| Re: [eigen] Block CG(p=1) vs CG Classic |
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On 23.07.2013 00:13, Pedro Torres wrote:
For example as you can see in the snapshop, block version took 4.8s and
classic version 3.8s, for a sparse matrix with n=14200. The number of
iterations for both was 2400.
It might be that you have an aliasing problem.
If you have expressions like P=A*Z; or P+=A*Z can you try
P.noAlias()=A*Z; (or +=)?
In general, I would like to set p at runtime.
I assume, that in practice the case p==1 will be very uncommon? If so it
would not make much sense to test that at runtime (although that would
be a very cheap test).
Could you recommend some tips or reference where I can read about this
optimization Sparse*MatrixXd(n,p) on Eigen's side?.
What I meant was that Eigen's Sparse*Dense product implementation may
have room for optimization. I did not look closely into that, though --
so don't take my word for granted here. Maybe Gael can give you some
pointers, if you really want to optimize that.
Christoph
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