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From: Rob Speer <rspeer@MIT.EDU>  20100226 23:30:41

It's hard to tell from the Web, but it sounds like the right thing to do when I encounter unexpected behavior in PySparse is to email this list, right? I'm trying to assign to a slice of an ll_mat from another matrix. If this other matrix is also an ll_mat, this works fine. However, it acts very strange if the other matrix is a standard NumPy ndarray:  In [1]: from pysparse.spmatrix import * In [2]: sq = ll_mat(5,5) In [3]: sq Out[3]: <ll_mat object at 0x1d26bf0> In [4]: print sq > print(sq) ll_mat(general, [5,5]):                          In [6]: import numpy as np In [7]: sq[:,:] = np.arange(25).reshape((5,5)) In LHS=RHS, RHS has shape (2,27483600), LHS has shape (5,5)  ValueError Traceback (most recent call last) /Users/rspeer/python/src/pysparse/<ipython console> in <module>() ValueError: Matrix shapes are different  There seems to be no other straightforward way to convert a small dense matrix to a sparse one, either. Am I missing how to do this, or is this a bug that should be fixed?  Rob 
From: Dominique Orban <dominique.orban@gm...>  20100227 11:09:45

On Fri, Feb 26, 2010 at 11:30 PM, Rob Speer <rspeer@...> wrote: > It's hard to tell from the Web, but it sounds like the right thing to > do when I encounter unexpected behavior in PySparse is to email this > list, right? > > I'm trying to assign to a slice of an ll_mat from another matrix. If > this other matrix is also an ll_mat, this works fine. However, it acts > very strange if the other matrix is a standard NumPy ndarray: > >  > In [1]: from pysparse.spmatrix import * > > In [2]: sq = ll_mat(5,5) > > In [3]: sq > Out[3]: <ll_mat object at 0x1d26bf0> > > In [4]: print sq > > print(sq) > ll_mat(general, [5,5]): >      >      >      >      >      > > In [6]: import numpy as np > > In [7]: sq[:,:] = np.arange(25).reshape((5,5)) > In LHS=RHS, RHS has shape (2,27483600), LHS has shape (5,5) >  > ValueError Traceback (most recent call last) > > /Users/rspeer/python/src/pysparse/<ipython console> in <module>() > > ValueError: Matrix shapes are different >  > > There seems to be no other straightforward way to convert a small > dense matrix to a sparse one, either. Am I missing how to do this, or > is this a bug that should be fixed? Rob, Yes, emailing this list is the right thing to do. Welcome to Pysparse! Indeed, Pysparse expects the righthand side of an assignment to be a ll_mat object. Currently, you can't assign from a dense matrix or easily convert a dense matrix to a ll_mat object. I agree that this functionality would be useful. I might not have a chance to code that before a few weeks though. If anyone wants to have a stab at it, I can get them started.  Dominique 
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