Code here. You'll need to change the path to boost headers in the includes to make it run. Part that runs way too slow: chrono.begin(); for(int i=0; i<nombremult; i++) res = prod(m,n); if(chrono.elapsed()<1000) fileoutput << chrono.elapsed() << " " << chrono.elapsed_micro() << " "; else fileoutput << chrono.elapsed() << " " << 0 << " "; } This goes far faster on visual than on xcode. Le 30 juin 2010 à 18:09, Christopher Jefferson a écrit :
On 30 Jun 2010, at 16:55, Raphaël Amiot wrote:
Hello there.
I am implementing matrix multiplication and am trying to have my stuff run as fast as possible. But then I noticed something strange. Using Xcode,
resultmatrix = prod(matrix1,matrix2);
is 10 to 16 times slower (with 100x100 matrixes) than simply doing something like that:
for(...) for(...) for(..) multiply_things();
And 20 to 40 times slower than a simple threaded approach.
Using visual studio, it's 2 times faster than naive multiplication.
This is on a release build, with #define BOOST_UBLAS_NDEBUG 1 #define NDEBUG 1
So what gives?_______________________________________________
Could you provide a small complete program which shows your problem?
Chris
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