Next: ignore, Previous: idlrestore, Up: Internal Routines [Contents][Index]

`igamma(`

`a`, `x` [, /complement, /log])

Returns the lower normalized incomplete gamma function: integral over
`t`

from 0 to

of
`x``exp(-t)*t^(`

, for `a`-1)/gamma(`a`)

positive
and `a`

nonnegative. If keyword `x``/complement`

is
specified, then one minus the integral is returned. If keyword
`/log`

is specified, then the natural logarithm of the result is
returned instead.