Changeset 738208 in git

Timestamp:

Dec 20, 2013, 2:07:40 PM (10 years ago)

Author:

Jakob Kröker <kroeker@…>

Branches:

(u'spielwiese', 'd1b01e9d51ade4b46b745d3bada5c5f3696be3a8')

Children:

3e032aa23883008eaeb717bed37aa560c44de867e33e5f31dc44bc1a57ac4a6531b88cfaa8486004

Parents:

4e4e24bd5220c690dc16529b1fb431b5ef67482c

git-author:

Jakob Kröker <kroeker@math.uni-hannover.de>2013-12-20 14:07:40+01:00

git-committer:

Jakob Kroeker <kroeker@uni-math.gwdg.de>2014-01-28 02:12:51+01:00

Message:

fix slocus bug 526(trac)

Files:

• Singular/LIB/ring.lib (modified) (1 diff)
• Singular/LIB/sing.lib (modified) (2 diffs)
• Tst/Short.lst (modified) (2 diffs)
• Tst/Short/bug_526.res.gz.uu (added)
• Tst/Short/bug_526.stat (added)
• Tst/Short/bug_526.tst (added)
• Tst/Short/ringutils_s.res.gz.uu (added)
• Tst/Short/ringutils_s.stat (added)
• Tst/Short/ringutils_s.tst (added)

Singular/LIB/ring.lib

@@ -849 +849 @@
   r;
 }
+
+
+
+
+proc isQuotientRing( rng )
+"USAGE: isQuotientRing ( rng );
+RETURN:  1 if rng is a quotient ring, 0 otherwise.
+PURPOSE: check if typeof a rng "qring"
+KEYWORDS: qring ring ideal 'factor ring'
+EXAMPLE: example isQuotientRing ; shows an example
+"
+{
+    return ( size(ideal(rng)) != 0 );
+}
+example
+{
+  ring rng = 0,x,dp;
+  isQuotientRing(rng); //no
+  // if a certain method does not support quotient rings, 
+  // then a parameter test could be performed:
+   ASSUME( 0, 0==isQuotientRing(basering));
+
+  qring q= ideal(x);  // constructs rng/ideal(x) 
+  isQuotientRing(q);  // yes
+}
+
+static proc testIsQuotientRing()
+{
+   ring rng = real,x,dp;
+   ASSUME(0, 0== isQuotientRing(rng) ) ;
+
+   qring qrng = 1;
+   ASSUME(0, isQuotientRing(qrng) ) ;
+
+   ring rng2 = integer,x,dp;
+   ASSUME(0, 0 == isQuotientRing(rng2) ) ;
+
+   qring qrng2=0;
+   ASSUME(0, isQuotientRing(qrng2) ) ;
+
+   ring rng3 = 0,x,dp;
+   ASSUME(0, 0 == isQuotientRing(rng3) ) ;
+
+   qring qrng3=1;
+   ASSUME(0, isQuotientRing(qrng3) ) ;
+}
+
+
+
+
+
+proc hasIntegerCoefficientRing( rng )
+"USAGE: hasIntegerCoefficientRing ( rng );
+RETURN:  1 if rng is has integer ring coefficients, 0 otherwise.
+KEYWORDS: integer ring coefficients 
+EXAMPLE: example hasIntegerCoefficientRing ; shows an example
+"
+proc hasIntegerCoefficientRing(rng)
+{
+  def rl = ringlist(rng);
+  if ( not (typeof(rl[1][1])=="string")    ) { return (0); }
+  return ( rl[1][1]=="integer" );
+}
+example
+{
+  ring rng = integer,x,dp;
+  hasIntegerCoefficientRing(rng); //yes
+  // if a certain method supports only rings with integer coefficients, 
+  // then a parameter test could be performed:
+   ASSUME( 0, hasIntegerCoefficientRing(basering)); //ok
+
+  ring rng2 = 0, x, dp; 
+  hasIntegerCoefficientRing(rng2);  // no
+}
+
+
+static proc testHasIntegerCoefficientRing()
+{
+   ring rng = integer,x,dp;
+   ASSUME(0, hasIntegerCoefficientRing( rng ) );
+
+   qring q = ideal(x);
+   ASSUME(0, hasIntegerCoefficientRing( q ) );
+
+   ring rng2 = 0,x,dp;
+   ASSUME(0, 0==hasIntegerCoefficientRing( rng2 ) );
+
+   ring rng3 = (0,a),x,dp;
+   ASSUME(0, 0==hasIntegerCoefficientRing( rng3 ) );
+
+   ring rng4 = (real,a),x,dp;
+   ASSUME(0, 0==hasIntegerCoefficientRing( rng4 ) );
+
+   ring rng5 = (real),x,dp;
+   ASSUME(0, 0==hasIntegerCoefficientRing( rng5 ) );
+}
+
+
+
+

Singular/LIB/sing.lib

@@ -362 +362 @@
 ///////////////////////////////////////////////////////////////////////////////
 
-proc slocus (ideal i)
+proc slocus(ideal i)
 "USAGE:   slocus(i);  i ideal
-RETURN:  ideal of singular locus of i
+RETURN:  ideal of singular locus of i. Quotient rings and rings with integer coefficients are currently not supported.
 EXAMPLE: example slocus; shows an example
 "
 {
+  // quotient rings currently not supported
+  ASSUME( 0, 0==isQuotientRing(basering) ); 
+  // integer coefficient rings currently not supported
+  ASSUME( 0, 0==hasIntegerCoefficientRing(basering) ); 
+
+
   def R=basering;
   int j,k;
@@ -415 +421 @@
 {
   ideal ist=std(i);
-  if(deg(ist[1])==0){return(ist);}
-  int cod  = nvars(basering)-dim(ist);
-  i        = i+minor(jacob(i),cod);
+  if ( size(ist)==0 ) // we have a zero ideal
+  { 
+     // the zero locus of the zero ideal is nonsingular
+     return( ideal(1) ) ;
+  }
+  if( deg( ist[1] ) == 0 ) // the ideal has a constant generator
+  {
+    return(ist);
+  }
+  int cod  = nvars(basering) - dim(ist);
+  i        = i + minor( jacob(i), cod );
   return(i);
 }

Tst/Short.lst

@@ -51 +51 @@
 Short/bug_51.tst
 Short/bug_52.tst
+Short/bug_526.tst
 Short/bug_53.tst
 Short/bug_54.tst
@@ -229 +230 @@
 Short/ringmodn.tst
 Short/ringsum.tst
+Short/ringutils_s.tst
 Short/ringz.tst
 Short/rInit.tst