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RE: Using LU in .NET and ActiveX

Trifon — Fri, 07 Sep 2007 06:31:17 GMT

There is not a method that directly supports this in MaXC but you may write your own code. The way to do this is described here:

http://en.wikipedia.org/wiki/LU_decomposition#Applications

It is true that our another product .NET Matrix Library supports this directly with its LU.Solve method.

RE: Using LU in .NET and ActiveX

cpede — Fri, 07 Sep 2007 05:35:14 GMT

That I understand, but how do I do the Solve method in the .NET LU is not covered.

Having the matrix to LU I can use:

mtx->LU(&l,&u,perIndex,&perSign);

but then I need to do the Solve against another matrix, using the l and u results from the decomposition? How do I do that?

-cpede

RE: Using LU in .NET and ActiveX

Trifon — Tue, 04 Sep 2007 05:10:28 GMT

First of all there are two distinct products you may use.

".NET Matrix Library" (NML) is intended to be used with .NET languages such as VB.NET C# and managed C++ .

"Matrix ActiveX Component" (MaXC) is targeted to VB6 but it can be used by all languages supporting COM such as native C++.

I assume you want to use MaXC with C++. If yes it may help you the C++ project that is found in under the "Samples" directory.

I have modify the example in order to perform LU decomposition and here is the code:

[code]
#include "stdafx.h"
#include "iostream.h"
#import "bluebitmatrix31.dll" no_namespace

HRESULT MatrixLU()
{
IMatrix *A;

long N = 6;

HRESULT hr;
hr = ::CoCreateInstance(__uuidof(Matrix), NULL, CLSCTX_INPROC, __uuidof(IMatrix), (void**)&A);
if(FAILED(hr))
return hr;

A->Size(N, N);
A->FillRandom(0, 10, 0);

cout << "===============================" << endl;
cout << "Matrix A =" << endl;
cout << A->GetString(3, _bstr_t("")) << endl;
cout << "===============================" << endl;

//Declare 2 matrix variables that will hold
//the L and U parts of LU decomposition
IMatrix *L, *U;
hr = ::CoCreateInstance(__uuidof(Matrix), NULL, CLSCTX_INPROC, __uuidof(IMatrix), (void**)&L);
if(FAILED(hr))
return hr;
hr = ::CoCreateInstance(__uuidof(Matrix), NULL, CLSCTX_INPROC, __uuidof(IMatrix), (void**)&U);
if(FAILED(hr))
return hr;

VARIANT * perIndex ;
perIndex = NULL;
long perSign = 0;

A->LU( &L, &U, perIndex, &perSign );

cout << endl;
cout << "===============================" << endl;
cout << "Matrix L =" << endl;
cout << L->GetString(3, _bstr_t("")) << endl;
cout << "===============================" << endl;

cout << endl;
cout << "===============================" << endl;
cout << "Matrix U =" << endl;
cout << U->GetString(3, _bstr_t("")) << endl;
cout << "===============================" << endl;

if(A)
A->Release();
if(L)
L->Release();
if(U)
U->Release();

return hr;
}

int main(int argc, char* argv[])
{
::CoInitialize(NULL);
MatrixLU();
//cout << "Please press return to exit";
//cin.get();
CoUninitialize(); // clearup
return 0;
}
[/code]

RE: Using LU in .NET and ActiveX

cpede — Mon, 03 Sep 2007 09:52:38 GMT

It's not entirely clear how I should convert the Basic code to C++. For example, in C# we can call the solve function to return the result from an LU decomp. In C++ it works another way. Can you give me a little code clip that complements in C#:

LU lu = new LU(mtx_l)
Matrix res_u = lu.Solve(mtx_u);

-cpede

RE: Using LU in .NET and ActiveX

Trifon — Tue, 28 Aug 2007 03:38:37 GMT

The ActiveX component uses a different interface and there is no LU object. You may use the LU method of the Matrix object. Please refer to the VB example given in the documentation:

http://www.bluebit.gr/matrix/version_31/LU.htm

It should not be difficult to convert the above code in C++.

Using LU in .NET and ActiveX

cpede — Tue, 28 Aug 2007 02:49:41 GMT

To start with, I'm totally new to this.

One of my colleagues made code in .NET using the LU class.

[code]LU lu = new LU(mtx_l);
if (lu.IsSingular) return false;
Matrix res_u = lu.Solve(mtx_u);[/code]

I'm now trying to convert this to C++ using the ActiveX version. I don't see the LU class, but only ad a method to Matrix.

Can anyone help me with an example on how to use the LU method in ActiveX?

-cpede