Mikkel Meyer Andersen a écrit :
> 2010/1/29 Luc Maisonobe <luc.maison...@free.fr>:
>> Bill Barker a écrit :
>>>
>>> --------------------------------------------------
>>> From: "Luc Maisonobe" <luc.maison...@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.maison...@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, <l...@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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>>
>
> Good point. I agree, too. If a user really wants to check if a zero
> exist, she must do it herself. But I think it's a point worth
> mentioning quite clearly in the docs.
If we keep the simple iterator and don't introduce sparse iterator yet,
there is no special handling for zeroes.
Luc
>
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