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fix #488 : added rtol and atol arguments to LArray.equals #582

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Merged
merged 1 commit into from
Feb 16, 2018
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fix #488 : added rtol and atol arguments to LArray.equals #582

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24 changes: 23 additions & 1 deletion doc/source/changes/version_0_28.rst.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -231,7 +231,29 @@ Miscellaneous improvements

>>> arr = read_csv('arr.csv', nb_axes=3)

Closes :issue:`548`:
Closes :issue:`548`.

* added the relative tolerance `rtol` and the absolute tolerance `atol` arguments to the `LArray.equals` method.
These two arguments can be used to test the equality between two arrays within a given relative or
absolute tolerance:

>>> arr1 = LArray([6., 8.], "a=a0,a1")
>>> arr1
a a0 a1
6.0 8.0
>>> arr2 = LArray([5.999, 8.001], "a=a0,a1")
>>> arr2
a a0 a1
5.999 8.001
>>> arr1.equals(arr2)
False
>>> # equals returns True if abs(array1 - array2) <= (atol + rtol * abs(array2))
>>> arr1.equals(arr2, atol=0.01)
True
>>> arr1.equals(arr2, rtol=0.01)
True

Closes :issue:`488`.

* renamed argument `transpose` by `wide` in `to_csv` method.

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42 changes: 38 additions & 4 deletions larray/core/array.py
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Expand Up @@ -5225,14 +5225,18 @@ def __int__(self):
def __float__(self):
return self.data.__float__()

def equals(self, other, nan_equals=False):
def equals(self, other, rtol=0, atol=0, nan_equals=False):
"""
Compares self with another array and returns True if they have the same axes and elements, False otherwise.

Parameters
----------
other: LArray-like
Input array. aslarray() is used on a non-LArray input.
rtol : float or int, optional
The relative tolerance parameter (see Notes). Defaults to 0.
atol : float or int, optional
The absolute tolerance parameter (see Notes). Defaults to 0.
nan_equals: boolean, optional
Whether or not to consider nan values at the same positions in the two arrays as equal.
By default, an array containing nan values is never equal to another array, even if that other array
Expand All @@ -5244,6 +5248,15 @@ def equals(self, other, nan_equals=False):
bool
Returns True if self is equal to other.

Notes
-----
For finite values, equals uses the following equation to test whether two values are equal:

absolute(array1 - array2) <= (atol + rtol * absolute(array2))

The above equation is not symmetric in array1 and array2, so that equals(array1, array2) might be different
from equals(array2, array1) in some rare cases.

Examples
--------
>>> arr1 = ndtest((2, 3))
Expand All @@ -5261,6 +5274,24 @@ def equals(self, other, nan_equals=False):
>>> arr1.equals(arr3)
False

Test equality between two arrays within a given tolerance range.
Return True if absolute(array1 - array2) <= (atol + rtol * absolute(array2)).

>>> arr1 = LArray([6., 8.], "a=a0,a1")
>>> arr1
a a0 a1
6.0 8.0
>>> arr2 = LArray([5.999, 8.001], "a=a0,a1")
>>> arr2
a a0 a1
5.999 8.001
>>> arr1.equals(arr2)
False
>>> arr1.equals(arr2, atol=0.01)
True
>>> arr1.equals(arr2, rtol=0.01)
True

Arrays with nan values

>>> arr1 = ndtest((2, 3), dtype=float)
Expand All @@ -5283,10 +5314,13 @@ def equals(self, other, nan_equals=False):
other = aslarray(other)
except Exception:
return False
if nan_equals:
return self.axes == other.axes and all(nan_equal(self, other))
if rtol == 0 and atol == 0:
if nan_equals:
return self.axes == other.axes and all(nan_equal(self, other))
else:
return self.axes == other.axes and np.array_equal(np.asarray(self), np.asarray(other))
else:
return self.axes == other.axes and np.array_equal(np.asarray(self), np.asarray(other))
return self.axes == other.axes and np.allclose(np.asarray(self), np.asarray(other), rtol, atol, nan_equals)

def divnot0(self, other):
"""Divides array by other, but returns 0.0 where other is 0.
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