[449fbf] | 1 | /////////////////////////////////////////////////////////////////////////////// |
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[1a3911] | 2 | version="$Id: atkins.lib,v 1.6 2009-04-06 12:39:02 seelisch Exp $"; |
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[449fbf] | 3 | category="Teaching"; |
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| 4 | info=" |
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[abb4919] | 5 | LIBRARY: atkins.lib Procedures for teaching cryptography |
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[1a3911] | 6 | AUTHOR: Stefan Steidel, steidel@mathematik.uni-kl.de |
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[449fbf] | 7 | |
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| 8 | NOTE: The library contains auxiliary procedures to compute the elliptic |
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[0c0b9f1] | 9 | curve primality test of Atkin and the Atkin's Test itself. |
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[449fbf] | 10 | The library is intended to be used for teaching purposes but not |
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[1a3911] | 11 | for serious computations. Sufficiently high printlevel allows to |
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[449fbf] | 12 | control each step, thus illustrating the algorithms at work. |
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| 13 | |
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| 14 | |
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| 15 | PROCEDURES: |
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[3eadab] | 16 | newTest(L,D) checks if number D already exists in list L |
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| 17 | bubblesort(L) sorts elements of the list L |
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| 18 | disc(N,k) generates a list of negative discriminants |
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| 19 | Cornacchia(d,p) computes solution (x,y) for x^2+d*y^2=p |
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| 20 | CornacchiaModified(D,p) computes solution (x,y) for x^2+|D|*y^2=4p |
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| 21 | maximum(L) computes the maximal number contained in L |
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[1a3911] | 22 | sqr(w,k) computes the square root of w w.r.t. accuracy k |
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[3eadab] | 23 | expo(z,k) computes exp(z) |
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| 24 | jOft(t,k) computes the j-invariant of t |
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| 25 | round(r) rounds r to the nearest number out of Z |
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| 26 | HilbertClassPoly(D,k) computes the Hilbert Class Polynomial |
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| 27 | rootsModp(p,P) computes roots of the polynomial P modulo p |
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| 28 | wUnit(D) computes the number of units in Q(sqr(D)) |
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| 29 | Atkin(N,K,B) tries to prove that N is prime |
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[d1b0065] | 30 | |
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[449fbf] | 31 | "; |
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| 32 | |
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[abb4919] | 33 | LIB "crypto.lib"; |
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[449fbf] | 34 | LIB "general.lib"; |
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| 35 | LIB "ntsolve.lib"; |
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| 36 | LIB "inout.lib"; |
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| 37 | |
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| 38 | /////////////////////////////////////////////////////////////////////////////// |
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| 39 | |
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[3eadab] | 40 | proc newTest(list L, number D) |
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| 41 | "USAGE: newTest(L,D); |
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[53e03a6] | 42 | RETURN: 1, if D does not already exist in L, |
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| 43 | -1, if D does already exist in L |
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| 44 | EXAMPLE:example new; shows an example |
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| 45 | " |
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| 46 | { |
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[ea9f7aa] | 47 | number a=1; // a=1 bedeutet: D noch nicht in L vorhanden |
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| 48 | int i; |
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| 49 | for(i=1;i<=size(L);i++) |
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| 50 | { |
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| 51 | if(D==L[i]) |
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| 52 | { |
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| 53 | a=-1; // a=-1 bedeutet: D bereits in L vorhanden |
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| 54 | break; |
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| 55 | } |
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| 56 | } |
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| 57 | return(a); |
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[53e03a6] | 58 | } |
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[449fbf] | 59 | example |
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[53e03a6] | 60 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 61 | ring r = 0,x,dp; |
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| 62 | list L=8976,-223456,556,-778,3,-55603,45,766677; |
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| 63 | number D=-55603; |
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[3eadab] | 64 | newTest(L,D); |
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[53e03a6] | 65 | } |
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[449fbf] | 66 | |
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| 67 | proc bubblesort(list L) |
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[53e03a6] | 68 | "USAGE: bubblesort(L); |
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| 69 | RETURN: list L, sort in decreasing order |
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| 70 | EXAMPLE:example bubblesort; shows an example |
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| 71 | " |
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| 72 | { |
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[ea9f7aa] | 73 | number b; |
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| 74 | int n,i,j; |
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| 75 | while(j==0) |
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| 76 | { |
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| 77 | i=i+1; |
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| 78 | j=1; |
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| 79 | for(n=1;n<=size(L)-i;n++) |
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| 80 | { |
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| 81 | if(L[n]<L[n+1]) |
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| 82 | { |
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| 83 | b=L[n]; |
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| 84 | L[n]=L[n+1]; |
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| 85 | L[n+1]=b; |
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| 86 | j=0; |
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| 87 | } |
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| 88 | } |
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| 89 | } |
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| 90 | return(L); |
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[53e03a6] | 91 | } |
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[449fbf] | 92 | example |
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[53e03a6] | 93 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 94 | ring r = 0,x,dp; |
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| 95 | list L=-567,-233,446,12,-34,8907; |
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| 96 | bubblesort(L); |
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[53e03a6] | 97 | } |
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[449fbf] | 98 | |
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| 99 | proc disc(number N, int k) |
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[53e03a6] | 100 | "USAGE: disc(N,k); |
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[1a3911] | 101 | RETURN: list L of negative discriminants D, sorted in decreasing order |
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[53e03a6] | 102 | ASSUME: D<0, D kongruent 0 or 1 modulo 4 and |D|<4N |
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| 103 | NOTE: D=b^2-4*a, where 0<=b<=k and intPart((b^2)/4)+1<=a<=k for each b |
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| 104 | EXAMPLE:example disc; shows an example |
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| 105 | " |
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| 106 | { |
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[ea9f7aa] | 107 | list L=-3,-4,-7; |
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| 108 | number D; |
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| 109 | number B; |
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| 110 | int a,b; |
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| 111 | for(b=0;b<=k;b++) |
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| 112 | { |
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| 113 | B=b^2; |
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| 114 | for(a=int(intPart(B/4))+1;a<=k;a++) |
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| 115 | { |
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| 116 | D=-4*a+B; |
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[3eadab] | 117 | if((D<0)&&((D mod 4)!=2)&&((D mod 4)!=3)&&(absValue(D)<4*N)&&(newTest(L,D)==1)) |
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[ea9f7aa] | 118 | { |
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| 119 | L[size(L)+1]=D; |
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| 120 | } |
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| 121 | } |
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| 122 | } |
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| 123 | L=bubblesort(L); |
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| 124 | return(L); |
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[53e03a6] | 125 | } |
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[449fbf] | 126 | example |
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[53e03a6] | 127 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 128 | ring R = 0,x,dp; |
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| 129 | disc(2003,50); |
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[53e03a6] | 130 | } |
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[449fbf] | 131 | |
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| 132 | |
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| 133 | |
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| 134 | proc Cornacchia(number d, number p) |
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[53e03a6] | 135 | "USAGE: Cornacchia(d,p); |
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| 136 | RETURN: x,y such that x^2+d*y^2=p with p prime, |
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| 137 | -1, if the Diophantine equation has no solution, |
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| 138 | 0, if the parameters are wrong selected |
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| 139 | ASSUME: 0<d<p |
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| 140 | EXAMPLE:example Cornacchia; shows an example |
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| 141 | " |
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| 142 | { |
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[19ffafb] | 143 | if((d<0)||(p<d)) // (0)[Test if assumptions well-defined] |
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[ea9f7aa] | 144 | { |
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| 145 | return(0); |
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| 146 | // ERROR("Parameters wrong selected! It has to be 0<d<p!"); |
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| 147 | } |
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| 148 | else |
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| 149 | { |
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[19ffafb] | 150 | number k,x(0),a,b,l,r,c,i; |
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[ea9f7aa] | 151 | |
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[19ffafb] | 152 | k=Jacobi(-d,p); // (1)[Test if residue] |
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[ea9f7aa] | 153 | if(k==-1) |
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| 154 | { |
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| 155 | return(-1); |
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| 156 | // ERROR("The Diophantine equation has no solution!"); |
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| 157 | } |
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| 158 | else |
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| 159 | { |
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[19ffafb] | 160 | x(0)=squareRoot(-d,p); // (2)[Compute square root] |
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| 161 | if((p/2>=x(0))||(p<=x(0))) |
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| 162 | { |
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| 163 | x(0)=-x(0) mod p; |
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| 164 | } |
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| 165 | a=p; |
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| 166 | b=x(0); |
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| 167 | l=intRoot(p); |
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| 168 | while(b>l) // (3)[Euclidean algorithm] |
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| 169 | { |
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[ea9f7aa] | 170 | r=a mod b; |
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| 171 | a=b; |
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| 172 | b=r; |
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[19ffafb] | 173 | } |
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| 174 | c=(p-b^2)/d; // (4)[Test solution] |
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| 175 | i=intRoot(c); |
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| 176 | if((((p-b^2) mod d)!=0)||(c!=i^2)) |
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| 177 | { |
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| 178 | return(-1); |
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| 179 | } |
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| 180 | else |
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| 181 | { |
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[ea9f7aa] | 182 | list L=b,i; |
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| 183 | return(L); |
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[19ffafb] | 184 | } |
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[ea9f7aa] | 185 | } |
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| 186 | } |
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[2472afe] | 187 | } |
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[449fbf] | 188 | example |
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[53e03a6] | 189 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 190 | ring R = 0,x,dp; |
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| 191 | Cornacchia(55,9551); |
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[53e03a6] | 192 | } |
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[449fbf] | 193 | |
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| 194 | proc CornacchiaModified(number D, number p) |
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[53e03a6] | 195 | "USAGE: CornacchiaModified(D,p); |
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| 196 | RETURN: x,y such that x^2+|D|*y^2=p with p prime, |
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| 197 | -1, if the Diophantine equation has no solution, |
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| 198 | 0, if the parameters are wrong selected |
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| 199 | ASSUME: D<0, D kongruent 0 or 1 modulo 4 and |D|<4p |
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| 200 | EXAMPLE:example CornacchiaModified; shows an example |
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| 201 | " |
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| 202 | { |
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[26508d] | 203 | if((D>=0)||((D mod 4)==2)||((D mod 4)==3)||(absValue(D)>=4*p)) |
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| 204 | {// (0)[Test if assumptions well-defined] |
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| 205 | return(0); |
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| 206 | // ERROR("Parameters wrong selected!"); |
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| 207 | } |
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| 208 | else |
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| 209 | { |
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| 210 | if(p==2) // (1)[Case p=2] |
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| 211 | { |
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| 212 | if((D+8)==intRoot(D+8)^2) |
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[19ffafb] | 213 | { |
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[26508d] | 214 | return(intRoot(D+8),1); |
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[19ffafb] | 215 | } |
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[449fbf] | 216 | else |
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[19ffafb] | 217 | { |
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[26508d] | 218 | return(-1); |
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| 219 | // ERROR("The Diophantine equation has no solution!"); |
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| 220 | } |
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| 221 | } |
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| 222 | else |
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| 223 | { |
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| 224 | number k,x(0),a,b,l,r,c; |
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| 225 | k=Jacobi(D,p); // (2)[Test if residue] |
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| 226 | if(k==-1) |
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| 227 | { |
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| 228 | return(-1); |
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| 229 | // ERROR("The Diophantine equation has no solution!"); |
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[19ffafb] | 230 | } |
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[26508d] | 231 | else |
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| 232 | { |
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| 233 | x(0)=squareRoot(D,p); // (3)[Compute square root] |
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| 234 | if((x(0) mod 2)!=(D mod 2)) |
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| 235 | { |
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| 236 | x(0)=p-x(0); |
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| 237 | } |
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| 238 | a=2*p; |
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| 239 | b=x(0); |
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| 240 | l=intRoot(4*p); |
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| 241 | while(b>l) // (4)[Euclidean algorithm] |
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| 242 | { |
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| 243 | r=a mod b; |
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| 244 | a=b; |
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| 245 | b=r; |
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| 246 | } |
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| 247 | c=(4*p-b^2)/absValue(D);// (5)[Test solution] |
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| 248 | if((((4*p-b^2) mod absValue(D))!=0)||(c!=intRoot(c)^2)) |
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| 249 | { |
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| 250 | return(-1); |
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| 251 | // ERROR("The Diophantine equation has no solution!"); |
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| 252 | } |
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| 253 | else |
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| 254 | { |
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| 255 | list L=b,intRoot(c); |
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| 256 | return(L); |
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| 257 | } |
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| 258 | } |
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| 259 | } |
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| 260 | } |
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[53e03a6] | 261 | } |
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[449fbf] | 262 | example |
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[53e03a6] | 263 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 264 | ring R = 0,x,dp; |
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| 265 | CornacchiaModified(-107,1319); |
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[53e03a6] | 266 | } |
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[449fbf] | 267 | |
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| 268 | proc pFactor1(number n,int B, list P) |
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[53e03a6] | 269 | "USAGE: pFactor1(n,B,P); n to be factorized, B a bound , P a list of primes |
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| 270 | RETURN: a list of factors of n or the message: no factor found |
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| 271 | NOTE: Pollard's p-factorization |
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| 272 | creates the product k of powers of primes (bounded by B) from |
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| 273 | the list P with the idea that for a prime divisor p of n p-1|k |
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| 274 | then p devides gcd(a^k-1,n) for some random a |
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| 275 | EXAMPLE:example pFactor1; shows an example |
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| 276 | " |
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| 277 | { |
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[26508d] | 278 | int i; |
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| 279 | number k=1; |
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| 280 | number w; |
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| 281 | while(i<size(P)) |
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| 282 | { |
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| 283 | i++; |
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| 284 | w=P[i]; |
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| 285 | if(w>B) {break;} |
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| 286 | while(w*P[i]<=B) |
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| 287 | { |
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| 288 | w=w*P[i]; |
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| 289 | } |
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| 290 | k=k*w; |
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| 291 | } |
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| 292 | number a=random(2,2147483629); |
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| 293 | number d=gcdN(powerN(a,k,n)-1,n); |
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| 294 | if((d>1)&&(d<n)){return(d);} |
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| 295 | return(n); |
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[53e03a6] | 296 | } |
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[449fbf] | 297 | example |
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| 298 | { "EXAMPLE:"; echo = 2; |
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| 299 | ring R = 0,z,dp; |
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| 300 | list L=primList(1000); |
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| 301 | pFactor1(1241143,13,L); |
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| 302 | number h=10; |
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| 303 | h=h^30+25; |
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| 304 | pFactor1(h,20,L); |
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| 305 | } |
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| 306 | |
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| 307 | proc maximum(list L) |
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[53e03a6] | 308 | "USAGE: maximum(list L); |
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| 309 | RETURN: the maximal number contained in list L |
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| 310 | EXAMPLE:example maximum; shows an example |
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| 311 | " |
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| 312 | { |
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[26508d] | 313 | number max=L[1]; |
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| 314 | int i; |
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| 315 | for(i=2;i<=size(L);i++) |
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| 316 | { |
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| 317 | if(L[i]>max) |
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| 318 | { |
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| 319 | max=L[i]; |
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| 320 | } |
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| 321 | } |
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| 322 | return(max); |
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[53e03a6] | 323 | } |
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[449fbf] | 324 | example |
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[53e03a6] | 325 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 326 | ring r = 0,x,dp; |
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| 327 | list L=465,867,1233,4567,776544,233445,2334,556; |
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| 328 | maximum(L); |
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[53e03a6] | 329 | } |
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[449fbf] | 330 | |
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[3eadab] | 331 | static proc cmod(number x, number y) |
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[53e03a6] | 332 | "USAGE: cmod(x,y); |
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| 333 | RETURN: x mod y |
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| 334 | ASSUME: x,y out of Z and x,y<=2147483647 |
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| 335 | NOTE: this algorithm is a helping procedure to be able to calculate |
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| 336 | x mod y with x,y out of Z while working in the complex field |
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| 337 | EXAMPLE:example cmod; shows an example |
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| 338 | " |
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| 339 | { |
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[26508d] | 340 | int rest=int(x-y*int(x/y)); |
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| 341 | if(rest<0) |
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| 342 | { |
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| 343 | rest=rest+int(y); |
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| 344 | } |
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| 345 | return(rest); |
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[53e03a6] | 346 | } |
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[449fbf] | 347 | example |
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[53e03a6] | 348 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 349 | ring r = (complex,30,i),x,dp; |
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| 350 | number x=-1004456; |
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| 351 | number y=1233; |
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| 352 | cmod(x,y); |
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[53e03a6] | 353 | } |
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[449fbf] | 354 | |
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[26508d] | 355 | proc sqr(number w, int k) |
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[53e03a6] | 356 | "USAGE: sqr(w,k); |
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| 357 | RETURN: the square root of w |
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| 358 | ASSUME: w>=0 |
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| 359 | NOTE: k describes the number of decimals being calculated in the real numbers, |
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| 360 | k, intPart(k/5) are inputs for the procedure "nt_solve" |
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| 361 | EXAMPLE:example sqr; shows an example |
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| 362 | " |
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| 363 | { |
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| 364 | poly f=var(1)^2-w; |
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| 365 | def S=basering; |
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| 366 | ring R=(real,k),var(1),dp; |
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| 367 | poly f=imap(S,f); |
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| 368 | ideal I=nt_solve(f,1.1,list(k,int(intPart(k/5)))); |
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| 369 | number c=leadcoef(I[1]); |
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| 370 | setring S; |
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| 371 | number c=imap(R,c); |
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| 372 | return(c); |
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| 373 | } |
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[449fbf] | 374 | example |
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[53e03a6] | 375 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 376 | ring R = (real,60),x,dp; |
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[0c0b9f1] | 377 | number ww=288469650108669535726081; |
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| 378 | sqr(ww,60); |
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[53e03a6] | 379 | } |
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[449fbf] | 380 | |
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| 381 | |
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| 382 | |
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[3eadab] | 383 | proc expo(number z, int k) |
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| 384 | "USAGE: expo(z,k); |
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[53e03a6] | 385 | RETURN: e^z to the order k |
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| 386 | NOTE: k describes the number of summands being calculated in the exponential power series |
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[1a3911] | 387 | EXAMPLE:example expo; shows an example |
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[53e03a6] | 388 | " |
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| 389 | { |
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| 390 | number q=1; |
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| 391 | number e=1; |
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| 392 | int n; |
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| 393 | for(n=1;n<=k;n++) |
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| 394 | { |
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| 395 | q=q*z/n; |
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| 396 | e=e+q; |
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| 397 | } |
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| 398 | return(e); |
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| 399 | } |
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[449fbf] | 400 | |
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| 401 | example |
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[53e03a6] | 402 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 403 | ring r = (real,30),x,dp; |
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| 404 | number z=40.35; |
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[3eadab] | 405 | expo(z,1000); |
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[53e03a6] | 406 | } |
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[449fbf] | 407 | |
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| 408 | |
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| 409 | |
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[3eadab] | 410 | proc jOft(number t, int k) |
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| 411 | "USAGE: jOft(t,k); |
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[53e03a6] | 412 | RETURN: the j-invariant of t |
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| 413 | ASSUME: t is a complex number with positive imaginary part |
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| 414 | NOTE: k describes the number of summands being calculated in the power series, |
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[1a3911] | 415 | 10*k is input for the procedure @code{expo} |
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| 416 | EXAMPLE:example jOft; shows an example |
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[53e03a6] | 417 | " |
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| 418 | { |
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[26508d] | 419 | number q1,q2,qr1,qi1,tr,ti,m1,m2,f,j; |
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| 420 | |
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| 421 | number pi=3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989; |
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| 422 | |
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| 423 | tr=repart(t); |
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| 424 | ti=impart(t); |
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| 425 | if(tr==-1/2){qr1=-1;} |
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| 426 | if(tr==0){qr1=1;} |
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| 427 | if((tr!=-1/2)&&(tr!=0)) |
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| 428 | { |
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| 429 | tr=tr-round(tr); |
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| 430 | qr1=expo(2*i*pi*tr,10*k); |
---|
| 431 | } |
---|
| 432 | |
---|
| 433 | qi1=expo(-pi*ti,10*k); |
---|
| 434 | q1=qr1*qi1^2; |
---|
| 435 | q2=q1^2; |
---|
| 436 | |
---|
| 437 | int n=1; |
---|
| 438 | while(n<=k) |
---|
| 439 | { |
---|
| 440 | m1=m1+(-1)^n*(q1^(n*(3*n-1)/2)+q1^(n*(3*n+1)/2)); |
---|
| 441 | m2=m2+(-1)^n*(q2^(n*(3*n-1)/2)+q2^(n*(3*n+1)/2)); |
---|
| 442 | n++; |
---|
| 443 | } |
---|
| 444 | |
---|
| 445 | f=q1*((1+m2)/(1+m1))^24; |
---|
[449fbf] | 446 | |
---|
[26508d] | 447 | j=(256*f+1)^3/f; |
---|
| 448 | return(j); |
---|
| 449 | } |
---|
[449fbf] | 450 | example |
---|
[53e03a6] | 451 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 452 | ring r = (complex,30,i),x,dp; |
---|
| 453 | number t=(-7+i*sqr(7,250))/2; |
---|
[3eadab] | 454 | jOft(t,50); |
---|
[53e03a6] | 455 | } |
---|
[449fbf] | 456 | |
---|
| 457 | proc round(number r) |
---|
[53e03a6] | 458 | "USAGE: round(r); |
---|
| 459 | RETURN: the nearest number to r out of Z |
---|
| 460 | ASSUME: r should be a rational or a real number |
---|
| 461 | EXAMPLE:example round; shows an example |
---|
| 462 | " |
---|
| 463 | { |
---|
| 464 | number a=absValue(r); |
---|
| 465 | number v=r/a; |
---|
| 466 | |
---|
| 467 | number d=10; |
---|
| 468 | int e; |
---|
| 469 | while(1) |
---|
| 470 | { |
---|
| 471 | e=e+1; |
---|
| 472 | if(a-d^e<0) |
---|
[449fbf] | 473 | { |
---|
[53e03a6] | 474 | e=e-1; |
---|
| 475 | break; |
---|
[449fbf] | 476 | } |
---|
[53e03a6] | 477 | } |
---|
[449fbf] | 478 | |
---|
[53e03a6] | 479 | number b=a; |
---|
| 480 | int k; |
---|
| 481 | for(k=0;k<=e;k++) |
---|
| 482 | { |
---|
| 483 | while(1) |
---|
| 484 | { |
---|
| 485 | b=b-d^(e-k); |
---|
| 486 | if(b<0) |
---|
| 487 | { |
---|
| 488 | b=b+d^(e-k); |
---|
| 489 | break; |
---|
| 490 | } |
---|
| 491 | } |
---|
| 492 | } |
---|
| 493 | |
---|
| 494 | if(b<1/2) |
---|
| 495 | { |
---|
| 496 | return(v*(a-b)); |
---|
| 497 | } |
---|
| 498 | else |
---|
| 499 | { |
---|
| 500 | return(v*(a+1-b)); |
---|
| 501 | } |
---|
| 502 | } |
---|
[449fbf] | 503 | example |
---|
[53e03a6] | 504 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 505 | ring R = (real,50),x,dp; |
---|
| 506 | number r=7357683445788723456321.6788643224; |
---|
| 507 | round(r); |
---|
[53e03a6] | 508 | } |
---|
[449fbf] | 509 | |
---|
| 510 | |
---|
| 511 | |
---|
[3eadab] | 512 | proc HilbertClassPoly(number D, int k) |
---|
| 513 | "USAGE: HilbertClassPoly(D,k); |
---|
| 514 | RETURN: the monic polynomial of degree h(D) in Z[X] of which jOft((D+sqr(D))/2) is a root |
---|
[53e03a6] | 515 | ASSUME: D is a negative discriminant |
---|
[1a3911] | 516 | NOTE: k is input for the procedure "jOft", |
---|
[53e03a6] | 517 | 5*k is input for the procedure "sqr", |
---|
| 518 | 10*k describes the number of decimals being calculated in the complex numbers |
---|
[1a3911] | 519 | EXAMPLE:example HilbertClassPoly; shows an example |
---|
[53e03a6] | 520 | " |
---|
| 521 | { |
---|
[26508d] | 522 | if(D>=0) // (0)[Test if assumptions well-defined] |
---|
| 523 | { |
---|
| 524 | ERROR("Parameter wrong selected!"); |
---|
| 525 | } |
---|
| 526 | else |
---|
| 527 | { |
---|
| 528 | def S=basering; |
---|
| 529 | ring R=0,x,dp; |
---|
[449fbf] | 530 | |
---|
[26508d] | 531 | string s1,s2,s3; |
---|
| 532 | number a1,b1,t1,g1; |
---|
| 533 | number D=imap(S,D); |
---|
| 534 | number B=intRoot(absValue(D)/3); |
---|
| 535 | |
---|
| 536 | ring C=(complex,10*k,i),x,dp; |
---|
| 537 | number D=imap(S,D); |
---|
| 538 | |
---|
| 539 | poly P=1; // (1)[Initialize] |
---|
| 540 | number b=cmod(D,2); |
---|
| 541 | number B=imap(R,B); |
---|
| 542 | |
---|
| 543 | number t,a,g,tau,j; |
---|
| 544 | list L; |
---|
| 545 | |
---|
| 546 | int step=2; |
---|
| 547 | while(1) |
---|
| 548 | { |
---|
| 549 | if(step==2) // (2)[Initialize a] |
---|
| 550 | { |
---|
| 551 | t=(b^2-D)/4; |
---|
| 552 | L=b,1; |
---|
| 553 | a=maximum(L); |
---|
| 554 | step=3; |
---|
| 555 | } |
---|
| 556 | |
---|
| 557 | if(step==3) // (3)[Test] |
---|
| 558 | { |
---|
| 559 | if((cmod(t,a)!=0)) |
---|
| 560 | { |
---|
| 561 | step=4; |
---|
| 562 | } |
---|
| 563 | else |
---|
| 564 | { |
---|
| 565 | s1=string(a); |
---|
| 566 | s2=string(b); |
---|
| 567 | s3=string(t); |
---|
| 568 | |
---|
| 569 | setring R; |
---|
| 570 | execute("a1="+s1+";"); |
---|
| 571 | execute("b1="+s2+";"); |
---|
| 572 | execute("t1="+s3+";"); |
---|
| 573 | g1=gcd(gcd(a1,b1),t1/a1); |
---|
| 574 | setring C; |
---|
| 575 | g=imap(R,g1); |
---|
| 576 | |
---|
| 577 | if(g!=1) |
---|
| 578 | { |
---|
| 579 | step=4; |
---|
| 580 | } |
---|
| 581 | else |
---|
| 582 | { |
---|
| 583 | tau=(-b+i*sqr(absValue(D),5*k))/(2*a); |
---|
| 584 | j=jOft(tau,k); |
---|
| 585 | if((a==b)||(a^2==t)||(b==0)) |
---|
| 586 | { |
---|
| 587 | P=P*(var(1)-repart(j)); |
---|
| 588 | step=4; |
---|
| 589 | } |
---|
| 590 | else |
---|
| 591 | { |
---|
| 592 | P=P*(var(1)^2-2*repart(j)*var(1)+repart(j)^2+impart(j)^2); |
---|
| 593 | step=4; |
---|
| 594 | } |
---|
| 595 | } |
---|
| 596 | } |
---|
| 597 | } |
---|
| 598 | |
---|
| 599 | if(step==4) // (4)[Loop on a] |
---|
| 600 | { |
---|
| 601 | a=a+1; |
---|
| 602 | if(a^2<=t) |
---|
| 603 | { |
---|
| 604 | step=3; |
---|
| 605 | continue; |
---|
| 606 | } |
---|
| 607 | else |
---|
| 608 | { |
---|
| 609 | step=5; |
---|
| 610 | } |
---|
| 611 | } |
---|
| 612 | |
---|
| 613 | if(step==5) // (5)[Loop on b] |
---|
| 614 | { |
---|
| 615 | b=b+2; |
---|
| 616 | if(b<=B) |
---|
| 617 | { |
---|
| 618 | step=2; |
---|
| 619 | } |
---|
| 620 | else |
---|
| 621 | { |
---|
| 622 | break; |
---|
| 623 | } |
---|
| 624 | } |
---|
| 625 | } |
---|
| 626 | |
---|
| 627 | matrix M=coeffs(P,var(1)); |
---|
| 628 | |
---|
| 629 | list liste; |
---|
| 630 | int n; |
---|
| 631 | for(n=1;n<=nrows(M);n++) |
---|
| 632 | { |
---|
| 633 | liste[n]=round(repart(number(M[n,1]))); |
---|
| 634 | } |
---|
| 635 | |
---|
| 636 | poly Q; |
---|
| 637 | int m; |
---|
| 638 | for(m=1;m<=size(liste);m++) |
---|
| 639 | { |
---|
| 640 | Q=Q+liste[m]*var(1)^(m-1); |
---|
| 641 | } |
---|
| 642 | |
---|
| 643 | string s=string(Q); |
---|
| 644 | setring S; |
---|
| 645 | execute("poly Q="+s+";"); |
---|
| 646 | return(Q); |
---|
| 647 | } |
---|
[53e03a6] | 648 | } |
---|
[449fbf] | 649 | example |
---|
[53e03a6] | 650 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 651 | ring r = 0,x,dp; |
---|
| 652 | number D=-23; |
---|
[3eadab] | 653 | HilbertClassPoly(D,50); |
---|
[53e03a6] | 654 | } |
---|
[449fbf] | 655 | |
---|
[3eadab] | 656 | proc rootsModp(int p, poly P) |
---|
| 657 | "USAGE: rootsModp(p,P); |
---|
[53e03a6] | 658 | RETURN: list of roots of the polynomial P modulo p with p prime |
---|
| 659 | ASSUME: p>=3 |
---|
| 660 | NOTE: this algorithm will be called recursively, and it is understood |
---|
| 661 | that all the operations are done in Z/pZ (excepting sqareRoot(d,p)) |
---|
[3eadab] | 662 | EXAMPLE:example rootsModp; shows an example |
---|
[53e03a6] | 663 | " |
---|
| 664 | { |
---|
[26508d] | 665 | if(p<3) // (0)[Test if assumptions well-defined] |
---|
| 666 | { |
---|
| 667 | ERROR("Parameter wrong selected, since p<3!"); |
---|
| 668 | } |
---|
| 669 | else |
---|
| 670 | { |
---|
| 671 | def S=basering; |
---|
| 672 | ring R=p,var(1),dp; |
---|
[449fbf] | 673 | |
---|
[26508d] | 674 | poly P=imap(S,P); |
---|
| 675 | number d; |
---|
| 676 | int a; |
---|
| 677 | list L; |
---|
| 678 | |
---|
| 679 | poly A=gcd(var(1)^p-var(1),P); // (1)[Isolate roots in Z/pZ] |
---|
| 680 | if(subst(A,var(1),0)==0) |
---|
| 681 | { |
---|
| 682 | L[1]=0; |
---|
| 683 | A=A/var(1); |
---|
| 684 | } |
---|
| 685 | |
---|
| 686 | if(deg(A)==0) // (2)[Small degree?] |
---|
| 687 | { |
---|
| 688 | return(L); |
---|
| 689 | } |
---|
| 690 | |
---|
| 691 | if(deg(A)==1) |
---|
| 692 | { |
---|
| 693 | matrix M=coeffs(A,var(1)); |
---|
| 694 | L[size(L)+1]=-leadcoef(M[1,1])/leadcoef(M[2,1]); |
---|
| 695 | setring S; |
---|
| 696 | list L=imap(R,L); |
---|
| 697 | return(L); |
---|
| 698 | } |
---|
| 699 | |
---|
| 700 | if(deg(A)==2) |
---|
| 701 | { |
---|
| 702 | matrix M=coeffs(A,var(1)); |
---|
| 703 | d=leadcoef(M[2,1])^2-4*leadcoef(M[1,1])*leadcoef(M[3,1]); |
---|
| 704 | |
---|
| 705 | ring T=0,var(1),dp; |
---|
| 706 | number d=imap(R,d); |
---|
| 707 | number e=squareRoot(d,p); |
---|
| 708 | setring R; |
---|
| 709 | number e=imap(T,e); |
---|
| 710 | |
---|
| 711 | L[size(L)+1]=(-leadcoef(M[2,1])+e)/(2*leadcoef(M[3,1])); |
---|
| 712 | L[size(L)+1]=(-leadcoef(M[2,1])-e)/(2*leadcoef(M[3,1])); |
---|
| 713 | setring S; |
---|
| 714 | list L=imap(R,L); |
---|
| 715 | return(L); |
---|
| 716 | } |
---|
| 717 | |
---|
| 718 | poly B=1; // (3)[Random splitting] |
---|
| 719 | poly C; |
---|
| 720 | while((deg(B)==0)||(deg(B)==deg(A))) |
---|
| 721 | { |
---|
| 722 | a=random(0,p-1); |
---|
| 723 | B=gcd((var(1)+a)^((p-1)/2)-1,A); |
---|
| 724 | C=A/B; |
---|
| 725 | } |
---|
| 726 | |
---|
| 727 | setring S; // (4)[Recurse] |
---|
| 728 | poly B=imap(R,B); |
---|
| 729 | poly C=imap(R,C); |
---|
| 730 | list l=L+rootsModp(p,B)+rootsModp(p,C); |
---|
| 731 | return(l); |
---|
| 732 | } |
---|
[53e03a6] | 733 | } |
---|
[449fbf] | 734 | example |
---|
[53e03a6] | 735 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 736 | ring r = 0,x,dp; |
---|
| 737 | poly f=x4+2x3-5x2+x; |
---|
[3eadab] | 738 | rootsModp(7,f); |
---|
[449fbf] | 739 | poly g=x5+112x4+655x3+551x2+1129x+831; |
---|
[3eadab] | 740 | rootsModp(1223,g); |
---|
[53e03a6] | 741 | } |
---|
[449fbf] | 742 | |
---|
[3eadab] | 743 | proc wUnit(number D) |
---|
| 744 | "USAGE: wUnit(D); |
---|
[53e03a6] | 745 | RETURN: the number of roots of unity in the quadratic order of discriminant D |
---|
| 746 | ASSUME: D<0 a discriminant kongruent to 0 or 1 modulo 4 |
---|
| 747 | EXAMPLE:example w; shows an example |
---|
| 748 | " |
---|
| 749 | { |
---|
| 750 | if((D>=0)||((D mod 4)==2)||((D mod 4)==3)) |
---|
| 751 | { |
---|
| 752 | ERROR("Parameter wrong selected!"); |
---|
| 753 | } |
---|
| 754 | else |
---|
| 755 | { |
---|
| 756 | if(D<-4) {return(2);} |
---|
| 757 | if(D==-4){return(4);} |
---|
| 758 | if(D==-3){return(6);} |
---|
| 759 | } |
---|
| 760 | } |
---|
[449fbf] | 761 | example |
---|
[53e03a6] | 762 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 763 | ring r = 0,x,dp; |
---|
| 764 | number D=-3; |
---|
[3eadab] | 765 | wUnit(D); |
---|
[53e03a6] | 766 | } |
---|
[449fbf] | 767 | |
---|
| 768 | |
---|
| 769 | |
---|
| 770 | proc Atkin(number N, int K, int B) |
---|
[53e03a6] | 771 | "USAGE: Atkin(N,K,B); |
---|
| 772 | RETURN: 1, if N is prime, |
---|
| 773 | -1, if N is not prime, |
---|
| 774 | 0, if the algorithm is not applicable, since there are too little discriminants |
---|
| 775 | ASSUME: N is coprime to 6 and different from 1 |
---|
[1a3911] | 776 | NOTE: K/2 is input for the procedure "disc",@* |
---|
| 777 | K is input for the procedure "HilbertClassPolynomial",@* |
---|
| 778 | B describes the number of recursions being calculated.@* |
---|
| 779 | The basis of the algorithm is the following theorem: |
---|
[d1b0065] | 780 | Let N be an integer coprime to 6 and different from 1 and E be an |
---|
[2472afe] | 781 | ellipic curve modulo N. Assume that we know an integer m and a |
---|
[1a3911] | 782 | point P of E(Z/NZ) satisfying the following conditions.@* |
---|
| 783 | (1) There exists a prime divisor q of m such that q>(4-th root(N)+1)^2.@* |
---|
| 784 | (2) m*P=O(E)=(0:1:0).@* |
---|
| 785 | (3) (m/q)*P=(x:y:t) with t element of (Z/NZ)*.@* |
---|
[53e03a6] | 786 | Then N is prime. |
---|
| 787 | EXAMPLE:example Atkin; shows an example |
---|
| 788 | " |
---|
| 789 | { |
---|
[d1b0065] | 790 | if(N==1) {return(-1);} // (0)[Test if assumptions well-defined] |
---|
| 791 | if((N==2)||(N==3)) {return(1);} |
---|
| 792 | if(gcdN(N,6)!=1) |
---|
| 793 | { |
---|
| 794 | if(printlevel>=1) {"ggT(N,6)="+string(gcdN(N,6));pause();} |
---|
| 795 | return(-1); |
---|
| 796 | } |
---|
| 797 | else |
---|
| 798 | { |
---|
| 799 | int i; // (1)[Initialize] |
---|
| 800 | int n(i); |
---|
| 801 | number N(i)=N; |
---|
| 802 | if(printlevel>=1) {"Setze i=0, n=0 und N(i)=N(0)="+string(N(i))+".";pause();} |
---|
| 803 | |
---|
| 804 | // declarations: |
---|
| 805 | int j(0),j(1),j(2),j(3),j(4),k; // running indices |
---|
| 806 | list L; // all primes smaller than 1000 |
---|
| 807 | list H; // sequence of negative discriminants |
---|
| 808 | number D; // discriminant out of H |
---|
| 809 | list L1,L2,S,S1,S2,R; // lists of relevant elements |
---|
| 810 | list P,P1,P2; // elliptic points on E(Z/N(i)Z) |
---|
| 811 | number m,q; // m=|E(Z/N(i)Z)| and q|m |
---|
| 812 | number a,b,j,c; // characterize E(Z/N(i)Z) |
---|
| 813 | number g,u; // g out of Z/N(i)Z, u=Jacobi(g,N(i)) |
---|
[3eadab] | 814 | poly T; // T=HilbertClassPoly(D,K) |
---|
[d1b0065] | 815 | matrix M; // M contains the coefficients of T |
---|
| 816 | |
---|
| 817 | if(printlevel>=1) {"Liste H der moeglichen geeigneten Diskriminanten wird berechnet.";} |
---|
| 818 | H=disc(N,K/2); |
---|
| 819 | if(printlevel>=1) {"H="+string(H);pause();} |
---|
| 820 | |
---|
| 821 | int step=2; |
---|
| 822 | while(1) |
---|
| 823 | { |
---|
| 824 | if(step==2) // (2)[Is N(i) small??] |
---|
[370344] | 825 | { |
---|
[d1b0065] | 826 | L=5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997; |
---|
[2472afe] | 827 | for(j(0)=1;j(0)<=size(L);j(0)++) |
---|
[d1b0065] | 828 | { |
---|
[3d4a5a] | 829 | if(N(i)==L[j(0)]){return(1);} |
---|
[d1b0065] | 830 | if(((N(i) mod L[j(0)])==0)&&(N(i)!=L[j(0)])) |
---|
| 831 | { |
---|
| 832 | if(printlevel>=1) {"N("+string(i)+")="+string(N(i))+" ist durch "+string(L[j(0)])+" teilbar.";pause();} |
---|
| 833 | step=14; |
---|
| 834 | break; |
---|
| 835 | } |
---|
| 836 | } |
---|
| 837 | if(step==2) |
---|
[370344] | 838 | { |
---|
[d1b0065] | 839 | step=3; |
---|
[370344] | 840 | } |
---|
| 841 | } |
---|
[449fbf] | 842 | |
---|
[d1b0065] | 843 | if(step==3) // (3)[Choose next discriminant] |
---|
| 844 | { |
---|
| 845 | n(i)=n(i)+1; |
---|
| 846 | if(n(i)==size(H)+1) |
---|
| 847 | { |
---|
| 848 | if(printlevel>=1) {"Algorithmus nicht anwendbar, da zu wenige geeignete Diskriminanten existieren."; |
---|
| 849 | "Erhoehe den Genauigkeitsparameter K und starte den Algorithmus erneut.";pause();} |
---|
| 850 | return(0); |
---|
| 851 | } |
---|
| 852 | D=H[n(i)]; |
---|
| 853 | if(printlevel>=1) {"Naechste Diskriminante D wird gewaehlt. D="+string(D)+".";pause();} |
---|
| 854 | if(Jacobi(D,N(i))!=1) |
---|
| 855 | { |
---|
| 856 | if(printlevel>=1) {"Jacobi(D,N("+string(i)+"))="+string(Jacobi(D,N(i)));pause();} |
---|
| 857 | continue; |
---|
| 858 | } |
---|
| 859 | else |
---|
| 860 | { |
---|
| 861 | L1=CornacchiaModified(D,N(i)); |
---|
| 862 | if(size(L1)>1) |
---|
| 863 | { |
---|
| 864 | if(printlevel>=1) {"Die Loesung (x,y) der Gleichung x^2+|D|y^2=4N("+string(i)+") lautet";L1;pause();} |
---|
| 865 | step=4; |
---|
| 866 | } |
---|
| 867 | else |
---|
| 868 | { |
---|
| 869 | if(L1[1]==-1) |
---|
[370344] | 870 | { |
---|
[d1b0065] | 871 | if(printlevel>=1) {"Die Gleichung x^2+|D|y^2=4N("+string(i)+") hat keine Loesung.";pause();} |
---|
| 872 | continue; |
---|
| 873 | } |
---|
| 874 | if(L1[1]==0) |
---|
| 875 | { |
---|
[2472afe] | 876 | if(printLevel>=1) {"Algorithmus fuer N("+string(i)+")="+string(N(i))+" nicht anwendbar,"; |
---|
[d1b0065] | 877 | "da zu wenige geeignete Diskriminanten existieren.";pause();} |
---|
| 878 | step=14; |
---|
| 879 | } |
---|
| 880 | } |
---|
| 881 | } |
---|
| 882 | } |
---|
[449fbf] | 883 | |
---|
[d1b0065] | 884 | if(step==4) // (4)[Factor m] |
---|
| 885 | { |
---|
| 886 | if(printlevel>=1) {"Die Liste L2 der moeglichen m=|E(Z/N("+string(i)+")Z)| wird berechnet.";} |
---|
| 887 | if(absValue(L1[1])^2<=4*N(i)) {L2=N(i)+1+L1[1],N(i)+1-L1[1];} |
---|
| 888 | if(D==-4) |
---|
| 889 | { |
---|
| 890 | if(absValue(2*L1[2])^2<=4*N(i)) {L2[size(L2)+1]=N(i)+1+2*L1[2]; |
---|
| 891 | L2[size(L2)+1]=N(i)+1-2*L1[2];} |
---|
| 892 | } |
---|
| 893 | // An dieser Stelle wurde "<=4*N(i)" durch "<=16*N(i)" ersetzt. |
---|
| 894 | if(D==-3) |
---|
| 895 | { |
---|
| 896 | if(absValue(L1[1]+3*L1[2])^2<=16*N(i)) {L2[size(L2)+1]=N(i)+1+(L1[1]+3*L1[2])/2; |
---|
| 897 | L2[size(L2)+1]=N(i)+1-(L1[1]+3*L1[2])/2;} |
---|
| 898 | if(absValue(L1[1]-3*L1[2])^2<=16*N(i)) {L2[size(L2)+1]=N(i)+1+(L1[1]-3*L1[2])/2; |
---|
| 899 | L2[size(L2)+1]=N(i)+1-(L1[1]-3*L1[2])/2;} |
---|
| 900 | } |
---|
| 901 | /////////////////////////////////////////////////////////////// |
---|
| 902 | if(size(L2)==0) |
---|
| 903 | { |
---|
| 904 | if(printlevel>=1) {"Nach dem Satz von Hasse wurden keine moeglichen m=|E(Z/N("+string(i)+")Z)|"; |
---|
| 905 | "fuer D="+string(D)+" gefunden.";} |
---|
| 906 | step=3; |
---|
| 907 | continue; |
---|
| 908 | } |
---|
| 909 | else |
---|
| 910 | { |
---|
| 911 | if(printlevel>=1) {"L2=";L2;pause();} |
---|
| 912 | } |
---|
[449fbf] | 913 | |
---|
[d1b0065] | 914 | if(printlevel>=1) {"Die Liste S der Faktoren aller moeglichen m wird berechnet.";} |
---|
| 915 | S=list(); |
---|
| 916 | for(j(1)=1;j(1)<=size(L2);j(1)++) |
---|
| 917 | { |
---|
| 918 | m=L2[j(1)]; |
---|
| 919 | if(m!=0) |
---|
| 920 | { |
---|
| 921 | S1=PollardRho(m,10000,1,L); |
---|
| 922 | S2=pFactor(m,100,L); |
---|
| 923 | S[size(S)+1]=list(m,S1+S2); |
---|
| 924 | } |
---|
| 925 | } |
---|
| 926 | if(printlevel>=1) {"S=";S;pause();} |
---|
| 927 | step=5; |
---|
| 928 | } |
---|
[449fbf] | 929 | |
---|
[d1b0065] | 930 | if(step==5) // (5)[Does a suitable m exist??] |
---|
| 931 | { |
---|
| 932 | for(j(2)=1;j(2)<=size(S);j(2)++) |
---|
| 933 | { |
---|
| 934 | m=L2[j(2)]; |
---|
| 935 | for(j(3)=1;j(3)<=size(S[j(2)][2]);j(3)++) |
---|
| 936 | { |
---|
| 937 | q=S[j(2)][2][j(3)]; |
---|
| 938 | // sqr(sqr(N(i),50),50) ersetzt intRoot(intRoot(N(i))) |
---|
| 939 | if((q>(sqr(sqr(N(i),50),50)+1)^2) && (MillerRabin(q,5)==1)) |
---|
| 940 | { |
---|
| 941 | step=6; |
---|
| 942 | break; |
---|
| 943 | } |
---|
| 944 | ////////////////////////////////////////////////////// |
---|
| 945 | } |
---|
| 946 | if(step==6) |
---|
| 947 | { |
---|
| 948 | if(printlevel>=1) {"Geeignetes Paar (m,q) gefunden, so dass q|m,"; |
---|
| 949 | "q>(4-th root(N("+string(i)+"))+1)^2 und q den Miller-Rabin-Test passiert."; |
---|
| 950 | "m="+string(m)+",";"q="+string(q);pause();} |
---|
| 951 | break; |
---|
| 952 | } |
---|
| 953 | else |
---|
| 954 | { |
---|
| 955 | step=3; |
---|
| 956 | } |
---|
| 957 | } |
---|
| 958 | if(step==3) |
---|
| 959 | { |
---|
| 960 | if(printlevel>=1) {"Kein geeignetes Paar (m,q), so dass q|m,"; |
---|
| 961 | "q>(4-th root(N("+string(i)+"))+1)^2 und q den Miller-Rabin-Test passiert, gefunden."; |
---|
| 962 | pause();} |
---|
| 963 | continue; |
---|
| 964 | } |
---|
| 965 | } |
---|
[449fbf] | 966 | |
---|
[d1b0065] | 967 | if(step==6) // (6)[Compute elliptic curve] |
---|
| 968 | { |
---|
| 969 | if(D==-4) |
---|
| 970 | { |
---|
| 971 | a=-1; |
---|
| 972 | b=0; |
---|
| 973 | if(printlevel>=1) {"Da D=-4, setze a=-1 und b=0.";pause();} |
---|
| 974 | } |
---|
| 975 | if(D==-3) |
---|
| 976 | { |
---|
| 977 | a=0; |
---|
| 978 | b=-1; |
---|
| 979 | if(printlevel>=1) {"Da D=-3, setze a=0 und b=-1.";pause();} |
---|
| 980 | } |
---|
| 981 | if(D<-4) |
---|
| 982 | { |
---|
| 983 | if(printlevel>=1) {"Das Minimalpolynom T von j((D+sqr(D))/2) aus Z[X] fuer D="+string(D)+" wird berechnet.";} |
---|
[3eadab] | 984 | T=HilbertClassPoly(D,K); |
---|
[d1b0065] | 985 | if(printlevel>=1) {"T="+string(T);pause();} |
---|
| 986 | |
---|
| 987 | M=coeffs(T,var(1)); |
---|
| 988 | T=0; |
---|
| 989 | |
---|
| 990 | for(j(4)=1;j(4)<=nrows(M);j(4)++) |
---|
| 991 | { |
---|
| 992 | M[j(4),1]=leadcoef(M[j(4),1]) mod N(i); |
---|
| 993 | T=T+M[j(4),1]*var(1)^(j(4)-1); |
---|
| 994 | } |
---|
| 995 | if(printlevel>=1) {"Setze T=T mod N("+string(i)+").";"T="+string(T);pause();} |
---|
| 996 | |
---|
[3eadab] | 997 | R=rootsModp(int(N(i)),T); |
---|
[d1b0065] | 998 | if(deg(T)>size(R)) |
---|
| 999 | { |
---|
| 1000 | ERROR("Das Polynom T zerfaellt modulo N("+string(i)+") nicht vollstaendig in Linearfaktoren." |
---|
| 1001 | "Erhoehe den Genauigkeitsparameter K und starte den Algorithmus erneut."); |
---|
[2472afe] | 1002 | } |
---|
[d1b0065] | 1003 | if(printlevel>=1) {if(deg(T)>1) {"Die "+string(deg(T))+" Nullstellen von T modulo N("+string(i)+") sind"; |
---|
| 1004 | R;pause();} |
---|
| 1005 | if(deg(T)==1){"Die Nullstelle von T modulo N("+string(i)+") ist";R;pause();}} |
---|
| 1006 | |
---|
| 1007 | j=R[1]; |
---|
| 1008 | c=j*exgcdN(j-1728,N(i))[1]; |
---|
| 1009 | a=-3*c mod N(i); |
---|
| 1010 | b=2*c mod N(i); |
---|
| 1011 | if(printlevel>=1) {"Waehle die Nullstelle j="+string(j)+" aus und setze";"c=j/(j-1728) mod N("+string(i)+"), a=-3c mod N("+string(i)+"), b=2c mod N("+string(i)+")."; |
---|
| 1012 | "a="+string(a)+",";"b="+string(b);pause();} |
---|
| 1013 | } |
---|
| 1014 | step=7; |
---|
| 1015 | } |
---|
[449fbf] | 1016 | |
---|
[d1b0065] | 1017 | if(step==7) // (7)[Find g] |
---|
| 1018 | { |
---|
| 1019 | if(D==-3) |
---|
| 1020 | { |
---|
| 1021 | while(1) |
---|
| 1022 | { |
---|
| 1023 | g=random(1,2147483647) mod N(i); |
---|
| 1024 | u=Jacobi(g,N(i)); |
---|
| 1025 | if((u==-1)&&(powerN(g,(N(i)-1)/3,N(i))!=1)) |
---|
| 1026 | { |
---|
| 1027 | if(printlevel>=1) {"g="+string(g);pause();} |
---|
| 1028 | break; |
---|
| 1029 | } |
---|
| 1030 | } |
---|
| 1031 | } |
---|
| 1032 | else |
---|
| 1033 | { |
---|
| 1034 | while(1) |
---|
| 1035 | { |
---|
| 1036 | g=random(1,2147483647) mod N(i); |
---|
| 1037 | u=Jacobi(g,N(i)); |
---|
| 1038 | if(u==-1) |
---|
| 1039 | { |
---|
| 1040 | if(printlevel>=1) {"g="+string(g);pause();} |
---|
| 1041 | break; |
---|
| 1042 | } |
---|
| 1043 | } |
---|
| 1044 | } |
---|
| 1045 | step=8; |
---|
| 1046 | } |
---|
[449fbf] | 1047 | |
---|
[d1b0065] | 1048 | if(step==8) // (8)[Find P] |
---|
| 1049 | { |
---|
| 1050 | if(printlevel>=1) {"Ein zufaelliger Punkt P auf der Elliptischen Kurve"; |
---|
| 1051 | "mit der Gleichung y^2=x^3+ax+b fuer";"N("+string(i)+")="+string(N(i))+","; |
---|
| 1052 | " a="+string(a)+",";" b="+string(b);"wird gewaehlt.";} |
---|
| 1053 | P=ellipticRandomPoint(N(i),a,b); |
---|
| 1054 | if(printlevel>=1) {"P=("+string(P)+")";pause();} |
---|
[449fbf] | 1055 | |
---|
[d1b0065] | 1056 | if(size(P)==1) |
---|
| 1057 | { |
---|
| 1058 | step=14; |
---|
| 1059 | } |
---|
| 1060 | else |
---|
| 1061 | { |
---|
| 1062 | step=9; |
---|
| 1063 | } |
---|
| 1064 | } |
---|
[449fbf] | 1065 | |
---|
[d1b0065] | 1066 | if(step==9) // (9)[Find right curve] |
---|
| 1067 | { |
---|
| 1068 | if(printlevel>=1) {"Die Punkte P2=(m/q)*P und P1=q*P2 auf der Kurve werden berechnet.";} |
---|
| 1069 | P2=ellipticMult(N(i),a,b,P,m/q); |
---|
| 1070 | P1=ellipticMult(N(i),a,b,P2,q); |
---|
| 1071 | if(printlevel>=1) {"P1=("+string(P1)+"),";"P2=("+string(P2)+")";pause();} |
---|
[449fbf] | 1072 | |
---|
[d1b0065] | 1073 | if((P1[1]==0)&&(P1[2]==1)&&(P1[3]==0)) |
---|
| 1074 | { |
---|
| 1075 | step=12; |
---|
| 1076 | } |
---|
| 1077 | else |
---|
| 1078 | { |
---|
| 1079 | if(printlevel>=1) {"Da P1!=(0:1:0), ist fuer die Koeffizienten a="+string(a)+" und b="+string(b)+" m!=|E(Z/N("+string(i)+")Z)|."; |
---|
| 1080 | "Waehle daher neue Koeffizienten a und b.";pause();} |
---|
| 1081 | step=10; |
---|
| 1082 | } |
---|
| 1083 | } |
---|
[449fbf] | 1084 | |
---|
[2472afe] | 1085 | if(step==10) // (10)[Change coefficients] |
---|
[d1b0065] | 1086 | { |
---|
| 1087 | k=k+1; |
---|
[3eadab] | 1088 | if(k>=wUnit(D)) |
---|
[d1b0065] | 1089 | { |
---|
[3eadab] | 1090 | if(printlevel>=1) {"Da k=wUnit(D)="+string(k)+", ist N("+string(i)+")="+string(N(i))+" nicht prim.";pause();} |
---|
[d1b0065] | 1091 | step=14; |
---|
| 1092 | } |
---|
| 1093 | else |
---|
| 1094 | { |
---|
| 1095 | if(D<-4) {a=a*g^2 mod N(i); b=b*g^3 mod N(i); |
---|
| 1096 | if(printlevel>=1) {"Da D<-4, setze a=a*g^2 mod N("+string(i)+") und b=b*g^3 mod N("+string(i)+")."; |
---|
| 1097 | "a="+string(a)+",";"b="+string(b)+",";"k="+string(k);pause();}} |
---|
| 1098 | if(D==-4){a=a*g mod N(i); |
---|
| 1099 | if(printlevel>=1) {"Da D=-4, setze a=a*g mod N("+string(i)+").";"a="+string(a)+","; |
---|
| 1100 | "b="+string(b)+",";"k="+string(k);pause();}} |
---|
| 1101 | if(D==-3){b=b*g mod N(i); |
---|
| 1102 | if(printlevel>=1) {"Da D=-3, setze b=b*g mod N("+string(i)+").";"a="+string(a)+","; |
---|
| 1103 | "b="+string(b)+",";"k="+string(k);pause();}} |
---|
| 1104 | step=8; |
---|
| 1105 | continue; |
---|
| 1106 | } |
---|
| 1107 | } |
---|
[449fbf] | 1108 | |
---|
[d1b0065] | 1109 | if(step==11) // (11)[Find a new P] |
---|
| 1110 | { |
---|
| 1111 | if(printlevel>=1) {"Ein neuer zufaelliger Punkt P auf der Elliptischen Kurve wird gewaehlt,"; |
---|
| 1112 | "da auch P2=(0:1:0).";} |
---|
| 1113 | P=ellipticRandomPoint(N(i),a,b); |
---|
| 1114 | if(printlevel>=1) {"P=("+string(P)+")";pause();} |
---|
[449fbf] | 1115 | |
---|
[d1b0065] | 1116 | if(size(P)==1) |
---|
| 1117 | { |
---|
| 1118 | step=14; |
---|
| 1119 | } |
---|
| 1120 | else |
---|
| 1121 | { |
---|
| 1122 | if(printlevel>=1) {"Die Punkte P2=(m/q)*P und P1=q*P2 auf der Kurve werden berechnet.";} |
---|
| 1123 | P2=ellipticMult(N(i),a,b,P,m/q); |
---|
| 1124 | P1=ellipticMult(N(i),a,b,P2,q); |
---|
| 1125 | if(printlevel>=1) {"P1=("+string(P1)+"),";"P2=("+string(P2)+")";pause();} |
---|
| 1126 | |
---|
| 1127 | if((P1[1]!=0)||(P1[2]!=1)||(P1[3]!=0)) |
---|
| 1128 | { |
---|
| 1129 | if(printlevel>=1) {"Da P1!=(0:1:0), ist, fuer die Koeffizienten a="+string(a)+" und b="+string(b)+", m!=|E(Z/N("+string(i)+")Z)|."; |
---|
| 1130 | "Waehle daher neue Koeffizienten a und b.";pause();} |
---|
| 1131 | step=10; |
---|
| 1132 | continue; |
---|
| 1133 | } |
---|
| 1134 | else |
---|
| 1135 | { |
---|
| 1136 | step=12; |
---|
| 1137 | } |
---|
| 1138 | } |
---|
| 1139 | } |
---|
[449fbf] | 1140 | |
---|
[d1b0065] | 1141 | if(step==12) // (12)[Check P] |
---|
| 1142 | { |
---|
| 1143 | if((P2[1]==0)&&(P2[2]==1)&&(P2[3]==0)) |
---|
| 1144 | { |
---|
| 1145 | step=11; |
---|
| 1146 | continue; |
---|
| 1147 | } |
---|
| 1148 | else |
---|
| 1149 | { |
---|
| 1150 | step=13; |
---|
| 1151 | } |
---|
| 1152 | } |
---|
[449fbf] | 1153 | |
---|
[d1b0065] | 1154 | if(step==13) // (13)[Recurse] |
---|
| 1155 | { |
---|
| 1156 | if(i<B) |
---|
| 1157 | { |
---|
| 1158 | if(printlevel>=1) {string(i+1)+". Rekursion:";""; |
---|
| 1159 | "N("+string(i)+")="+string(N(i))+" erfuellt die Bedingungen des zugrunde liegenden Satzes,"; |
---|
| 1160 | "da P1=(0:1:0) und P2[3] aus (Z/N("+string(i)+")Z)*.";""; |
---|
| 1161 | "Untersuche nun, ob auch der gefundene Faktor q="+string(q)+" diese Bedingungen erfuellt."; |
---|
| 1162 | "Setze dazu i=i+1, N("+string(i+1)+")=q="+string(q)+" und beginne den Algorithmus von vorne.";pause();} |
---|
| 1163 | i=i+1; |
---|
| 1164 | int n(i); |
---|
| 1165 | number N(i)=q; |
---|
| 1166 | k=0; |
---|
| 1167 | step=2; |
---|
| 1168 | continue; |
---|
| 1169 | } |
---|
| 1170 | else |
---|
| 1171 | { |
---|
| 1172 | if(printlevel>=1) {"N(B)=N("+string(i)+")="+string(N(i))+" erfuellt die Bedingungen des zugrunde liegenden Satzes,"; |
---|
| 1173 | "da P1=(0:1:0) und P2[3] aus (Z/N("+string(i)+")Z)*."; |
---|
| 1174 | "Insbesondere ist N="+string(N)+" prim.";pause();} |
---|
| 1175 | return(1); |
---|
| 1176 | } |
---|
| 1177 | } |
---|
[370344] | 1178 | |
---|
[d1b0065] | 1179 | if(step==14) // (14)[Backtrack] |
---|
| 1180 | { |
---|
| 1181 | if(i>0) |
---|
| 1182 | { |
---|
[2472afe] | 1183 | if(printlevel>=1) {"Setze i=i-1 und starte den Algorithmus fuer N("+string(i-1)+")="+string(N(i-1))+" mit"; |
---|
[d1b0065] | 1184 | "neuer Diskriminanten von vorne.";pause();} |
---|
| 1185 | i=i-1; |
---|
| 1186 | k=0; |
---|
| 1187 | step=3; |
---|
| 1188 | } |
---|
| 1189 | else |
---|
| 1190 | { |
---|
[3eadab] | 1191 | if(printlevel>=1) {"N(0)=N="+string(N)+" und daher ist N nicht prim.";pause(n);} |
---|
[d1b0065] | 1192 | return(-1); |
---|
| 1193 | } |
---|
| 1194 | } |
---|
| 1195 | } |
---|
| 1196 | } |
---|
[53e03a6] | 1197 | } |
---|
[449fbf] | 1198 | example |
---|
[53e03a6] | 1199 | { "EXAMPLE:"; echo = 2; |
---|
[449fbf] | 1200 | ring R = 0,x,dp; |
---|
| 1201 | printlevel=1; |
---|
| 1202 | Atkin(7691,100,5); |
---|
| 1203 | Atkin(10000079,100,2); |
---|
[53e03a6] | 1204 | } |
---|
[3eadab] | 1205 | |
---|