# calculating intersection points in probability curves Classic List Threaded 3 messages Open this post in threaded view
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## calculating intersection points in probability curves

 Administrator Hello, I am performing a curve fit and also showing a distribution histogram envelope in my plot. In order to help the reader to evaluate the result I would like to draw certain boundaries (vertical and horizontal lines). While I am aware on how to draw such lines with matplotlib, I would like to know whether there are some functions in scipy or matplotlib which help me to retrieve the coordinates a) at which two curves intersect b) at which a distribution reaches a certain value? Example: How do I get the y-axis value which is reached by the green curve in http://matplotlib.sourceforge.net/_images/histogram_demo_extended_021.pngat a x-axis value of in 175? I could proably use a solver from numpy like http://docs.scipy.org/doc/numpy/reference/generated/numpy.linalg.solve.html#numpy.linalg.solvebut if I plot a distribution, the equation of the envelove is unknown at the first place. I'd appreciate your help or pointers to examples. Thanks a lot in advance, Timmie _______________________________________________ SciPy-User mailing list [hidden email] http://mail.scipy.org/mailman/listinfo/scipy-user