`numpy.polynomial.chebyshev:_zseries_der`

source: /numpy/polynomial/chebyshev.py :275

Signature

def _zseries_der ( zs )

Summary

Differentiate a z-series.

Extended Summary

The derivative is with respect to x, not z. This is achieved using the chain rule and the value of dx/dz given in the module notes.

Parameters

zs : z-series: The z-series to differentiate.

Returns

derivative : z-series: The derivative

Notes

The zseries for x (ns) has been multiplied by two in order to avoid using floats that are incompatible with Decimal and likely other specialized scalar types. This scaling has been compensated by multiplying the value of zs by two also so that the two cancels in the division.

Aliases

numpy.polynomial.chebyshev._zseries_der