> >>> In a 1-d array, find the first point where all subsequent points >>> have values >>> less than a threshold. > > This doesn't imply monotonicity. > Suppose with have a sin curve, and I want to find the last trough. Or > a business cycle and I want to find the last recession. > > Unless my english deteriorated recently. >
Not sure that I follow? I read the statement as: find the smallest non-negative index i such that array[j] < t for all i <= j < len(array) for which the various solutions proposed work, except for the corner case where array.min() >= t. I'm not sure where monotonicity comes into play, unless one interprets the "all subsequent points" clause as "some number of subsequent points" or something... For those sort of problems, I usually wind up smoothing the array [optional], and then using scipy.ndimage.maximum to calculate peak values within a given window, and then find the points that equal the peak values -- this works pretty robustly for peak/trough detection in arbitrary dimension. _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
