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https://issues.apache.org/jira/browse/MATH-1130?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Venkatesha Murthy TS updated MATH-1130:
---------------------------------------
Description:
These are utility functions mostly required as part of MathArrays.
MathArrays:
=============
The requirement is as follows:
a) double[] copyOf(double[] values, int begin, int length) ;
Similar to most other functions that support slice defined by the array part
from [begin, begin+length) ;its a requirement to copy a slice which is not
available (the closest is copyOf(array, int len) which misses out the begin
index)
b) double[] removeAll(double[] values, int begin, int length, double removable);
Need a function to remove a value from array slice defined by
[begin,begin+length) and return the filtered version.
c) double[] replaceAll(double[] values, int begin, int length, double oldValue,
double newValue);
Need a function to replace inplace an oldValue substituted with newValue in the
array slice defined by [begin,begin+length) and return the original complete
array with just replaced values only in the segment [begin,begin+length)
MathUtils
=========
boolean canEqual(double d1, double d2) ;
provide a canEqual function that is slightly better than exisitng
MathUtils.equals. We could also improve existing equals method however.
So the change here is that the new enhanced canEqual can do a quick check on
Nans and then move to a detailed Double.compare(..) method. This avoids the
Double.compare call when any one of them is NaN.
was:
These are utility functions mostly required as part of MathArrays.
MathArrays:
=============
The requirement is as follows:
a) double[] copyOf(double[] values, int begin, int length) ;
Similar to most other functions that support slice defined by the array part
from [begin, begin+length) ;its a requirement to copy a slice which is not
available (the closest is copyOf(array, int len) which misses out the begin
index)
b) double[] removeAll(double[] values, int begin, int length, double removable);
Need a function to remove a value from array slice defined by
[begin,begin+length) and return the filtered version.
c) double[] replaceAll(double[] values, int begin, int length, double oldValue,
double newValue);
Need a function to replace inplace an oldValue substituted with newValue in the
array slice defined by [begin,begin+length) and return the original complete
array with just replaced values only in the segment [begin,begin+length)
MathUtils
=========
boolean canEqual(double d1, double d2) ;
provide a canEqual function that is slightly better than exisitng
MathUtils.equals. We could also improve existing equals method however.
So the change here is that the new enhanced canEqual can do a quick check on
Nans and as well as both +ve and -ve Infinities faster and then move to a
detailed Double.compare(..) method. This avoids the Double.compare call for
infinities and NaN with faster reference equal check (i.e == ).
> A new set of functions for copyof, remove and replace a given value on a
> slice of array
> ---------------------------------------------------------------------------------------
>
> Key: MATH-1130
> URL: https://issues.apache.org/jira/browse/MATH-1130
> Project: Commons Math
> Issue Type: New Feature
> Affects Versions: 3.4
> Reporter: Venkatesha Murthy TS
> Attachments: math-1130-canequal.patch, math-1130-checknotnan.patch,
> math-1130-remove.patch, math-1130-replace.patch, math-1130.patch
>
>
> These are utility functions mostly required as part of MathArrays.
> MathArrays:
> =============
> The requirement is as follows:
> a) double[] copyOf(double[] values, int begin, int length) ;
> Similar to most other functions that support slice defined by the array
> part from [begin, begin+length) ;its a requirement to copy a slice which is
> not available (the closest is copyOf(array, int len) which misses out the
> begin index)
> b) double[] removeAll(double[] values, int begin, int length, double
> removable);
> Need a function to remove a value from array slice defined by
> [begin,begin+length) and return the filtered version.
> c) double[] replaceAll(double[] values, int begin, int length, double
> oldValue, double newValue);
> Need a function to replace inplace an oldValue substituted with newValue in
> the array slice defined by [begin,begin+length) and return the original
> complete array with just replaced values only in the segment
> [begin,begin+length)
> MathUtils
> =========
> boolean canEqual(double d1, double d2) ;
> provide a canEqual function that is slightly better than exisitng
> MathUtils.equals. We could also improve existing equals method however.
> So the change here is that the new enhanced canEqual can do a quick check on
> Nans and then move to a detailed Double.compare(..) method. This avoids the
> Double.compare call when any one of them is NaN.
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