Changeset 8f4b23 in git for Singular

Timestamp:

May 19, 2005, 3:32:35 PM (19 years ago)

Author:

Hans Schönemann <hannes@…>

Branches:

(u'fieker-DuVal', '117eb8c30fc9e991c4decca4832b1d19036c4c65')(u'spielwiese', 'd08f5f0bb3329b8ca19f23b74cb1473686415c3a')

Children:

5c1cb7f29d5ce62aa91dc921b7cb8f34a92fe883

Parents:

cc5e38df80c917c52275aa45b1835bb4f86a0f7f

Message:

*lossen: sres option


git-svn-id: file:///usr/local/Singular/svn/trunk@8241 2c84dea3-7e68-4137-9b89-c4e89433aadc

Location:

Singular/LIB

Files:

• homolog.lib (modified) (7 diffs)
• sheafcoh.lib (modified) (5 diffs)

Singular/LIB/homolog.lib

@@ -1 +1 @@
 ///////////////////////////////////////////////////////////////////////////////
-version="$Id: homolog.lib,v 1.17 2005-05-18 15:59:37 Singular Exp $";
+version="$Id: homolog.lib,v 1.18 2005-05-19 13:32:35 Singular Exp $";
 category="Commutative Algebra";
 info="
@@ -465 +465 @@
 DISPLAY: printlevel >=0: (affine) dimension of Ext^k for each k  (default)
          printlevel >=1: Ak, Ak+1 and kbase of Ext^k in Fk*
-NOTE:    In order to compute Ext^k(M,R) use the command Ext_R(k,syz(M));
-         If the attribute \"isHomog\" has been set for the input module, it 
+NOTE:    In order to compute Ext^k(M,R) use the command Ext_R(k,syz(M));@*
+         By default, the procedure uses the @code{mres} command. If called 
+         with the additional parameter @code{\"sres\"}, the @code{sres} command
+         is used instead.@*
+         If the attribute @code{\"isHomog\"} has been set for the input module, it 
          is also set for the returned module (accordingly). 
 EXAMPLE: example Ext_R; shows an example
@@ -478 +481 @@
   intvec weightR,ww;
   if ( typeof(attrib(M,"isHomog"))!="string" )
-  {  
+  { 
+    weightR=attrib(M,"isHomog"); 
     withWeight=1;
   }
@@ -486 +490 @@
   vector leadCol;
   matrix kb;
+  module G;
   list L1,L2,L3,L,K;
-  resolution resl,resm2;
+  resolution resm2;
   int j,k,max,ii,t1,t2,di,leadComp,shift;
   intvec A1,A2,A3;
@@ -497 +502 @@
   for( ii=1; ii<=size(#); ii++ )
   {
-    t2=1; // return a list if t2=1
-    if ( (typeof(#[ii])=="string") and (withWeight==0) )
-    { // NOTE: at this writing, sres does not return weights
-      if ( #[ii]=="sres" ) { t1=1; t2=0; } // use sres instead of mres if t1=1
+    if (typeof(#[ii])=="int") { // return a list if t2=1
+      t2=1; 
+    }
+    else {
+      if (typeof(#[ii])=="string") { 
+        // NOTE: at this writing, sres does not return weights
+        if ( #[ii]=="sres" ) { t1=1; } // use sres instead of mres if t1=1
+      }
     }
   }
@@ -523 +532 @@
   }
   if( t1==1 )
-  {
+  { // compute resolution via sres command
     if( attrib(M,"isSB")==0 ) { M=std(M); }
-    resl = sres(M,max+1);
-  }
-  else { resl = mres(M,max+1); }
+    list resl = sres(M,max+1);
+    if (withWeight) { 
+      // **** at this writing, sres does not return weights, we try to
+      // **** compute them via homog for each syzygy module  
+      attrib(resl,"isHomog",weightR);
+      G=resl[1];
+      attrib(G,"isHomog",weightR);
+      resl[1]=G;
+      for (j=2; j<=size(resl); j++) {
+        if (size(resl[j])!=0) {
+          ww=0;
+          for (k=1; k<=ncols(G); k++) {
+            leadCol = leadmonom(G[k]);
+            leadComp = nrows(leadCol);
+            ww[k] = deg(leadCol)+weightR[leadComp];
+          }
+          G=resl[j];
+          attrib(G,"isHomog",ww);
+          resl[j]=G;          
+          weightR=ww;
+        }
+      }
+    }
+  }
+  else { resolution resl = mres(M,max+1); }
   for( ii=1; ii<=s; ii++ )
   {
@@ -571 +602 @@
         attrib(m2t,"isHomog",weightR);
         // --------------------------------------------------------------------
+        ww=0;
         for (j=1; j<=nrows(m2); j++) {
           leadCol = leadmonom(m2t[j]);

Singular/LIB/sheafcoh.lib

@@ -1 +1 @@
 S///////////////////////////////////////////////////////////////////////////////
-version="$Id: sheafcoh.lib,v 1.4 2005-05-19 08:14:51 Singular Exp $";
+version="$Id: sheafcoh.lib,v 1.5 2005-05-19 13:32:35 Singular Exp $";
 category="Commutative Algebra";
 info="
@@ -383 +383 @@
 ///////////////////////////////////////////////////////////////////////////////
 
-proc sheafCoh(module M,int l,int h)
+proc sheafCoh(module M,int l,int h,list #)
 "USAGE:   sheafCoh(M,l,h);    M module, l,h int 
 ASSUME:  @code{M} is graded and is either 0 or comes assigned with an 
@@ -405 +405 @@
 NOTE:    The procedure is based on local duality as described in [Eisenbud:
          Computing cohomology. In Vasconcelos: Computational methods in
-         commutative algebra and algebraic geometry. Springer (1998)].
+         commutative algebra and algebraic geometry. Springer (1998)].@*
+         By default, the procedure uses @code{mres} to compute the Ext
+         modules. If called with the additional parameter @code{\"sres\"},
+         the @code{sres} command is used instead.
 SEE ALSO: dimH, sheafCohBGG
 EXAMPLE: example sheafCoh; shows an example
 "
 {
+  int use_sres;
   if( typeof(attrib(M,"isHomog"))!="intvec" ) {
      if (size(M)==0) { attrib(M,"isHomog",0); }
      else { ERROR("No admissible degree vector assigned"); }
+  }
+  if (size(#)>0) {
+    if (#[1]=="sres") { use_sres=1; }
   }
   int i,j;
@@ -420 +427 @@
   int col=h-l+1;
   intmat newBetti[n+1][col];
-  list L=Ext_R(v,M,1)[2];     // list of GB for Ext_R
+  if (use_sres) { list L=Ext_R(v,M,1,"sres")[2]; }
+  else          { list L=Ext_R(v,M,1)[2]; }
   for (i=l; i<=h; i++) {
     N0=L[n+2];    
@@ -565 +573 @@
  print(betti(FI),"betti");
  module F=FI[2];
- def A1=sheafCoh(F,-6,6);
- def A2=sheafCohBGG(F,-6,6);
+ int t=timer; 
+ def A1=sheafCoh(F,-8,8);
+ timer-t;
+ t=timer;
+ def A2=sheafCohBGG(F,-8,8);
+ timer-t;
 
  LIB "sheafcoh.lib";