# scipy.special.erfcinv¶

scipy.special.erfcinv(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'erfcinv'>

Inverse of the complementary error function.

Computes the inverse of the complementary error function.

In the complex domain, there is no unique complex number w satisfying erfc(w)=z. This indicates a true inverse function would have multi-value. When the domain restricts to the real, 0 < x < 2, there is a unique real number satisfying erfc(erfcinv(x)) = erfcinv(erfc(x)).

It is related to inverse of the error function by erfcinv(1-x) = erfinv(x)

Parameters
yndarray

Argument at which to evaluate. Domain: [0, 2]

Returns
erfcinvndarray

The inverse of erfc of y, element-wise

`erf`

Error function of a complex argument

`erfc`

Complementary error function, `1 - erf(x)`

`erfinv`

Inverse of the error function

Examples

1. evaluating a float number

```>>> from scipy import special
>>> special.erfcinv(0.5)
0.4769362762044698
```
1. evaluating an ndarray

```>>> from scipy import special
>>> y = np.linspace(0.0, 2.0, num=11)
>>> special.erfcinv(y)
array([        inf,  0.9061938 ,  0.59511608,  0.37080716,  0.17914345,
-0.        , -0.17914345, -0.37080716, -0.59511608, -0.9061938 ,
-inf])
```