Changeset c661e3 in git

Timestamp:

Oct 11, 2010, 4:43:19 PM (14 years ago)

Author:

Viktor Levandovskyy <levandov@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

d5abcfb5a8d5981beafb238eb7ab2390e274e781

Parents:

ebd7d86c7d81364a678cca227095db453f88aed6

Message:

*levandov: assume Qring build in, more description

git-svn-id: file:///usr/local/Singular/svn/trunk@13450 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• Singular/LIB/sagbi.lib (modified) (10 diffs)

Singular/LIB/sagbi.lib

@@ -17 +17 @@
 computations.
 
+Guide: new implementations of sagbi, sagbiPart, sagbiReduce, sagbiSPoly 
+as well as algebraicDependence by Jan Hackfeld do not support computations 
+over a quotient ring yet. On the contrary, sagbiReduction and sagbiNF do
+work over any ring.
+
 PROCEDURES:
  sagbiSPoly(A [,r,m]); computes SAGBI S-polynomials of A
@@ -55 +60 @@
   example sagbiPart;
   example algebraicDependence;
+}
+
+static proc assumeQring()
+{
+  if (ideal(basering) != 0)
+  {
+    ERROR("This function has not yet been implemented over qrings.");
+  }
 }
 
@@ -482 +495 @@
 EXAMPLE:  example sagbiSPoly; shows an example"
 {
+  assumeQring();
   int returnRing;
   int method=0;
@@ -568 +582 @@
 
 proc sagbiReduce(idealORpoly, ideal algebra, list #)
-"USAGE:   sagbiReduce(I, A[, tr, mt]); I, A ideals, tr, mt optional integers
-RETURN:   ideal of remainders of I after SAGBI reduction by A
+"USAGE: sagbiReduce(I, A[, tr, mt]); I, A ideals, tr, mt optional integers
+RETURN: ideal of remainders of I after SAGBI reduction by A
 ASSUME: basering is not a qring
 PURPOSE: 
@@ -583 +597 @@
 EXAMPLE:  example sagbiReduce; shows an example"
 {
+  assumeQring();
   int tailreduction=0; //Default
   int method=0; //Default
@@ -677 +692 @@
 EXAMPLE:  example sagbi; shows an example"
 {
+  assumeQring();
   int tailreduction=0; //default value
   int method=0; //default value
@@ -741 +757 @@
 EXAMPLE:  example sagbiPart; shows an example"
 {
+  assumeQring();
   int tailreduction=0; //default value
   int method=0; //default value
@@ -807 +824 @@
 EXAMPLE: example algebraicDependence; shows an example"
 {
+  assumeQring();
   def br=basering;
   int i;
@@ -1082 +1100 @@
 "USAGE: sagbiNF(id,dom,k[,n]); id either poly or ideal,dom ideal, k and n positive intergers.
 RETURN: same as type of id; ideal or polynomial.
-ASSUME: basering is not a qring
 PURPOSE:
 @format
@@ -1092 +1109 @@
     n may take the values (0 or default),1 or 2.
 @end format
+NOTE: sagbiNF works over both rings and quotient rings
 EXAMPLE: example sagbiNF; show example "
 {
-   return(sagbiReduce(id,dom,k));
+  ideal rs;
+  if (ideal(basering) == 0)
+  {
+    rs = sagbiReduce(id,dom,k) ;
+  }
+  else
+  {
+    rs = sagbiReduction(id,dom,k) ;
+  }
+  return(rs);
 }
 example
 {"EXAMPLE:"; echo = 2;
  ring r=0,(x,y),dp;
+ poly p=x4+x2y+y;
+ ideal dom =x2,x2y+y,x3y2;
+ sagbiNF(p,dom,1);
  ideal I= x2-xy;
- qring Q=std(I);
- ideal dom =x2,x2y+y,x3y2;
- poly p=x4+x2y+y;
- sagbiNF(p,dom,0);
+ qring Q=std(I); // we go to the quotient ring
+ poly p=imap(r,p);
+ NF(p,std(0)); // the representative of p has changed
+ ideal dom = imap(r,dom);
+ print(matrix(NF(dom,std(0)))); // dom has changed as well
+ sagbiNF(p,dom,0); // no tail reduction
  sagbiNF(p,dom,1);// tail subalgebra reduction is performed
 }