change test on cf.type in interred

Author: frederichan-IMJPRG

src/sage/rings/polynomial/multi_polynomial_ideal.py

@@ -3530,8 +3530,7 @@ def groebner_basis(self, algorithm='', deg_bound=None, mult_bound=None, prot=Fal
             sage: gb  # optional - giacpy_sage
             [c^3 - 79/210*c^2 + 1/30*b + 1/70*c, b^2 - 3/5*c^2 - 1/5*b + 1/5*c, b*c + 6/5*c^2 - 1/10*b - 2/5*c, a + 2*b + 2*c - 1]
 
-            sage: ideal(gb).change_ring(P).interreduced_basis()  # optional - giacpy_sage
-            [a - 60*c^3 + 158/7*c^2 + 8/7*c - 1, b + 30*c^3 - 79/7*c^2 + 3/7*c, c^4 - 10/21*c^3 + 1/84*c^2 + 1/84*c]
+            sage: J.groebner_basis.set_cache(gb)  # optional - giacpy_sage
             sage: ideal(J.transformed_basis()).change_ring(P).interreduced_basis()  # testing trac 21884
             [a - 60*c^3 + 158/7*c^2 + 8/7*c - 1, b + 30*c^3 - 79/7*c^2 + 3/7*c, c^4 - 10/21*c^3 + 1/84*c^2 + 1/84*c]
 

src/sage/rings/polynomial/multi_polynomial_ideal_libsingular.pyx

@@ -280,7 +280,7 @@ def interred_libsingular(I):
         sage: P.<x,y,z> = PolynomialRing(QQ)
         sage: I = ideal( x^2 - 3*y, y^3 - x*y, z^3 - x, x^4 - y*z + 1 )
         sage: I.interreduced_basis()
-        [y*z^2 - 81*x*y - 9*y - z, z^3 - x, x^2 - 3*y, 9*y^2 - y*z + 1]
+        [y*z^2 - 81*x*y - 9*y - z, z^3 - x, x^2 - 3*y, y^2 - 1/9*y*z + 1/9]
     """
     global singular_options
 
@@ -310,7 +310,7 @@ def interred_libsingular(I):
 
 
     # divide head by coefficients
-    if r.cf.type == n_unknown:
+    if r.cf.type != n_Z and r.cf.type != n_Znm and r.cf.type != n_Zn and r.cf.type != n_Z2m :
         for j from 0 <= j < IDELEMS(result):
             p = result.m[j]
             if p: