cas/xcas implementation of Geometric PDF

[Wes Loewer]

(05-10-2021 06:23 PM)parisse Wrote:  There is no check on k being an integer for geometric_cdf since it's not necessary to compute the expression.

I take it that for the binomial and poisson cdf functions that this check is necessary, although I suppose at least the pdf versions could be calculated for non-integers using gamma functions for the factorials. Do your cdf implementations of binomial and poisson use a discrete summation, or something more sophisticated?

Still, it seems like for consistency and to avoid user error, it would be better to restrict the values to integers. Same for the return value of GEOMETRIC_ICDF(). Are there ever any situations where a non-integer is useful here?


In any case, the new Probability Wizard is treating the Geometric distribution as if it were continuous which produces some incorrect results. I'll file a report on that.