Changeset 78e2fd in git for factory/canonicalform.cc

Timestamp:

Jul 14, 1997, 2:45:07 PM (27 years ago)

Author:

Jens Schmidt <schmidt@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

e1a0bd7739355c4d2a5c76f07eae73d641b31c3c

Parents:

9ea9c61e58613776c6f87c9b161c4ba78f200283

Message:

	* canonicalform.cc (initCanonicalForm): initialization of
	  SW_USE_SPARSEMOD added

	* canonicalform.cc (CanonicalForm::degree( Variable )): doc fix

	* canonicalform.cc (CanonicalForm::degree): doc fix


git-svn-id: file:///usr/local/Singular/svn/trunk@511 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• factory/canonicalform.cc (modified) (5 diffs)

factory/canonicalform.cc

@@ -1 +1 @@
 /* emacs edit mode for this file is -*- C++ -*- */
-/* $Id: canonicalform.cc,v 1.8 1997-07-01 12:48:00 schmidt Exp $ */
+/* $Id: canonicalform.cc,v 1.9 1997-07-14 12:45:07 schmidt Exp $ */
 
 #include <config.h>
@@ -227 +227 @@
 }
 
+//{{{ int CanonicalForm::degree() const
+//{{{ docu
+//
+// degree() - return degree in main variable.
+//
+// Returns -1 for the zero polynomial.
+//
+//}}}
 int
 CanonicalForm::degree() const
@@ -237 +245 @@
         return value->degree();
 }
-
+//}}}
+
+//{{{ int CanonicalForm::degree( const Variable & v ) const
+//{{{ docu
+//
+// degree() - return degree in variable v.
+//
+// Returns -1 for the zero polynomial.
+//
+// Note: If v is less than the main variable of CO we have to swap
+// variables which may be quite expensive.  Calculating the degree in
+// respect to an algebraic variable may fail.
+//
+//}}}
 int
 CanonicalForm::degree( const Variable & v ) const
@@ -250 +271 @@
         return value->degree();
     else  if ( v > mvar() )
+        // relatively to v, f is in a coefficient ring
         return 0;
     else {
+        // v < mvar(), make v main variable
         CanonicalForm f = swapvar( *this, v, mvar() );
-        if ( f.mvar() == mvar() )
-            return f.value->degree();
-        else
+        if ( f.mvar() == mvar() )
+            return f.value->degree();
+        else
+            // in this case, we lost our main variable because
+            // v did not occur in CO
             return 0;
     }
 }
+//}}}
 
 int
@@ -1137 +1163 @@
         Off( SW_FAC_QUADRATICLIFT );
         Off( SW_USE_EZGCD );
+        Off( SW_USE_SPARSEMOD );
 
         (void)initializeCharacteristic();