Okay, so i've got a c++ program that does what I need, problem is, it's a little slow. Can anyone give me any pointers as to which operations cost a lot of time and which can be done rather fast ? I have to use a lot of loops (since i'm doing matrix algebra/operations and c++ doesn't allow me to extract a column from a matrix or anything like that without making a nice little loop, or declaring all the elements myself, afaik). I removed all my vector/matrix resizing, but apparently that isn't making much of a difference (well, might be a few seconds...)

So does anyone have any suggestions ?