On 7/27/11 7:30 AM, Gilles Sadowski wrote:
> Hello.
>
>>>> In project SIRIUS (CNES), we have some need for a Matrix33 (3 columns,
>>>> 3
>>>> rows) object. It is very common to use this kind of matrix to apply
>>>> rotation to a position vector (vector3D).
>>>>
>>>> The incompatibility between the Vector3D of geometry package and the
>>>> matrix/vectors of the linear package is a lack that we propose to fill
>>>> by creating a "Matrix33" in the geometry.threed package.
>>> Looks finie to me.
> Except for the name: "Matrix33" -> "Matrix3D".
>
>> [...]
>>
>>>> We will also propose some new constructors to build gaps between this
>>>> new matrix and the matrix of linear package.
>>> Yes, having a way to change from one view to the other is a clear need.
>> Yes, we prefer to add a constructor from Array2DRowRealMatrix and a getter
>> (that returns a Array2DRowRealMatrix) than to implement the whole interface
>> RealMatrix
> There are not that many methods. It's preferable to implement "RealMatrix"
> lest there will be two API eveolving independently.
+1
> I'm sure that somebody will help implement the missing bits if necessary.
>
>> (or inherit the AbstractMatrix).
> At the moment, I tend to agree on this point, given what I've just observed
> with this benchmark:
+1 - the difference is expected, since AbstractRealMatrix has to use
getters/setters and Array2DRowRealMatrix can do direct array
access. I guess to maximize reuse a) the array-based operations
could be extracted into a static utils class somewhere and used by
both impls or b) the new class could extend Array2DRowRealMatrix.
Phil
> ---CUT---
> public void testAddPerf() {
> final Array2DRowRealMatrix mAR = new Array2DRowRealMatrix(testData);
> final RealMatrix mR = mAR;
> final Array2DRowRealMatrix mInv = new
> Array2DRowRealMatrix(testDataInv);
>
> PerfTestUtils.timeAndReport("add",
> 200,
> 10000,
> new PerfTestUtils.RunTest("RealMatrix") {
> RealMatrix mPlusMInv;
> public void run() {
> mPlusMInv = mR.add(mInv);
> }},
> new
> PerfTestUtils.RunTest("Array2DRowRealMatrix") {
> RealMatrix mPlusMInv;
> public void run() {
> mPlusMInv = mAR.add(mInv);
> }});
> }
> ---CUT---
>
> The result is:
> ---CUT---
> add
> RealMatrix: 5.722274034999992E-4 ms
> Array2DRowRealMatrix: 4.3001998499999885E-4 ms
> ---CUT---
>
> Thus, in the first "RunTest", it is the (slower) "AbtractRealMatrix.add"
> method that is used, although "mR" is the same object as "mAR" (and an
> instance of "Array2DRowRealMatrix").
>
>> [...]
>
> Regards,
> Gilles
>
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