scipy.special.pdtri#
- scipy.special.pdtri(k, y, out=None) = <ufunc 'pdtri'>#
Inverse to
pdtr
vs mReturns the Poisson variable m such that the sum from 0 to k of the Poisson density is equal to the given probability y: calculated by
gammaincinv(k + 1, y)
. k must be a nonnegative integer and y between 0 and 1.- Parameters:
- karray_like
Number of occurrences (nonnegative, real)
- yarray_like
Probability
- outndarray, optional
Optional output array for the function results
- Returns:
- scalar or ndarray
Values of the shape parameter m such that
pdtr(k, m) = p
See also
Notes
Array API Standard Support
pdtri
has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variableSCIPY_ARRAY_API=1
and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.Library
CPU
GPU
NumPy
✅
n/a
CuPy
n/a
✅
PyTorch
✅
⛔
JAX
⚠️ no JIT
⛔
Dask
✅
n/a
See Support for the array API standard for more information.
Examples
>>> import scipy.special as sc
Compute the CDF for several values of m:
>>> m = [0.5, 1, 1.5] >>> p = sc.pdtr(1, m) >>> p array([0.90979599, 0.73575888, 0.5578254 ])
Compute the inverse. We recover the values of m, as expected:
>>> sc.pdtri(1, p) array([0.5, 1. , 1.5])