Changeset 430001 in git


Ignore:
Timestamp:
Apr 1, 2005, 1:53:51 PM (19 years ago)
Author:
Hans Schönemann <hannes@…>
Branches:
(u'fieker-DuVal', '117eb8c30fc9e991c4decca4832b1d19036c4c65')(u'spielwiese', 'b52fc4b2495505785981d640dcf7eb3e456778ef')
Children:
b35957136da5112ff808d992650669df3de03943
Parents:
24beed45804e9298a0238cd2373865d057e1f77e
Message:
*pfister: preimageLoc


git-svn-id: file:///usr/local/Singular/svn/trunk@7806 2c84dea3-7e68-4137-9b89-c4e89433aadc
File:
1 edited

Legend:

Unmodified
Added
Removed
  • Singular/LIB/ring.lib

    r24beed r430001  
    11//(GMG, last modified 03.11.95)
    22///////////////////////////////////////////////////////////////////////////////
    3 version="$Id: ring.lib,v 1.18 2004-04-20 15:55:22 Singular Exp $";
     3version="$Id: ring.lib,v 1.19 2005-04-01 11:53:31 Singular Exp $";
    44category="General purpose";
    55info="
     
    2020 ringtensor(\"R\",s,t,..);create ring R, tensor product of rings s,t,...
    2121 ringweights(r);          intvec of weights of ring variables of ring r
     22 preimageLoc(R,phi,Q)     computes preimage for non-global orderings
    2223             (parameters in square brackets [] are optional)
    2324";
     
    786787}
    787788///////////////////////////////////////////////////////////////////////////////
     789proc preimageLoc(string R_name,string phi_name,string Q_name )
     790"SYNTAX: @code{preimageLoc (} ring_name, map_name, ideal_name  @code{)}
     791        all input parameters of type string
     792TYPE:    ideal
     793PURPOSE: computes the preimage of an ideal under a given map for non-global
     794         orderings.
     795         The second argument has to be the name of a map from the basering to
     796         the given ring (or the name of an ideal defining such a map), and
     797         the ideal has to be an ideal in the given ring.
     798SEE ALSO: preimage
     799KEYWORDS:
     800EXAMPLE: example preimageLoc ; shows an example"
     801{
     802  def S=basering;
     803  int i;
     804  string newRing,minpoly_string;
     805  if(attrib(S,"global")!=1)
     806  {
     807    if(typeof(S)=="qring")
     808    {
     809      ideal I=ideal(S);
     810      newRing="ring S0=("+charstr(S)+"),("+varstr(S)+"),dp;";
     811      minpoly_string=string(minpoly);
     812      execute(newRing);
     813      execute("minpoly="+minpoly_string+";");
     814      ideal I=imap(S,I);
     815      list pr=primdecGTZ(I);
     816      newRing="ring SL=("+charstr(S)+"),("+varstr(S)+"),("+ordstr(S)+");";
     817      execute(newRing);
     818      execute("minpoly="+minpoly_string+";");
     819      list pr=imap(S0,pr);
     820      ideal I0=std(pr[1][1]);
     821      for(i=2;i<=size(pr);i++)
     822      {
     823         I0=intersect(I0,std(pr[i][1]));
     824      }
     825      setring S0;
     826      ideal I0=imap(SL,I0);
     827      qring S1=std(I0);
     828    }
     829    else
     830    {
     831      def S1=S;
     832    }
     833  }
     834  else
     835  {
     836    def S1=S;
     837  }
     838  def @R=`R_name`;
     839  setring @R;
     840  def @phi=`phi_name`;
     841  ideal phiId=ideal(@phi);
     842  def Q=`Q_name`;
     843  if(attrib(@R,"global")!=1)
     844  {
     845    if(typeof(@R)=="qring")
     846    {
     847      ideal J=ideal(@R);
     848      newRing="ring R0=("+charstr(@R)+"),("+varstr(@R)+"),dp;";
     849      minpoly_string=string(minpoly);
     850      execute(newRing);
     851      execute("minpoly="+minpoly_string+";");
     852      ideal J=imap(@R,J);
     853      list pr=primdecGTZ(J);
     854      newRing="ring RL=("+charstr(@R)+"),("+varstr(@R)+"),("+ordstr(@R)+");";
     855      execute(newRing);
     856      execute("minpoly="+minpoly_string+";");
     857      list pr=imap(R0,pr);
     858      ideal J0=std(pr[1][1]);
     859      for(i=2;i<=size(pr);i++)
     860      {
     861         J0=intersect(J0,std(pr[i][1]));
     862      }
     863      setring R0;
     864      ideal J0=imap(RL,J0);
     865      qring R1=std(J0);
     866      ideal Q=imap(@R,Q);
     867      map @phi=S1,imap(@R,phiId);
     868    }
     869    else
     870    {
     871      def R1=@R;
     872    }
     873  }
     874  else
     875  {
     876    def R1=@R;
     877  }
     878  setring S1;
     879  ideal preQ=preimage(R1,@phi,Q);
     880  setring S;
     881  ideal prQ=imap(S1,preQ);
     882  return(prQ);
     883}
     884example
     885{ "EXAMPLE:"; echo=2;
     886  ring S =0,(x,y,z),dp;
     887  ring R0=0,(x,y,z),ds;
     888  qring R=std(x+x2);
     889  map psi=S,x,y,z;
     890  ideal null;
     891  setring S;
     892  ideal nu=preimageLoc("R","psi","null");
     893  nu;
     894}
     895
Note: See TracChangeset for help on using the changeset viewer.