Changeset 5645:2537226feb05

Timestamp:

08/08/07 13:09:57 (6 years ago)

Author:

'Martin Albrecht <malb@…

Branch:

default

Message:

added libSINGULAR versions of std and slimgb Groebner basis computations
to get rid of conversion overhead for small GB calculations

Files:

• sage/libs/singular/singular-cdefs.pxi (modified) (3 diffs)
• sage/rings/polynomial/multi_polynomial_ideal.py (modified) (2 diffs)
• sage/rings/polynomial/multi_polynomial_ideal_libsingular.pyx (added)
• sage/rings/polynomial/multi_polynomial_libsingular.pxd (modified) (1 diff)
• setup.py (modified) (1 diff)

sage/libs/singular/singular-cdefs.pxi

@@ -40 +40 @@
 
     ctypedef struct napoly "polyrec"
+
+    cdef enum tHomog:
+        isNotHomog
+        isHomog
+        testHomog
 
     cdef enum rRingOrder_t:
@@ -117 +122 @@
     ctypedef struct omBin "omBin_s"
 
-    # numbers, i.e. coefficients
-    
-
 
     # SINGULAR Init
@@ -359 +361 @@
     void idShow(ideal *i)
     int IDELEMS(ideal *i)
+
+
+    void idSkipZeroes (ideal *ide)
+    long idRankFreeModule(ideal *m, ring *r)
+    ideal *kStd(ideal *i, ideal *q, tHomog h, intvec *w)
+    ideal *t_rep_gb(ring *r,ideal *arg_I, int syz_comp, int F4_mode)

sage/rings/polynomial/multi_polynomial_ideal.py

@@ -426 +426 @@
         return self.__groebner_basis
 
+    def _groebner_basis_using_libsingular(self, algorithm="std"):
+        """
+        Return a Groebner basis of this ideal. If a groebner basis for
+        this ideal has been calculated before the cached Groebner
+        basis is returned regardless of the requested algorithm.
+
+        ALGORITHM: Uses libSINGULAR.
+
+        INPUT:
+            algorithm -- 'std'      - Buchberger's algorithm
+                         'slimgb'   - SlimGB algorithm
+
+        EXAMPLES:
+
+        We compute a Groebner basis of 'cyclic 4' relative to
+        lexicographic ordering.
+        
+            sage: R.<a,b,c,d> = PolynomialRing(QQ, 4, order='lex')
+            sage: I = sage.rings.ideal.Cyclic(R,4); I
+            Ideal (a + b + c + d, a*b + a*d + b*c + c*d, a*b*c + a*b*d + a*c*d + b*c*d, a*b*c*d - 1) of Polynomial Ring in a, b, c, d over Rational Field
+            sage: I._groebner_basis_using_libsingular()
+            [c^2*d^6 - c^2*d^2 - d^4 + 1, c^3*d^2 + c^2*d^3 - c - d, b*d^4 - b + d^5 - d, b*c - b*d^5 + c^2*d^4 + c*d - d^6 - d^2, b^2 + 2*b*d + d^2, a + b + c + d]
+        """
+        from sage.rings.polynomial.multi_polynomial_ideal_libsingular import std_libsingular, slimgb_libsingular
+
+        try:
+            return self.__groebner_basis
+        except AttributeError:
+            if algorithm=="std":
+                S = std_libsingular(self)
+            elif algorithm=="slimgb":
+                S = slimgb_libsingular(self)
+            else:
+                raise TypeError, "algorithm '%s' unknown"%algorithm
+            self.__groebner_basis = S
+        return self.__groebner_basis
+
     def _singular_groebner_basis(self):
         try:
@@ -1040 +1077 @@
         elif algorithm.startswith('singular:'):
             return self._groebner_basis_using_singular(algorithm[9:])
+        elif algorithm.startswith('libsingular:'):
+            return self._groebner_basis_using_libsingular(algorithm[len('libsingular:'):])
         elif algorithm == 'macaulay2:gb':
             return self._macaulay2_groebner_basis()

sage/rings/polynomial/multi_polynomial_libsingular.pxd

@@ -21 +21 @@
     cdef ring *_ring
     cdef int _cmp_c_impl(left, Parent right) except -2
+

setup.py

@@ -425 +425 @@
     Extension('sage.rings.polynomial.multi_polynomial_libsingular',
               sources = ['sage/rings/polynomial/multi_polynomial_libsingular.pyx'],
+              libraries = ['gmp', 'm', 'readline', 'singular', 'singcf', 'singfac', 'omalloc', 'givaro', 'gmpxx'],
+              language="c++",
+              include_dirs=[SAGE_ROOT +'/local/include/singular']), \
+
+    Extension('sage.rings.polynomial.multi_polynomial_ideal_libsingular',
+              sources = ['sage/rings/polynomial/multi_polynomial_ideal_libsingular.pyx'],
               libraries = ['gmp', 'm', 'readline', 'singular', 'singcf', 'singfac', 'omalloc', 'givaro', 'gmpxx'],
               language="c++",