division

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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.

copyright:

Copyright 2012-2022 Matthias Cuntz, see AUTHORS.rst for details.

license:

MIT License, see LICENSE for details.

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().
History

  • 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

  • Output type is input type, Oct 2021, Matthias Cuntz

  • More consistent docstrings, Jan 2022, Matthias Cuntz

  • Use helper functions input2array and array2input, Mar 2022, Matthias Cuntz

  • Do not use geterr/seterr, Mar 2022, Matthias Cuntz

div(*args, **kwargs)[source]#

Wrapper function for division().

Examples

>>> a = [1., 2., 3.]
>>> b = 2.
>>> print(div(a, b))
[0.5, 1.0, 1.5]

>>> a = [1., 1., 1.]
>>> b = [2., 1., 0.]
>>> print(div(a, b))
[0.5, 1.0, nan]
>>> print(div(a, b, 0.))
[0.5, 1.0,  0.0]
>>> print(div(a, b, otherwise=0.))
[0.5, 1.0, 0.0]
>>> print(div(a, b, prec=1.))
[0.5, nan, nan]
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|

Return type:

numpy array or masked array

Notes

Output is numpy array. It is a masked array if at least one of a or b is a 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(division(a, b))
[0.5, 1.0, nan]
>>> print(division(a, b, 0.))
[0.5, 1.0, 0.0]
>>> print(division(a, b, otherwise=0.))
[0.5, 1.0, 0.0]
>>> print(division(a, b, prec=1.))
[0.5, nan, nan]

>>> import numpy as np
>>> a = np.array([1., 1., 1.])
>>> b = [2., 1., 0.]
>>> print(division(a, b))
[0.5 1.  nan]
>>> b = np.array([2., 1., 0.])
>>> print(division(a, b))
[0.5 1.  nan]

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