Interpolator

class photonforge.Interpolator(x, y, method='linear', coords='real_imag', extrapolation='extrapolate', parameter_names=None)

Interpolator object.

Parameters:

• x (Sequence[float] | Sequence[Sequence[float]]) – Independent variable (parameter) values.

• y (Sequence[float | complex] | Sequence[Sequence[float | complex]]) – Dependent variable values. Multiple variables sharing the same parameter values can be interpolated simultaneously by setting to a sequence of vectors.

• method (str) – Interpolation method. See table below for options.

• coords (Literal["mag_phase", "real_imag"]) – Coordinate system used for interpolation of complex values.

• extrapolation (Literal["extrapolate", "constant"]) – Extrapolation strategy for query points outside the sampled interval (1D only). "extrapolate" continues the interpolant; "constant" clamps query points to the sample boundaries.

• parameter_names (Sequence[str] | None) – Optional names for each parameter.

Interpolation method	Description
"linear"	Linear interpolation between neighboring points
"barycentric"	Barycentric Lagrange interpolation
"cubicspline"	Cubic spline interpolation
"pchip"	Piecewise cubic Hermite interpolating polynomial
"akima"	Akima interpolation
"makima"	Modified Akima interpolation

Examples

>>> interp = pf.Interpolator([0, 1, 2], [-1, 1, 1])
>>> interp([0, 1.5])
array([-1.,  1.])

>>> interp = pf.Interpolator([0, 1, 2], [[-1, 1, 1], [0, -1, -2]])
>>> interp([0.5, 1, 3])
array([[ 0. ,  1. ,  1. ],
       [-0.5, -1. , -3. ]])

>>> # 2D interpolation (2 parameters, 1 value, 3 sample points)
>>> interp = pf.Interpolator(
...     [[0, 0], [1, -1], [2, 0]],
...     [10, 20, 30],
...     parameter_names=("param1", "param2"),
... )
>>> interp([0.5, -0.5])
15.0
>>> interp([[0, 0], [1.5, 0]])
array([10., 25.])

Note

Single-dimensional interpolation (single parameter) perform phase unwrapping when interpolating complex values in magnitude and phase. That is not supported for multi-dimensional interpolation.

Methods

copy()

Create a copy of this layer specification.

Attributes

coords	Interpolation coordinate system for complex values (read-only).
extrapolation	Extrapolation strategy for out-of-range query points (read-only).
method	Interpolation method (read-only).
parameter_names	Names for each parameter in x.
properties	Object properties.
x	Independent variable values (read-only).
y	Dependent variable values (read-only).

coords

Interpolation coordinate system for complex values (read-only).

Type:

str

copy()

Create a copy of this layer specification.

Returns:

New copy.

Return type:

Interpolator

extrapolation

Extrapolation strategy for out-of-range query points (read-only).

Type:

str

method

Interpolation method (read-only).

Type:

str

parameter_names

Names for each parameter in x.

Type:

tuple[str, …] | None

properties

Object properties.

Type:

Properties

x

Independent variable values (read-only).

Type:

ndarray

y

Dependent variable values (read-only).

Type:

ndarray | list[ndarray]