* Added rdiff() function to calculate element-wise relative difference of

two arrays.
master
Wirawan Purwanto 11 years ago
parent a0d8ed87a3
commit aaa06dc531
  1. 33
      math/stats/array_stats.py

@ -23,6 +23,14 @@ import numpy
CONVENTIONS CONVENTIONS
- Usually, M1 is the matrix under examination, M2 is the reference matrix. - Usually, M1 is the matrix under examination, M2 is the reference matrix.
PRINCIPLES
- Make sure functions are dimension-independent as much as possible
(i.e. not limited to 1D or 2D only).
- Text output should not hardwired only to sys.stdout via vanilla print
statement.
""" """
def report_diff_stat(M1, M2, out=sys.stdout): def report_diff_stat(M1, M2, out=sys.stdout):
@ -106,7 +114,7 @@ def maxadiff_by_col(M1, M2):
def maxradiff(M1, M2, ztol=1e-15): def maxradiff(M1, M2, ztol=1e-15):
# Original function name: maxrdiff # Original function name: maxrdiff
"""Prints the maximum *relative* absolute difference between two matrices. """Returns the maximum *relative* absolute difference between two matrices.
Used for checking whether two matrices are identical. Used for checking whether two matrices are identical.
CAVEATS: CAVEATS:
@ -121,6 +129,29 @@ def maxradiff(M1, M2, ztol=1e-15):
return (diff / mref0).max() return (diff / mref0).max()
def rdiff(M1, M2, ztol=1e-15, Abs=False):
"""Returns the *relative* [absolute] difference between two matrices.
Used for checking whether two matrices are identical.
Here, M1 is the array being compared, and M2 is the reference array.
CAVEATS:
- Zero elements in M2 (reference matrix) are converted to unity for
calculating the relative difference.
"""
from numpy import abs, array, asarray
(mapprox, mref) = (M1, M2)
if Abs:
diff = abs(asarray(mapprox) - asarray(mref))
mref0 = abs(asarray(mref))
numpy.putmask(mref0, mref0 < ztol, [1.0])
else:
diff = asarray(mapprox) - asarray(mref)
mref0 = array(mref, copy=True) # must make a copy
numpy.putmask(mref0, abs(mref0) < ztol, [1.0])
return (diff / mref0)
class ArrayStat(object): class ArrayStat(object):
"""A class to compute the statistics of an array. """A class to compute the statistics of an array.
""" """

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