Clean up cimports

Author: Matthias Koeppe

src/sage/algebras/quatalg/quaternion_algebra_element.pyx

@@ -34,7 +34,6 @@ Check that :trac:`20829` is fixed::
 
 from sage.structure.element cimport AlgebraElement, Element
 from sage.structure.richcmp cimport rich_to_bool, rich_to_bool_sgn, richcmp_item
-from sage.algebras.quatalg.quaternion_algebra_element cimport QuaternionAlgebraElement_abstract
 from sage.rings.rational cimport Rational
 from sage.rings.integer cimport Integer
 from sage.rings.number_field.number_field_element cimport NumberFieldElement

src/sage/libs/flint/fmpz_poly.pyx

@@ -27,7 +27,7 @@ from sage.arith.long cimport pyobject_to_long
 from sage.cpython.string cimport char_to_str, str_to_bytes
 from sage.structure.sage_object cimport SageObject
 from sage.rings.integer cimport Integer
-from sage.libs.flint.fmpz_poly cimport *
+
 
 cdef class Fmpz_poly(SageObject):
 

src/sage/matrix/matrix_modn_sparse.pyx

@@ -90,18 +90,26 @@ from sage.ext.stdsage cimport PY_NEW
 
 from sage.libs.flint.fmpz cimport fmpz_get_mpz, fmpz_set_mpz
 from sage.libs.flint.fmpz_mat cimport fmpz_mat_entry
+from sage.libs.gmp.mpz cimport mpz_set
 
 from sage.modules.vector_modn_sparse cimport *
 
 cimport sage.libs.linbox.givaro as givaro
 cimport sage.libs.linbox.linbox as linbox
 
-from sage.libs.linbox.conversion cimport *
-
-from .matrix2 cimport Matrix
-cimport sage.matrix.matrix as matrix
-cimport sage.matrix.matrix_sparse as matrix_sparse
-cimport sage.matrix.matrix_dense as matrix_dense
+from sage.libs.linbox.conversion cimport (get_method,
+                                          METHOD_DEFAULT,
+                                          METHOD_DENSE_ELIMINATION,
+                                          METHOD_SPARSE_ELIMINATION,
+                                          METHOD_BLACKBOX,
+                                          METHOD_WIEDEMANN,
+                                          new_linbox_matrix_modn_sparse,
+                                          new_linbox_matrix_integer_sparse,
+                                          new_linbox_vector_integer_dense,
+                                          new_sage_vector_integer_dense)
+
+from sage.matrix.matrix_sparse cimport Matrix_sparse
+from sage.matrix.matrix_dense cimport Matrix_dense
 from sage.rings.finite_rings.integer_mod cimport IntegerMod_int, IntegerMod_abstract
 from sage.rings.integer cimport Integer
 from sage.rings.rational_field import QQ
@@ -113,14 +121,14 @@ from sage.matrix.matrix2 import Matrix as Matrix2
 from .args cimport SparseEntry, MatrixArgs_init
 from sage.arith.misc import is_prime
 
-cimport sage.structure.element
-
 from sage.data_structures.binary_search cimport *
 from sage.modules.vector_integer_sparse cimport *
 
 from .matrix_integer_dense cimport Matrix_integer_dense
 from sage.modules.vector_integer_dense cimport Vector_integer_dense
 
+from sage.structure.element cimport Matrix
+
 ################
 # TODO: change this to use extern cdef's methods.
 from sage.rings.fast_arith cimport arith_int
@@ -133,7 +141,7 @@ ai = arith_int()
 # Github Issue #12679.
 MAX_MODULUS = 46341
 
-cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
+cdef class Matrix_modn_sparse(Matrix_sparse):
     def __cinit__(self):
         nr = self._nrows
         nc = self._ncols
@@ -257,7 +265,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
         else:
             raise ValueError("unknown matrix format")
 
-    cdef sage.structure.element.Matrix _matrix_times_matrix_(self, sage.structure.element.Matrix _right):
+    cdef Matrix _matrix_times_matrix_(self, Matrix _right):
         """
         This code is implicitly called for multiplying self by another
         sparse matrix.
@@ -336,7 +344,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
                 set_entry(&ans.rows[i], j, s)
         return ans
 
-    def _matrix_times_matrix_dense(self, sage.structure.element.Matrix _right):
+    def _matrix_times_matrix_dense(self, Matrix _right):
         """
         Multiply self by the sparse matrix _right, and return the
         result as a dense matrix.
@@ -361,7 +369,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
             <class 'sage.matrix.matrix_mod2_dense.Matrix_mod2_dense'>
         """
         cdef Matrix_modn_sparse right
-        cdef matrix_dense.Matrix_dense ans
+        cdef Matrix_dense ans
         right = _right
 
         cdef c_vector_modint* v
@@ -871,7 +879,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
             self.cache('det', d)
             return d
         elif algorithm == 'generic':
-            d = matrix_sparse.Matrix_sparse.determinant(self)
+            d = Matrix_sparse.determinant(self)
             self.cache('det', d)
             return d
         else:
@@ -949,7 +957,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
         if algorithm == "generic":
             return Matrix_sparse.solve_right(self, B)
         else:
-            if isinstance(B, sage.structure.element.Matrix):
+            if isinstance(B, Matrix):
                 from sage.matrix.special import diagonal_matrix
                 m, d = self._solve_matrix_linbox(B, algorithm)
                 return m  * diagonal_matrix([QQ((1,x)) for x in d])
@@ -1121,7 +1129,7 @@ cdef class Matrix_modn_sparse(matrix_sparse.Matrix_sparse):
         from sage.modules.free_module_element import vector
 
         cdef Matrix_integer_dense B
-        if not isinstance(mat, Matrix):
+        if not isinstance(mat, Matrix2):
             B = <Matrix_integer_dense?> matrix(ZZ, mat, sparse=False)
         else:
             B = <Matrix_integer_dense?> mat.change_ring(ZZ).dense_matrix()

src/sage/modules/vector_modn_sparse.pyx

@@ -7,8 +7,6 @@
 
 from cysignals.memory cimport sig_malloc, sig_free
 
-from sage.modules.vector_modn_sparse cimport c_vector_modint
-
 
 cdef int allocate_c_vector_modint(c_vector_modint* v, Py_ssize_t num_nonzero) except -1:
     """

src/sage/rings/complex_mpc.pyx

@@ -2557,4 +2557,3 @@ cdef class CCtoMPC(Map):
 
 # Support Python's numbers abstract base class
 # import numbers
-from sage.rings.complex_mpc import MPComplexNumber

src/sage/rings/ring_extension.pxd

@@ -1,6 +1,5 @@
 from sage.categories.map cimport Map
 from sage.rings.ring cimport CommutativeRing, CommutativeAlgebra
-from sage.rings.ring_extension cimport RingExtension_generic
 
 
 cdef class RingExtension_generic(CommutativeAlgebra):

src/sage/symbolic/constants_c_impl.pxi

@@ -16,9 +16,6 @@ The constant `e`
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
 
-from sage.symbolic.expression cimport Expression
-
-
 # keep exp(1) for fast access
 # this is initialized in the constructor of the class E below to prevent
 # circular imports while loading the library