mpylab.tools.interpol module

This is mpylab.tools.interpol.

Provides interpolation routines

author:

Hans Georg Krauthäuser (main author)

license:

GPL-3 or higher

exception mpylab.tools.interpol.DeprecatedDBFactorWarning

Bases: FutureWarning

An obsolete interpolation factor was explicitly supplied.

mpylab.tools.interpol.InterpolateMResults(y, x, interpolation=None)

Create interpolation function with optional log-axis transforms.

mpylab.tools.interpol.MResult_Interpol(dct, interpolation)

Create interpolation function from mapping of x->y values.

class mpylab.tools.interpol.UQ_interpol(dct, typ=None, frequency_scale='LINEAR', value_scale='LINEAR', complex_mode='POLAR', db_factor=None)

Bases: object

Interpolate uncertain quantities in their canonical linear unit.

Parameters:

  • dct (mapping) – Frequency-to-SCUQ-Quantity mapping.

  • typ (object, optional) – Unused historical argument retained for compatibility.

  • frequency_scale (str, optional) – LINEAR or LOG frequency coordinates.

  • value_scale (str, optional) – LINEAR or DB (geometric) value/magnitude interpolation. Real-valued DB interpolation also interpolates positive lower and upper bounds geometrically. This is not a unit conversion.

  • complex_mode (str, optional) – POLAR or CARTESIAN. DB requires POLAR. Complex covariance matrices retain their existing linear interpolation on the frequency axis.

  • db_factor (float or None, optional) – Deprecated, numerically ignored compatibility argument. Explicit 10 or 20 emits DeprecatedDBFactorWarning; other values are rejected. Omit this argument in new code, including for linear input units.

Raises:

  • ValueError – If a mode, legacy factor or logarithmic interpolation domain is invalid.

  • TypeError – If scalar and complex covariance uncertainty models are mixed.

Notes

The legacy db_factor attribute remains available as the supplied validated value, or None when omitted. It does not control the result. No removal release is scheduled; removing this compatibility argument requires a separately announced breaking change.

class mpylab.tools.interpol.cartesian_interpol(dct, frequency_scale='LINEAR')

Bases: object

Interpolate complex values through real and imaginary components.

class mpylab.tools.interpol.cplx_interpol(dct, typ=None, frequency_scale='LINEAR', magnitude_scale='LINEAR', db_factor=None)

Bases: object

Interpolate complex magnitudes and unwrapped phases independently.

Parameters:

  • dct (mapping) – Frequency-to-complex-value mapping.

  • typ (object, optional) – Unused historical argument retained for compatibility.

  • frequency_scale (str, optional) – LINEAR or LOG frequency coordinates.

  • magnitude_scale (str, optional) – LINEAR or DB (geometric) magnitude interpolation. DB requires nonzero magnitudes and needs no power/amplitude conversion factor.

  • db_factor (float or None, optional) – Deprecated, numerically ignored compatibility argument. Explicit 10 or 20 emits DeprecatedDBFactorWarning; other values are rejected. None is the default and produces no warning.

Raises:

ValueError – If a mode, legacy factor or logarithmic interpolation domain is invalid.

mpylab.tools.interpol.extrap1d(interpolator)

Return a vectorized interpolation function with linear extrapolation.

mpylab.tools.interpol.unwrap(dct, arg=None)

Phase unwrapping of values in dictionary dct.

dct is a dict with keys that can be sorted (frequencies). The values are typically complex values representing e.g. S-parameters.

If arg is given, it is expected to be a callable with a signature like math.atan2() that returns the argument (phase) of the objects in dct.

The function returns a 3-tuple of lists with the sorted keys, the magnitude, and the phase of the values.