scipy.fft.fhtoffset#

scipy.fft.fhtoffset(dln, mu, initial=0.0, bias=0.0)[source]#

Return optimal offset for a fast Hankel transform.

Returns an offset close to initial that fulfils the low-ringing condition of [1] for the fast Hankel transform fht with logarithmic spacing dln, order mu and bias bias.

Parameters:
dlnfloat

Uniform logarithmic spacing of the transform.

mufloat

Order of the Hankel transform, any positive or negative real number.

initialfloat, optional

Initial value for the offset. Returns the closest value that fulfils the low-ringing condition.

biasfloat, optional

Exponent of power law bias, any positive or negative real number.

Returns:
offsetfloat

Optimal offset of the uniform logarithmic spacing of the transform that fulfils a low-ringing condition.

See also

fht

Definition of the fast Hankel transform.

References

[1]

Hamilton A. J. S., 2000, MNRAS, 312, 257 (astro-ph/9905191)

Examples

>>> from scipy.fft import fhtoffset
>>> dln = 0.1
>>> mu = 2.0
>>> initial = 0.5
>>> bias = 0.0
>>> offset = fhtoffset(dln, mu, initial, bias)
>>> offset
0.5454581477676637