Re: Defect in XSH exp

["Clive D.W. Feather" <yyyyy@xxxxxxxxx>]

yyyyyyyy@xxxxxxx said:
> {
>   static double c = 0.39894228040143267794;  /* 1.0/sqrt(2*M_PI) */

Not a good idea, since this may or may not be the right sequence of digits
for any given implementation.

>   return c*exp(-x*x/2);
> }

If you can't just put:

    return exp(-x*x/2) / sqrt (2*M_PI);

then do something like:

    static double c = 0;

    if (c < 0.25)
        c = 1.0 / sqrt (2 * M_PI);

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