scipy.special.ncfdtridfd#
- scipy.special.ncfdtridfd(dfn, p, nc, f, out=None) = <ufunc 'ncfdtridfd'>#
- Calculate degrees of freedom (denominator) for the noncentral F-distribution. - This is the inverse with respect to dfd of - ncfdtr. See- ncfdtrfor more details.- Parameters:
- dfnarray_like
- Degrees of freedom of the numerator sum of squares. Range (0, inf). 
- parray_like
- Value of the cumulative distribution function. Must be in the range [0, 1]. 
- ncarray_like
- Noncentrality parameter. Should be in range (0, 1e4). 
- farray_like
- Quantiles, i.e., the upper limit of integration. 
- outndarray, optional
- Optional output array for the function results 
 
- Returns:
- dfdscalar or ndarray
- Degrees of freedom of the denominator sum of squares. 
 
 - See also - Notes - The value of the cumulative noncentral F distribution is not necessarily monotone in either degrees of freedom. There thus may be two values that provide a given CDF value. This routine assumes monotonicity and will find an arbitrary one of the two values. - Examples - >>> from scipy.special import ncfdtr, ncfdtridfd - Compute the CDF for several values of dfd: - >>> dfd = [1, 2, 3] >>> p = ncfdtr(2, dfd, 0.25, 15) >>> p array([ 0.8097138 , 0.93020416, 0.96787852]) - Compute the inverse. We recover the values of dfd, as expected: - >>> ncfdtridfd(2, p, 0.25, 15) array([ 1., 2., 3.])