scipp.sinc

scipp.sinc(x, *, out=None)

Element-wise sine cardinal.

This function is defined as

\[\begin{split}\text{sinc}(x) = \begin{cases} 1&x = 0,\\ \frac{\sin(x)}{x}&x \neq 0 \end{cases}\end{split}\]

Note

NumPy uses a different definition for numpy.sinc(): \(\text{sinc}(x) = \sin(\pi x) / (\pi x)\) Scipp uses the definition that is more common in mathematics and physics while NumPy uses the definition from signal processing. To get the NumPy convention in Scipp, use sc.sinc(np.pi * x).

The input must have unit rad or be dimensionless. In either case, the output is dimensionless.

Parameters:

• x (scipp.typing.VariableLike) – Input data.

• out (Optional[TypeVar(VariableLikeType, Variable, DataArray, Dataset, DataGroup[Any])], default: None) – Optional output buffer.

Returns:

Same type as input – The sine cardinal values of the input.

Examples

Compute sinc:

>>> import scipp as sc
>>> import numpy as np
>>> x = sc.array(dims=['x'], values=[-1.0, 0.0, 1.0], unit='rad')
>>> sc.sinc(x)
<scipp.Variable> (x: 3)    float64  [dimensionless]  [0.841471, 1, 0.841471]