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From Luc Maisonobe <Luc.Maison...@free.fr>
Subject Re: svn commit: r904231 - in /commons/proper/math/trunk/src:main/java/org/apache/commons/math/linear/AbstractRealVector.javasite/xdoc/changes.xml test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
Date Fri, 29 Jan 2010 10:19:04 GMT
Bill Barker a écrit :
> 
> 
> --------------------------------------------------
> From: "Luc Maisonobe" <Luc.Maisonobe@free.fr>
> Sent: Friday, January 29, 2010 12:49 AM
> To: "Commons Developers List" <dev@commons.apache.org>
> Subject: Re: svn commit: r904231 - in
> /commons/proper/math/trunk/src:main/java/org/apache/commons/math/linear/AbstractRealVector.javasite/xdoc/changes.xml
> test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
> 
>> Bill Barker a écrit :
>>>
>>>
>>> --------------------------------------------------
>>> From: "Luc Maisonobe" <Luc.Maisonobe@free.fr>
>>> Sent: Thursday, January 28, 2010 12:14 PM
>>> To: "Commons Developers List" <dev@commons.apache.org>
>>> Subject: Re: svn commit: r904231 - in
>>> /commons/proper/math/trunk/src:main/java/org/apache/commons/math/linear/AbstractRealVector.javasite/xdoc/changes.xml
>>>
>>> test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
>>>
>>>> Mikkel Meyer Andersen a écrit :
>>>>> Hi.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Why use an iterator instead of just a simple for-loop? And what about
>>>>> saving
>>>>> the values until the vector invalidates - I see pros and cons for both
>>>>> approaches, so it's more to hear what your thoughts were?
>>>>
>>>> It is because there already are several implementations of the class
>>>> and
>>>> they may use different strategies to access elements. Such iterators
>>>> have been introduced by recent changes so I thought it was better to
>>>> stick with them now.
>>>>
>>>
>>> +1
>>> There is a case for using the sparseIterator, but that probably makes
>>> the methods overly complicated (since zero values have to be handled
>>> specially).
>>
>> I did hesitate to add this. I thought adding special getSparseMinIndex
>> and so on, that would explicitely ignore non-zeros. We can add them too
>> if you think ignoring zeros is the right thing to do. In that case, we
>> simply copy the methods and change iterator into sparse iterator, that's
>> all.
>>
> 
> I personally have no interest in getSparseMinIndex.  Granted, the
> iterator for OpenMapRealVector is slightly expensive (does a map lookup
> for each index), but the more I think about it the less I like using
> sparseIterator here.  This would involve something like:
>   if(minValue > 0) {
>     //repeat loop with iterator to find a zero value
>   }
> possibly traversing the vector twice.
> 
> For 2.1 I'd just go with this addition, and deal with any user
> complaints in a later version.

I agree.

Luc

> 
>> Luc
>>
>>>
>>>> As for saving the values, we cannot be sure when the vector changes.
>>>> Users may do this several ways and we simply did not implement any
>>>> control on that.
>>>>
>>>> Luc
>>>>
>>>>>
>>>>> Cheers, Mikkel.
>>>>>
>>>>> On 28/01/2010 8:42 PM, <luc@apache.org> wrote:
>>>>>
>>>>> Author: luc
>>>>> Date: Thu Jan 28 19:42:31 2010
>>>>> New Revision: 904231
>>>>>
>>>>> URL: http://svn.apache.org/viewvc?rev=904231&view=rev
>>>>> Log:
>>>>> added min/max getters for real vectors
>>>>> For compatibility reasons, these methods have been put in the topmost
>>>>> abstract class but not in the interface yet. It could be pushed to the
>>>>> interface when next major version will be released.
>>>>> JIRA: MATH-334
>>>>>
>>>>> Modified:
>>>>>
>>>>>
>>>>> commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
>>>>>
>>>>>
>>>>>    commons/proper/math/trunk/src/site/xdoc/changes.xml
>>>>>
>>>>>
>>>>> commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
>>>>>
>>>>>
>>>>>
>>>>> Modified:
>>>>> commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
>>>>>
>>>>>
>>>>> URL:
>>>>> http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java?rev=904231&r1=904230&r2=904231&view=diff
>>>>>
>>>>>
>>>>> ==============================================================================
>>>>>
>>>>>
>>>>> ---
>>>>> commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
>>>>>
>>>>>
>>>>> (original)
>>>>> +++
>>>>> commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
>>>>>
>>>>>
>>>>> Thu Jan 28 19:42:31 2010
>>>>> @@ -292,6 +292,58 @@
>>>>>         return d;
>>>>>     }
>>>>>
>>>>> +    /** Get the index of the minimum entry.
>>>>> +     * @return index of the minimum entry or -1 if vector length is
0
>>>>> +     * or all entries are NaN
>>>>> +     */
>>>>> +    public int getMinIndex() {
>>>>> +        int minIndex    = -1;
>>>>> +        double minValue = Double.POSITIVE_INFINITY;
>>>>> +        Iterator<Entry> iterator = iterator();
>>>>> +        while (iterator.hasNext()) {
>>>>> +            final Entry entry = iterator.next();
>>>>> +            if (entry.getValue() <= minValue) {
>>>>> +                minIndex = entry.getIndex();
>>>>> +                minValue = entry.getValue();
>>>>> +            }
>>>>> +        }
>>>>> +        return minIndex;
>>>>> +    }
>>>>> +
>>>>> +    /** Get the value of the minimum entry.
>>>>> +     * @return value of the minimum entry or NaN if all entries
>>>>> are NaN
>>>>> +     */
>>>>> +    public double getMinValue() {
>>>>> +        final int minIndex = getMinIndex();
>>>>> +        return minIndex < 0 ? Double.NaN : getEntry(minIndex);
>>>>> +    }
>>>>> +
>>>>> +    /** Get the index of the maximum entry.
>>>>> +     * @return index of the maximum entry or -1 if vector length is
0
>>>>> +     * or all entries are NaN
>>>>> +     */
>>>>> +    public int getMaxIndex() {
>>>>> +        int maxIndex    = -1;
>>>>> +        double maxValue = Double.NEGATIVE_INFINITY;
>>>>> +        Iterator<Entry> iterator = iterator();
>>>>> +        while (iterator.hasNext()) {
>>>>> +            final Entry entry = iterator.next();
>>>>> +            if (entry.getValue() >= maxValue) {
>>>>> +                maxIndex = entry.getIndex();
>>>>> +                maxValue = entry.getValue();
>>>>> +            }
>>>>> +        }
>>>>> +        return maxIndex;
>>>>> +    }
>>>>> +
>>>>> +    /** Get the value of the maximum entry.
>>>>> +     * @return value of the maximum entry or NaN if all entries
>>>>> are NaN
>>>>> +     */
>>>>> +    public double getMaxValue() {
>>>>> +        final int maxIndex = getMaxIndex();
>>>>> +        return maxIndex < 0 ? Double.NaN : getEntry(maxIndex);
>>>>> +    }
>>>>> +
>>>>>     /** {@inheritDoc} */
>>>>>     public RealVector mapAbs() {
>>>>>         return copy().mapAbsToSelf();
>>>>>
>>>>> Modified: commons/proper/math/trunk/src/site/xdoc/changes.xml
>>>>> URL:
>>>>> http://svn.apache.org/viewvc/commons/proper/math/trunk/src/site/xdoc/changes.xml?rev=904231&r1=904230&r2=904231&view=diff
>>>>>
>>>>>
>>>>> ==============================================================================
>>>>>
>>>>>
>>>>> --- commons/proper/math/trunk/src/site/xdoc/changes.xml (original)
>>>>> +++ commons/proper/math/trunk/src/site/xdoc/changes.xml Thu Jan 28
>>>>> 19:42:31
>>>>> 2010
>>>>> @@ -39,6 +39,10 @@
>>>>>   </properties>
>>>>>   <body>
>>>>>     <release version="2.1" date="TBD" description="TBD">
>>>>> +      <action dev="luc" type="add" issue="MATH-334" >
>>>>> +        Added min/max getters for real vectors (not yet in the
>>>>> RealVector
>>>>> interface for
>>>>> +        compatibility purposes, but in the AbstractRealVector
>>>>> abstract
>>>>> class).
>>>>> +      </action>
>>>>>       <action dev="luc" type="fix" issue="MATH-338" due-to="Vincent
>>>>> Morand">
>>>>>         Fixed automatic step initialization in embedded Runge-Kutta
>>>>> integrators.
>>>>>         The relative tolerance setting was never used, only the
>>>>> absolute
>>>>> tolerance
>>>>>
>>>>> Modified:
>>>>> commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
>>>>>
>>>>>
>>>>> URL:
>>>>> http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java?rev=904231&r1=904230&r2=904231&view=diff
>>>>>
>>>>>
>>>>> ==============================================================================
>>>>>
>>>>>
>>>>> ---
>>>>> commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
>>>>>
>>>>>
>>>>> (original)
>>>>> +++
>>>>> commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
>>>>>
>>>>>
>>>>> Thu Jan 28 19:42:31 2010
>>>>> @@ -1308,6 +1308,30 @@
>>>>>     }
>>>>>
>>>>>
>>>>> +    public void testMinMax()  {
>>>>> +        ArrayRealVector v1 = new ArrayRealVector(new double[] { 0,
>>>>> -6, 4,
>>>>> 12, 7 });
>>>>> +        assertEquals(1,  v1.getMinIndex());
>>>>> +        assertEquals(-6, v1.getMinValue(), 1.0e-12);
>>>>> +        assertEquals(3,  v1.getMaxIndex());
>>>>> +        assertEquals(12, v1.getMaxValue(), 1.0e-12);
>>>>> +        ArrayRealVector v2 = new ArrayRealVector(new double[] {
>>>>> Double.NaN,
>>>>> 3, Double.NaN, -2 });
>>>>> +        assertEquals(3,  v2.getMinIndex());
>>>>> +        assertEquals(-2, v2.getMinValue(), 1.0e-12);
>>>>> +        assertEquals(1,  v2.getMaxIndex());
>>>>> +        assertEquals(3, v2.getMaxValue(), 1.0e-12);
>>>>> +        ArrayRealVector v3 = new ArrayRealVector(new double[] {
>>>>> Double.NaN,
>>>>> Double.NaN });
>>>>> +        assertEquals(-1,  v3.getMinIndex());
>>>>> +        assertTrue(Double.isNaN(v3.getMinValue()));
>>>>> +        assertEquals(-1,  v3.getMaxIndex());
>>>>> +        assertTrue(Double.isNaN(v3.getMaxValue()));
>>>>> +        ArrayRealVector v4 = new ArrayRealVector(new double[0]);
>>>>> +        assertEquals(-1,  v4.getMinIndex());
>>>>> +        assertTrue(Double.isNaN(v4.getMinValue()));
>>>>> +        assertEquals(-1,  v4.getMaxIndex());
>>>>> +        assertTrue(Double.isNaN(v4.getMaxValue()));
>>>>> +    }
>>>>> +
>>>>> +
>>>>>     /** verifies that two vectors are close (sup norm) */
>>>>>     protected void assertClose(String msg, double[] m, double[] n,
>>>>>             double tolerance) {
>>>>>
>>>>
>>>>
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