— Function: int gsl_histogram2d_find (const gsl_histogram2d * h, double x, double y, size_t * i, size_t * j)

This function finds and sets the indices i and j to the to the bin which covers the coordinates (x,y). The bin is located using a binary search. The search includes an optimization for histograms with uniform ranges, and will return the correct bin immediately in this case. If (x,y) is found then the function sets the indices (i,j) and returns GSL_SUCCESS. If (x,y) lies outside the valid range of the histogram then the function returns GSL_EDOM and the error handler is invoked.