Re: Performance problem with Clone Method

This does the same thing as your Clone method but takes 1/3rd the time (for 10x10 matrices), just by not doing the completely redundant second map:

sub Clone2 {
    my $self = shift @_;
    my $matrix = $self->Matrix;
    return Matrix->new(
        "Matrix" => [ map{ [ @$_ ] } @$matrix ]
    );
}
[download]

If your matrices are very small (3x5 or 4x4 or less), then it might be worth breaking some OO taboos to gain a little more. This also does the same thing, but avoids a couple of method calls per invocation:

sub Clone3{
    my $self = shift;
    bless { "Matrix" => [ 
        map{ [ @$_ ] } @{ $self->{Matrix} } ] 
    }, 'Matrix';
}
[download]

But in the end, if a call that takes 3 milliseconds (your original for a 100x100 matrix) takes 80% of your time, then you should really start questioning why it is necessary to Clone something 35 million times? It seems to me that using a better algorithm is likely to produce far greater savings.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^2: Performance problem with Clone Method by Commandosupremo (Novice) on Jul 26, 2011 at 23:33 UTC
I have implemented what you called Clone2 in place of my original clone and it does make a substantial difference. The matrices I am working with are very large, on the order of hundreds by hundreds As for changing algorithms, I wish I could but it is not an option, no other algorithm provides as simple of an implementation nor the ability to modify it as this one does. Just FYI, the algorithm I am working with is the Ullmann algorithm for finding maximum subgraph isomorphism. Lastly, I should point out that I believe I might have been wrong about the number of times the clone method is being called. According to smallprof the original clone method is called 35Million times but I don't believe this is accurate. After replacing clone with clone 2, which should be called the same number of times smallprof says it is being called 1.06 Million times. I know this is ancillary but curious nonetheless. I don't know if this is an error/limitation with smallprof but its worth pointing out nonetheless.	[reply]
Re^3: Performance problem with Clone Method by BrowserUk (Patriarch) on Jul 26, 2011 at 23:51 UTC
I am working with is the Ullmann algorithm for finding maximum subgraph isomorphism I suspect that if you posted your implementation that its performance could be improved substantially. Especially if you are manipulating large 2D arrays of 0's & 1's much of the time. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]