sage.topology: Modularization fixes for imports

Author: Matthias Koeppe

src/sage/topology/cubical_complex.py

@@ -75,11 +75,13 @@
 from sage.sets.set import Set
 from sage.rings.integer_ring import ZZ
 from sage.rings.rational_field import QQ
-from sage.matrix.constructor import matrix
 from sage.misc.cachefunc import cached_method
+from sage.misc.lazy_import import lazy_import
 from sage.misc.superseded import deprecation
 from functools import total_ordering
 
+lazy_import('sage.matrix.constructor', 'matrix')
+
 
 @total_ordering
 class Cube(SageObject):

src/sage/topology/delta_complex.py

@@ -54,10 +54,12 @@
 from sage.rings.integer_ring import ZZ
 from sage.rings.rational_field import QQ
 from sage.rings.integer import Integer
-from sage.matrix.constructor import matrix
 from .simplicial_complex import Simplex, lattice_paths, SimplicialComplex
 from sage.arith.misc import binomial
 from sage.misc.cachefunc import cached_method
+from sage.misc.lazy_import import lazy_import
+
+lazy_import('sage.matrix.constructor', 'matrix')
 
 
 class DeltaComplex(GenericCellComplex):

src/sage/topology/simplicial_complex.py

@@ -174,10 +174,11 @@
 from sage.structure.category_object import normalize_names
 from sage.misc.latex import latex
 from sage.misc.superseded import deprecation
-from sage.matrix.constructor import matrix
 from functools import total_ordering
 from itertools import combinations, chain
+
 lazy_import('sage.categories.simplicial_complexes', 'SimplicialComplexes')
+lazy_import('sage.matrix.constructor', 'matrix')
 
 
 def lattice_paths(t1, t2, length=None):

src/sage/topology/simplicial_complex_morphism.py

@@ -106,11 +106,13 @@
 from sage.categories.homset import Hom
 from sage.categories.morphism import Morphism
 from sage.categories.simplicial_complexes import SimplicialComplexes
-from sage.matrix.constructor import matrix, zero_matrix
+from sage.misc.lazy_import import lazy_import
 from sage.rings.integer_ring import ZZ
 
 from .simplicial_complex import Simplex, SimplicialComplex
 
+lazy_import('sage.matrix.constructor', ['matrix', 'zero_matrix'])
+
 
 def is_SimplicialComplexMorphism(x):
     """

src/sage/topology/simplicial_set.py

@@ -256,9 +256,9 @@
 
 import copy
 
-from sage.matrix.constructor import matrix
 from sage.misc.cachefunc import cached_method
 from sage.misc.fast_methods import WithEqualityById
+from sage.misc.lazy_import import lazy_import
 from sage.rings.integer import Integer
 from sage.rings.integer_ring import ZZ
 from sage.rings.rational_field import QQ
@@ -269,8 +269,8 @@
 from .delta_complex import DeltaComplex
 from .simplicial_complex import SimplicialComplex
 
-from sage.misc.lazy_import import lazy_import
 lazy_import('sage.categories.simplicial_sets', 'SimplicialSets')
+lazy_import('sage.matrix.constructor', 'matrix')
 
 
 ########################################################################

src/sage/topology/simplicial_set_morphism.py

@@ -36,12 +36,13 @@
 from sage.categories.homset import Hom, Homset
 from sage.categories.morphism import Morphism
 from sage.categories.simplicial_sets import SimplicialSets
-from sage.matrix.constructor import matrix, zero_matrix
 from sage.misc.latex import latex
 from sage.rings.integer_ring import ZZ
 
 from .simplicial_set import SimplicialSet_arbitrary
 
+lazy_import('sage.matrix.constructor', ['matrix', 'zero_matrix'])
+
 
 class SimplicialSetHomset(Homset):
     r"""