hesseflux.division¶

division : Divide two arrays, return otherwise if division by 0.

This module was written by Matthias Cuntz while at Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany, and continued while at Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Nancy, France.

Written Jan 2012 by Matthias Cuntz (mc (at) macu (dot) de)
Added wrapper div, May 2012, Matthias Cuntz
Ported to Python 3, Feb 2013, Matthias Cuntz
Do not return masked array if no masked array given, Oct 2014, Matthias Cuntz
Added two-digit year, Nov 2018, Matthias Cuntz
Removed bug that non-masked array was returned if masked array given, Sep 2015, Matthias Cuntz
Using numpy docstring format, May 2020, Matthias Cuntz

The following functions are provided

`division`(a, b[, otherwise, prec])	Divide two arrays, return otherwise if division by 0.
`div`(args, *kwargs)	Wrapper function for `division()`.

division(a, b, otherwise=nan, prec=0.0)[source]¶

Divide two arrays, return otherwise if division by 0.

Parameters:

a (array_like) – enumerator
b (array_like) – denominator
otherwise (float) – value to return if b=0 (default: np.nan)
prec (float) – if |b|<|prec| then otherwise

Returns:

ratio – a/b if |b| > |prec|

otherwise if |b| <= |prec|

Output is numpy array. It is a masked array if at least one of a or b is a masked array.

Return type:

numpy array or masked array

Examples

>>> a = [1., 2., 3.]
>>> b = 2.
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b)))
0.5 1.0 1.5

>>> a = [1., 1., 1.]
>>> b = [2., 1., 0.]
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b)))
0.5 1.0 nan
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b, 0.)))
0.5 1.0 0.0
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b, otherwise=0.)))
0.5 1.0 0.0
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b, prec=1.)))
0.5 nan nan

>>> import numpy as np
>>> a = np.array([1., 1., 1.])
>>> b = [2., 1., 0.]
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b)))
0.5 1.0 nan

>>> b = np.array([2., 1., 0.])
>>> print('{:.1f} {:.1f} {:.1f}'.format(*division(a, b)))
0.5 1.0 nan

>>> mask = [0, 0, 1]
>>> b = np.ma.array([2., 1., 0.], mask=mask)
>>> ratio = division(a, b)
>>> print(ratio)
[0.5 1.0 --]

div(*args, **kwargs)[source]¶

Wrapper function for division().

Examples

>>> a = [1., 2., 3.]
>>> b = 2.
>>> print('{:.1f} {:.1f} {:.1f}'.format(*div(a, b)))
0.5 1.0 1.5

>>> a = [1., 1., 1.]
>>> b = [2., 1., 0.]
>>> print('{:.1f} {:.1f} {:.1f}'.format(*div(a, b)))
0.5 1.0 nan
>>> print('{:.1f} {:.1f} {:.1f}'.format(*div(a, b, 0.)))
0.5 1.0 0.0
>>> print('{:.1f} {:.1f} {:.1f}'.format(*div(a, b, otherwise=0.)))
0.5 1.0 0.0
>>> print('{:.1f} {:.1f} {:.1f}'.format(*div(a, b, prec=1.)))
0.5 nan nan