[i] = list(stdtmp2, |
---|
1249 | stdtmp, |
---|
1250 | dim(stdtmp), mult(stdtmp), |
---|
1251 | dim(stdtmp2), mult(stdtmp2), |
---|
1252 | 0); |
---|
1253 | } else { |
---|
1254 | pd_neu[i] = list(stdtmp2, |
---|
1255 | stdtmp, |
---|
1256 | dim(stdtmp), mult(stdtmp), |
---|
1257 | dim(stdtmp2), mult(stdtmp2), |
---|
1258 | mult(stdtmp2)/mult(stdtmp)); |
---|
1259 | } |
---|
1260 | } else { |
---|
1261 | pd_neu[i] = list(stdtmp2, |
---|
1262 | stdtmp, |
---|
1263 | dim(stdtmp), mult(stdtmp)); |
---|
1264 | } |
---|
1265 | } |
---|
1266 | return(pd_neu); |
---|
1267 | } |
---|
1268 | example { |
---|
1269 | "EXAMPLE:"; echo = 2; |
---|
1270 | |
---|
1271 | ring r = 0, (x,y,z), dp; |
---|
1272 | ideal j = y-x^2,z-x^3; |
---|
1273 | list pd = primdecGTZ(j); |
---|
1274 | pd; |
---|
1275 | std_for_pd(pd, 1); |
---|
1276 | } |
---|
1277 | |
---|
1278 | proc real_solve(ideal to_solve) |
---|
1279 | " |
---|
1280 | USAGE: real_solve(ideal to_solve) |
---|
1281 | |
---|
1282 | RETURN: a list of all real solutions (as strings) |
---|
1283 | of the zero-dimensional ideal to_solve (without multiplicities). |
---|
1284 | |
---|
1285 | REMARK: Until now, it may happen that some points appear more than once. |
---|
1286 | " |
---|
1287 | { |
---|
1288 | int k; |
---|
1289 | int i; |
---|
1290 | |
---|
1291 | // def Isolring = solve(to_solve,30,0,60,"nodisplay"); |
---|
1292 | def Isolring = solve(to_solve,9,0,13,"nodisplay"); |
---|
1293 | setring Isolring; |
---|
1294 | // list SOL = solve(to_solve, "oldring", "nodisplay"); |
---|
1295 | list real_sols = list(); |
---|
1296 | list tmpl; |
---|
1297 | for(k=1; k<=size(SOL); k++) { |
---|
1298 | if(find(string(SOL[k]),"I")==0 && find(string(SOL[k]),"i")==0) { |
---|
1299 | tmpl = list(); |
---|
1300 | for(i=1; i<=size(SOL[k]); i++) { |
---|
1301 | tmpl = tmpl + list(string(SOL[k][i])); |
---|
1302 | } |
---|
1303 | real_sols = real_sols + list(tmpl); |
---|
1304 | } |
---|
1305 | } |
---|
1306 | return(real_sols); |
---|
1307 | } |
---|
1308 | example { |
---|
1309 | "EXAMPLE:"; echo = 2; |
---|
1310 | ring r = 0, (x,y), dp; |
---|
1311 | number a = 2; |
---|
1312 | number b = 3; |
---|
1313 | ideal j = (x^2-a),(y^3-b); |
---|
1314 | real_solve(j); |
---|
1315 | } |
---|
1316 | |
---|
1317 | proc rootminpoly(list #) |
---|
1318 | " |
---|
1319 | USAGE: rootminpoly(list #) |
---|
1320 | |
---|
1321 | RETURN: A root of the current minpoly |
---|
1322 | as a string representation of a complex number with |
---|
1323 | the given precision #[1] (default: 30). |
---|
1324 | E.g. ring r=(0,s),x,dp; minpoly = s^2-2; => rootminpoly() 1.41421356237309504880168872421 |
---|
1325 | |
---|
1326 | ASSUME: The current minpoly is non-zero. |
---|
1327 | " |
---|
1328 | { |
---|
1329 | int prec = 30; |
---|
1330 | int k, done; |
---|
1331 | if(size(#)>0) { |
---|
1332 | prec = #[1]; |
---|
1333 | } |
---|
1334 | short = 0; |
---|
1335 | string str_lag = sprintf("list lag = laguerre_solve(%s);", minpoly); |
---|
1336 | string str_ring = sprintf("ring r_sqrt = (complex,prec,I),(%s),lp;", parstr(basering)); |
---|
1337 | execute(str_ring); |
---|
1338 | execute(str_lag); |
---|
1339 | // lag; |
---|
1340 | // choose a real solution, if it exists: |
---|
1341 | done = 0; |
---|
1342 | for(k=1; k<=size(lag) && done==0; k++) { |
---|
1343 | if(find(string(lag[k]),"I")==0) { |
---|
1344 | done = k; |
---|
1345 | } |
---|
1346 | } |
---|
1347 | if(done==0) { |
---|
1348 | // "no real solution."; |
---|
1349 | } |
---|
1350 | |
---|
1351 | if(size(lag)>2) { |
---|
1352 | // return the first real solution |
---|
1353 | return(sprintf("%s",lag[done])); |
---|
1354 | } |
---|
1355 | |
---|
1356 | if(sprintf("%s",lag[1])[1] == "-") { |
---|
1357 | return(sprintf("%s",lag[2])); |
---|
1358 | } else { |
---|
1359 | if(sprintf("%s",lag[1])[1] == "(") { |
---|
1360 | if(sprintf("%s",lag[1])[2] == "-") { |
---|
1361 | return(sprintf("%s",lag[2])); |
---|
1362 | } else { |
---|
1363 | return(sprintf("%s",lag[1])); |
---|
1364 | } |
---|
1365 | } else { |
---|
1366 | return(sprintf("%s",lag[1])); |
---|
1367 | } |
---|
1368 | } |
---|
1369 | short = 1; |
---|
1370 | } |
---|
1371 | example |
---|
1372 | { |
---|
1373 | "EXAMPLE:"; echo =2; |
---|
1374 | ring r=(0,s),x,dp; |
---|
1375 | minpoly = s^2-2; |
---|
1376 | rootminpoly(); |
---|
1377 | |
---|
1378 | ring R=(0,s),x,dp; |
---|
1379 | minpoly = s^2+2; |
---|
1380 | rootminpoly(); |
---|
1381 | } |
---|
1382 | |
---|
1383 | proc allroots_minpoly(list #) |
---|
1384 | " |
---|
1385 | USAGE: allroots_minpoly(list #) |
---|
1386 | |
---|
1387 | RETURN: a list of strings containing all real roots of the minimal polynomial of the active ring. |
---|
1388 | |
---|
1389 | ASSUME: The current minpoly is non-zero. |
---|
1390 | " |
---|
1391 | { |
---|
1392 | int prec = 30; |
---|
1393 | int k, done; |
---|
1394 | if(size(#)>0) { |
---|
1395 | prec = #[1]; |
---|
1396 | } |
---|
1397 | short = 0; |
---|
1398 | string str_lag = sprintf("list lag = laguerre_solve(%s);", minpoly); |
---|
1399 | string str_ring = sprintf("ring r_sqrt = (complex,prec,I),(%s),lp;", parstr(basering)); |
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1400 | execute(str_ring); |
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1401 | execute(str_lag); |
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1402 | |
---|
1403 | // only take the real solutions: |
---|
1404 | done = 0; |
---|
1405 | list real_sols = list(); |
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1406 | for(k=1; k<=size(lag) && done==0; k++) { |
---|
1407 | if(find(string(lag[k]),"I")==0) { |
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1408 | real_sols = real_sols + list(string(lag[k])); |
---|
1409 | } |
---|
1410 | } |
---|
1411 | return(real_sols); |
---|
1412 | } |
---|
1413 | example { |
---|
1414 | "EXAMPLE:"; echo = 2; |
---|
1415 | ring r=(0,s),x,dp; |
---|
1416 | minpoly = s^3-2; |
---|
1417 | allroots_minpoly(); |
---|
1418 | |
---|
1419 | ring R=(0,s),x,dp; |
---|
1420 | minpoly = s^2-2; |
---|
1421 | allroots_minpoly(); |
---|
1422 | } |
---|
1423 | |
---|
1424 | proc decstr2ratstr(string str) |
---|
1425 | " |
---|
1426 | USAGE: decstr2ratstr(string str) |
---|
1427 | Convert a decimal number of not more than 30 digits to a rational number with 14 digits. |
---|
1428 | |
---|
1429 | REMARK: This procedure still has to be adapted to accept other precisions! |
---|
1430 | " |
---|
1431 | { |
---|
1432 | ring decR = (complex,30,I),(x),lp; |
---|
1433 | execute("number r="+str+";"); |
---|
1434 | execute("r = "+truncdec(r,14)+";"); |
---|
1435 | return(real2ratstr(r)); |
---|
1436 | } |
---|
1437 | |
---|
1438 | proc real2ratstr(number r) |
---|
1439 | " |
---|
1440 | USAGE: real2ratstr(number r) |
---|
1441 | |
---|
1442 | RETURN: A string containing a rational number representing the decimal number r. |
---|
1443 | |
---|
1444 | ASSUME: The current ring has either real or complex base field. |
---|
1445 | " |
---|
1446 | { |
---|
1447 | string ratstr = "number("+string(r*number(10000000000000000))+")/number(10000000000000000)"; |
---|
1448 | return(ratstr); |
---|
1449 | } |
---|
1450 | |
---|
1451 | proc truncdec(number r, int decs) |
---|
1452 | " |
---|
1453 | USAGE: truncdec(number r, int decs) |
---|
1454 | Truncates a decimal number r to the given number (decs) of digits. |
---|
1455 | |
---|
1456 | RETURN: A string representing the truncated number. |
---|
1457 | " |
---|
1458 | { |
---|
1459 | string str = string(r); |
---|
1460 | return(str[1,(decs+2)]); |
---|
1461 | } |
---|
1462 | |
---|
1463 | proc string_of_vars(ideal I) |
---|
1464 | " |
---|
1465 | USAGE: string_of_vars(ideal I) |
---|
1466 | |
---|
1467 | RETURN: A string of all variables contained in the ideal I, separated by commas. |
---|
1468 | " |
---|
1469 | { |
---|
1470 | list listvars = list(); |
---|
1471 | intvec v; |
---|
1472 | int i; |
---|
1473 | poly p; |
---|
1474 | for(i=size(I);i>0;i--) |
---|
1475 | { |
---|
1476 | p=I[i]; |
---|
1477 | while(p!=0) |
---|
1478 | { |
---|
1479 | v=v+leadexp(p); |
---|
1480 | p=p-lead(p); |
---|
1481 | } |
---|
1482 | } |
---|
1483 | for(i=1; i<=nvars(basering); i++) { |
---|
1484 | if(v[i] > 0) { |
---|
1485 | listvars = listvars + list(var(i)); |
---|
1486 | } |
---|
1487 | } |
---|
1488 | string strvars = string(listvars); |
---|
1489 | return(strvars); |
---|
1490 | } |
---|