Remove a useless test in the breakpoint binary search + fix a bug (the index has to be initialized to iMin instead of 0: if iMin = iMax, we never enter the loop and we haven't set i properly …)
Do not decrement an size_t (aka unsigned long) unless you know that it is > 0
Commit a useless assert, especially when it comes to benchmarking (huge loss of time).
Improve the function that finds the crossing breakpoint. It now tries to limit the spread of the binary search when searching for the breakpoint for a given position. For the multi size benchmark for sizes up to 300x300 (by steps of 20 and 50 sample matrices), it improves the performances of the function by 25%