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Function std.mathspecial.gammaIncomplete

Incomplete gamma integral and its complement

real gammaIncomplete (
  real a,
  real x
) pure nothrow @nogc @safe;

These functions are defined by

gammaIncomplete = ( 0x e-t ta-1 dt )/ Γ(a)

gammaIncompleteCompl(a,x) = 1 - gammaIncomplete(a,x) = (x e-t ta-1 dt )/ Γ(a)

In this implementation both arguments must be positive. The integral is evaluated by either a power series or continued fraction expansion, depending on the relative values of a and x.


Stephen L. Moshier (original C code). Conversion to D by Don Clugston


Boost License 1.0.