Changeset edfd36 in git for Singular/LIB/signcond.lib


Ignore:
Timestamp:
May 6, 2005, 1:17:33 PM (18 years ago)
Author:
Hans Schönemann <hannes@…>
Branches:
(u'spielwiese', '8e0ad00ce244dfd0756200662572aef8402f13d5')
Children:
7acf9bf2b74329722c5db8dcbfad38aefc35a663
Parents:
6ed9240d0e05977f97c2c93af491078329ba7b6d
Message:
*GMG: help


git-svn-id: file:///usr/local/Singular/svn/trunk@8063 2c84dea3-7e68-4137-9b89-c4e89433aadc
File:
1 edited

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  • Singular/LIB/signcond.lib

    r6ed924 redfd36  
    1 // $Id: signcond.lib,v 1.2 2005-05-02 12:24:16 Singular Exp $
     1// $Id: signcond.lib,v 1.3 2005-05-06 11:17:33 Singular Exp $
    22// E. Tobis  12.Nov.2004
    33// last change 16. Apr. 2005 (G.-M. Greuel)
     
    1414
    1515PROCEDURES:
    16   signcnd(P,I)   The sign conditions realized the polynomials of P on a V(I)
     16  signcnd(P,I)   The sign conditions realized by polynomials of P on a V(I)
    1717  psigncnd(P,l)  Pretty prints the output of signcnd (l)
    1818  firstoct(I)    The number of elements of V(I) with every coordinate > 0
     
    2727proc firstoct(ideal I)
    2828"USAGE:    firstoct(i); i ideal
    29 RETURN:   number: the number of points of V(i) lying in the first orthant
     29RETURN:   number: the number of points of V(i) lying in the first octant
    3030ASSUME:   i is a Groebner basis
    3131SEE ALSO: signcnd
     
    7070
    7171proc signcnd(ideal P,ideal I)
    72 "USAGE:     signcnd(P,i); ideal P,i. i must be a grobner basis
     72"USAGE:     signcnd(P,I); ideal P,I
    7373RETURN:    list: the sign conditions realized by the polynomials of P on V(I).
    74            See the example for an explanation of the output.
    75 SEE ALSO:  firstoct
     74           The output of signcnd is a list of two lists. Both lists have the
     75           same length. That length is the number of sign conditions realized
     76           by the polynomials of P on the set V(i).
     77           Each element of the first list indicates a sign condition of the
     78           polynomials of P.
     79           Each element of the second list indicates how many elements of V(I)
     80           give rise to the sign condition expressed by the same position on
     81           the first list.
     82           See the example for further explanation of the output.
     83ASSUME:    I is a Groebner basis
     84NOTE:      The procedure psigncnd performs some pretty printing of this output
     85SEE ALSO:  firstoct, psigncnd
    7686EXAMPLE:   example signcnd; shows an example"
    7787{
     
    242252}
    243253example
    244 {
    245   echo = 2;
     254{ echo = 2;
    246255  ring r = 0,(x,y),dp;
    247256  ideal i = (x-2)*(x+3)*x,y*(y-1);
    248257  ideal P = x,y;
    249258  list l = signcnd(P,i);
    250   echo = 0;
    251 
    252   print("The output of signcnd is a list of two lists. Both lists have the
    253 same");
    254   print("length. That length is the number of sign conditions realized by the");
    255   print ("polynomials of P on the set V(i). In this example, that number
    256 is");
    257   print("print(size(l[1]));");
    258   print(size(l[1]));
    259   print("Each element of the first list indicates a sign condition of the");
    260   print("polynomials of P. For example,");
    261   print("print(l[1][2]);");
    262   print(l[1][2]);
    263   print("means P[1] > 0,P[2] = 0");
    264   print("Each element of the second list indicates how many elements of V(I)");
    265   print("give rise to the sign condition expressed by the same position on the");
    266   print("first list. For example");
    267   print("print(l[2][2]);");
    268   print(l[2][2]);
    269   print("indicates that exactly 1 elemnt of V(I) gives rise to the condition");
    270   print("P[1] > 0,P[2] = 0.");
    271   print("The procedure psigncnd performs some pretty printing on this output.");
     259
     260  size(l[1]);     // = the number of sign conditions of P on V(i)
     261
     262  //Each element of l[1] indicates a sign condition of the polynomials of P.
     263  //The following means P[1] > 0, P[2] = 0:
     264  l[1][2];
     265
     266  //Each element of l[2] indicates how many elements of V(I) give rise to
     267  //the sign condition expressed by the same position on the first list.
     268  //The following means that exactly 1 element of V(I) gives rise to the
     269  //condition P[1] > 0, P[2] = 0:
     270  l[2][2];
    272271}
    273272///////////////////////////////////////////////////////////////////////////////
    274273
    275274proc psigncnd(ideal P,list l)
    276 "USAGE:     psigncnd(P,I); ideal P, list l
     275"USAGE:     psigncnd(P,l); ideal P, list l
    277276RETURN:    list: a formatted version of l
    278277SEE ALSO:  signcnd
     
    438437///////////////////////////////////////////////////////////////////////////////
    439438
     439
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