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 experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_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.

References

[1]

Chi-Square distribution, https://www.itl.nist.gov/div898/handbook/eda/section3/eda3666.htm

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