Changeset 4cb6b8 in git

Timestamp:

Jan 7, 2001, 2:56:52 AM (23 years ago)

Author:

Gert-Martin Greuel <greuel@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

f74e95cfbb3d354be6beae9aa43c8da9c42ca6a6

Parents:

b5726ce4d97d33dace26cc34caed15f16bb4cb26

Message:

* GMG: Kosmetik; proc ringweights von general.lib eingefuegt


git-svn-id: file:///usr/local/Singular/svn/trunk@5017 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• Singular/LIB/ring.lib (modified) (3 diffs)

Singular/LIB/ring.lib

@@ -1 +1 @@
 //(GMG, last modified 03.11.95)
 ///////////////////////////////////////////////////////////////////////////////
-version="$Id: ring.lib,v 1.15 2000-12-31 01:57:42 greuel Exp $";
+version="$Id: ring.lib,v 1.16 2001-01-07 01:56:52 greuel Exp $";
 category="General purpose";
 info="
@@ -19 +19 @@
  ord_test(R);             test wether ordering of R is global, local or mixed
  ringtensor(\"R\",s,t,..);create ring R, tensor product of rings s,t,...
-           (parameters in square brackets [] are optional)
+ ringweights(r);          intvec of weights of ring variables of ring r
+             (parameters in square brackets [] are optional)
 ";
 
@@ -754 +755 @@
 }
 ///////////////////////////////////////////////////////////////////////////////
+
+proc ringweights (list # )
+"USAGE:   ringweights(P); P=name of an existing ring (true name, not a string)
+RETURN:  intvec consisting of the weights of the variables of P, as they 
+         appear when typing P;.
+NOTE:    This is useful when enlarging P but keeping the weights of the old
+         variables.
+EXAMPLE: example ringweights; shows an example
+"
+{
+   int ii,q,fi,fo,fia;
+   intvec rw,nw;
+   string os;
+   def P = #[1];
+   string osP = ordstr(P);
+   fo  = 1;
+//------------------------- find weights in ordstr(P) -------------------------
+   fi  = find(osP,"(",fo);
+   fia = find(osP,"a",fo)+find(osP,"w",fo)+find(osP,"W",fo);
+   while ( fia )
+   {
+      os = osP[fi+1,find(osP,")",fi)-fi-1];
+      if( find(os,",") )
+      {
+         execute("nw = "+os+";");
+         if( size(nw) > ii )
+         {
+             rw = rw,nw[ii+1..size(nw)];
+         }
+         else  {  ii = ii - size(nw); }
+
+         if( find(osP[1,fi],"a",fo) ) { ii = size(nw); }
+      }
+      else
+      {
+         execute("q = "+os+";");
+         if( q > ii )
+         {
+            nw = 0; nw[q-ii] = 0;
+            nw = nw + 1;          //creates an intvec 1,...,1 of length q-ii
+            rw = rw,nw;
+         }
+         else { ii = ii - q; }
+      }
+      fo  = fi+1;
+      fi  = find(osP,"(",fo);
+      fia = find(osP,"a",fo)+find(osP,"w",fo)+find(osP,"W",fo);
+   }
+//-------------- adjust weight vector to length = nvars(P)  -------------------
+   if( fo > 1 )
+   {                                            // case when weights were found
+      rw = rw[2..size(rw)];
+      if( size(rw) > nvars(P) )
+      {
+         rw = rw[1..nvars(P)];
+      }
+      if( size(rw) < nvars(P) )
+      {
+         nw=0; nw[nvars(P)-size(rw)]=0; nw=nw+1; rw=rw,nw;
+      }
+   }
+   else
+   {                                         // case when no weights were found
+      rw[nvars(P)]= 0; rw=rw+1;
+   }
+   return(rw);
+}
+example
+{"EXAMPLE:";  echo = 2;
+  ring r0 = 0,(x,y,z),dp;
+  ringweights(r0);
+  ring r1 = 0,x(1..5),(ds(3),wp(2,3));
+  ringweights(r1);"";
+  // an example for enlarging the ring, keeping the first weights:
+  intvec v = ringweights(r1),6,2,3,4,5;
+  ring R = 0,x(1..10),(a(v),dp);
+  ordstr(R);
+}
+///////////////////////////////////////////////////////////////////////////////