Coverage for local/lib/python2.7/site-packages/sage/matrix/change_ring.pyx : 100%

""" 

Functions for changing the base ring of matrices quickly. 

""" 

from __future__ import absolute_import 

from .matrix_space import MatrixSpace 

from .matrix_real_double_dense cimport Matrix_real_double_dense 

from .matrix_integer_dense cimport Matrix_integer_dense 

from sage.rings.real_double import RDF 

def integer_to_real_double_dense(Matrix_integer_dense A): 

""" 

Fast conversion of a matrix over the integers to a matrix with 

real double entries. 

INPUT: 

A -- a dense matrix over the integers 

OUTPUT: 

-- a dense real double matrix 

EXAMPLES: 

sage: a = matrix(ZZ,2,3,[-2,-5,3,4,8,1030339830489349908]) 

sage: a.change_ring(RDF) 

[ -2.0 -5.0 3.0] 

[ 4.0 8.0 1.0303398304893499e+18] 

sage: import sage.matrix.change_ring 

sage: sage.matrix.change_ring.integer_to_real_double_dense(a) 

[ -2.0 -5.0 3.0] 

[ 4.0 8.0 1.0303398304893499e+18] 

""" 

cdef Py_ssize_t i, j 

cdef Matrix_real_double_dense M 

S = MatrixSpace(RDF, A._nrows, A._ncols, sparse=False) 

M = Matrix_real_double_dense.__new__(Matrix_real_double_dense, 

S, None, None, None) 

for i from 0 <= i < A._nrows: 

for j from 0 <= j < A._ncols: 

M.set_unsafe_double(i,j,A.get_unsafe_double(i,j)) 

return M