scipy.special.chdtri#

scipy.special.chdtri(v, p, out=None) = <ufunc 'chdtri'>#

Inverse to chdtrc with respect to x.

Returns x such that chdtrc(v, x) == p.

Parameters:
varray_like

Degrees of freedom.

parray_like

Probability.

outndarray, optional

Optional output array for the function results.

Returns:
xscalar or ndarray

Value so that the probability a Chi square random variable with v degrees of freedom is greater than x equals p.

See also

chdtrc, chdtr, chdtriv

Notes

Array API Standard Support

chdtri has support for Python Array API Standard compatible backends in addition to NumPy. The following combinations of backend and device (or other capability) are supported.

Library

CPU

GPU

NumPy

✅

n/a

CuPy

n/a

✅

PyTorch

✅

⛔

JAX

✅

⛔

Dask

✅

n/a

For the NumPy backend, this function supports all NumPy ufunc keyword arguments. Other backends may support out, but none of the other ufunc kwargs. out is typically supported for CuPy and PyTorch, but not currently in cases where SciPy relies on a generic Array API implementation or, for PyTorch on CPU, falls back to the NumPy backend. out is never supported for JAX because JAX arrays are immutable. chdtri does not currently support out for the PyTorch backend.

See Support for the array API standard for more information.

References

Examples

>>> import scipy.special as sc

It inverts chdtrc.

>>> v, p = 1, 0.3
>>> sc.chdtrc(v, sc.chdtri(v, p))
0.3
>>> x = 1
>>> sc.chdtri(v, sc.chdtrc(v, x))
1.0
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