[Python-Dev] [Python-checkins] r61796 - in python/trunk: Doc/library/random.rst Lib/random.py Lib/test/test_random.py Misc/NEWS

[Nick Coghlan]

> +## -------------------- triangular --------------------
> +
> +    def triangular(self, low, high, mode):
> +        """Triangular distribution.
> +
> +        Continuous distribution bounded by given lower and upper limits,
> +        and having a given mode value in-between.
> +
> +        http://en.wikipedia.org/wiki/Triangular_distribution
> +
> +        """
> +        u = self.random()
> +        c = (mode - low) / (high - low)
> +        if u > c:
> +            u = 1 - u
> +            c = 1 - c
> +            low, high = high, low
> +        return low + (high - low) * (u * c) ** 0.5
> +

Would it be worth having default values on the parameters for this?

     def triangular(self, low=0, high=1, mode=None):
         u = self.random()
         if mode is None:
             c = 0.5
         else:
             c = (mode - low) / (high - low)
         if u > c:
             u = 1 - u
             c = 1 - c
             low, high = high, low
         return low + (high - low) * (u * c) ** 0.5

At the very least, supporting mode=None would be convenient when you 
want a symmetric triangular distribution - having to calculate the 
median, pass it in as the mode, then have the function reverse that to 
get 0.5 seems a little wasteful.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
---------------------------------------------------------------
             http://www.boredomandlaziness.org