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(..)

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?