#7199: inefficiency of creation of sparse matrices
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Reporter: zimmerma | Owner: was
Type: enhancement | Status: new
Priority: major | Milestone: sage-4.1.3
Component: linear algebra | Keywords:
Work_issues: | Author:
Reviewer: | Merged:
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The following was reported to me by David Monniaux.
{{{
sparseflag=True
def essai1():
m=identity_matrix(QQ,dimen,sparse=sparseflag)
compound=m
for i in xrange(count):
compound = compound.stack(m)
def essai2():
m_rows=identity_matrix(QQ,dimen,sparse=sparseflag).rows()
compound_l=[]
for i in xrange(count):
compound_l += m_rows
m=Matrix(QQ,compound_l,sparse=sparseflag)
def essai3():
m=identity_matrix(QQ,dimen,sparse=sparseflag)
compound=Matrix(QQ,m.nrows()*count,m.ncols(),sparse=sparseflag)
for i in xrange(count):
compound[m.nrows()*i:m.nrows()*(i+1),:] = m
}}}
I get with Sage 4.1.1 on a 2.83Ghz Core 2:
{{{
sage: count=200
sage: dimen=30
sage: timeit('essai1()',number=1)
1 loops, best of 3: 33.1 s per loop
sage: timeit('essai2()',number=1)
1 loops, best of 3: 25.4 s per loop
sage: timeit('essai3()')
5 loops, best of 3: 820 ms per loop
}}}
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7199>
Sage <http://www.sagemath.org>
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