Re: [ublas] efficient way to convert a matrix to col major order

Subject: Re: [ublas] efficient way to convert a matrix to col major order
From: Umut Tabak (u.tabak_at_[hidden])
Date: 2011-08-08 07:26:42

> Hi Umut,
>
> I'm using the copy-constructor to change the order of the matrix, but I run into a memory problem, because I use very large matrices with around 10^6 - 10^9 (in some cases 10^12) non-zero elements, so with the copy constructor I duplicate the matrix data. I need only an iterator or something else for a column-major access without duplicating
>
> Phil
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>    
So you initialize the matrix A_csc which is column-major with a 
row-major matrix B_csr, is that the case? So the copy ctor is called,  
if this is the case, I tested this and this takes too much time on a 
matrix on the order of 100K. I am confused a bit... Can you confirm this?

-- 
If I have a thousand ideas and only one turns out to be good,
I am satisfied.
Alfred Nobel