[Daniel_Khazaei]

Hello foamers


I am trying to define a Matrix in my OpenFOAM solver but I have a few problems.
I try to describe my problem with an example:

Assuming I want to define a Matrix in the solver, this is what I do:

Matrix<scalar> A(n, m, 0.0);

Now when I want to compile the solver, it gives me the following error:

setInterfaceDisplacement.H:98: error: wrong number of template arguments (1, should be 2)
/opt/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/Matrix.H:54: error: provided for ‘template<class Form, class Type> class Foam::Matrix’

I can understand that I need to add one more argument in declaration, but I don't know what does "class Form" mean?


regards

[kmou]

Hi,

I am encountering the same problem and would be grateful if you could share how you resolved this problem. Thank you very much.

[wyldckat]

Greetings to all!

Actually, while I was tracking kmou's posts, this previous thread gave the hint: http://www.cfd-online.com/Forums/ope...t-compile.html
The solution seems to be to use "scalarSquareMatrix" instead of "Matrix<scalar>".

A bit more explanation:

1. The definition of "scalarSquareMatrix" is made in the file "src/OpenFOAM/matrices/scalarMatrices/scalarSquareMatrix.H", where it defines the class based on the "SquareMatrix" template:
   

   class scalarSquareMatrix
   :
       public SquareMatrix<scalar>

2. The template class "SquareMatrix" is defined in the file "src/OpenFOAM/matrices/SquareMatrix/SquareMatrix.H", as follows:
   

   template<class Type>
   class SquareMatrix
   :
       public Matrix<SquareMatrix<Type>, Type>

   Namely, said "class Form" is "SquareMatrix<Type>" in this case... pretty confusing template voodoo, isn't it?

Either way, the quick solution is indicated in the post #3 at the aforementioned thread .

Best regards,
Bruno

[Daniel_Khazaei]

thanks for the suggestion...

I had resolved that issue a few weeks ago. I have changed the declaration as follow:

Matrix <scalarField,scalar> A (n,m)

---------


squareScalarMatrix is working fine on square matrices but how can I define a matrix with one column or one row?

like this one:

Matrix <scalarField,scalar> A (n,1) or A (1,n)

-------

OK I have fixed the last one by using rectangular matrix

[Daniel_Khazaei]

Originally Posted by kmou

Hi,

I am encountering the same problem and would be grateful if you could share how you resolved this problem. Thank you very much.

you need to add the following headers to your program:

#include "scalarSquareMatrix.H" --->> for square type matrix

if you want to define a square matrix: A (n,n) and initiate it with 0

scalarSquareMatrix A(n, 0.0);


#include "RectangularMatrix.H" ---->> for rectangular matrix

if you want to define a rectangular matrix: A (n,m)

RectangularMatrix <scalar> A(n,m);

[kmou]

Thank you Daniel and Bruno for your replies.
So new classes of matrices have been created, such as SquareMatrix and RectangularMatrix, which effectively correspond do the "Form" that is required. Thus, for each Matrix<scalar> that I have, I will need to make a decision as to if it is a Square matrix, or a Rectangular matrix or Diagonal matrix etc...

[13msmemusman]

Hi guys i have a problem related to matrices. I have to define and write a matrix in which every element have different dimensions. for example 1st element has dimensions in kilogram 2nd in meters 3rd in second like that. Please guide me how can i do that.

[wyldckat]

Originally Posted by 13msmemusman

Hi guys i have a problem related to matrices. I have to define and write a matrix in which every element have different dimensions. for example 1st element has dimensions in kilogram 2nd in meters 3rd in second like that. Please guide me how can i do that.

Quick answer: AFAIK, that's not possible. You should not include the dimensions in the matrix and instead you should only use the values.

[13msmemusman]

Thank you. but there should be a way...... coz..........

[wyldckat]

Originally Posted by 13msmemusman

Thank you. but there should be a way...... coz..........

If you had provided an example I could have worked with, it would have be easier/faster for me to figure it out.

Anyway, this is an example of how to do it:

    SquareMatrix<dimensionedScalar> hmm(3);

    hmm[0][0].dimensions().reset(dimLength);
    hmm[0][0] = dimensionedScalar("cookie1",dimLength,-3.0);
    hmm[0][1] = 10.0;
    hmm[0][2] = -4.0;
    hmm[1][0] = 2.0;
    hmm[1][1] = 3.0;
    hmm[1][2] = 10.0;
    hmm[2][0] = 2.0;
    hmm[2][1] = 6.0;
    hmm[2][2] = 1.0;

It's based on the test application "applications/test/Matrix" and it took me a while to figure out the details.

[13msmemusman]

Screenshot from 2016-03-23 23:45:51.png

Please have a look on this file attached.

[wyldckat]

Originally Posted by 13msmemusman

Please have a look on this file attached.

Quick questions:

1. What is the calculation you're trying to perform?
   • I ask this because this matrix has to be multiplied by something!?
2. How exactly is this matrix meant to be used?

[13msmemusman]

its matrix for mass in mass damper spring system. actually i am working with some kind of fluid and vehicle dynamics interface. Yes this matrix is gonna be multiplied by a vector

[wyldckat]

Hi Muhammad,

Originally Posted by 13msmemusman

its matrix for mass in mass damper spring system. actually i am working with some kind of fluid and vehicle dynamics interface. Yes this matrix is gonna be multiplied by a vector

I don't know if you've noticed, but if you keep giving vague descriptions, then I'm only able to give vague answers as well

There is a thread explaining how to provide information, so that this kind of vague exchange of information doesn't happen: http://www.cfd-online.com/Forums/ope...-get-help.html

Best regards,
Bruno

[santiagomarquezd]

Originally Posted by 13msmemusman

Hi guys i have a problem related to matrices. I have to define and write a matrix in which every element have different dimensions. for example 1st element has dimensions in kilogram 2nd in meters 3rd in second like that. Please guide me how can i do that.

It is not possible in the present versions of FOAM.

Regards!

[tjliang]

Hello Everyone,


my problem is a litle bit related to the Matrix problem. I want to have one field value obtained from a two-dimensional lookup table, which means the value is dependent on two variables. Is it possible that I insert values into the Matrix and look up and interpolate among them? I know it may be quite wrong, any hints from you will be appreciated by me. Thank you.


Best regards,


Peng

[klausb]

I want to multiply two matrices E and F to obtain G so G = E*F. I tried the following, I don't get compile errors but from the line //Compute G = E * F onwards, things don't work. Here's my code:

    // Set the size of the matrices
    const label N = 4; // matrix size
    
    // Declare and initialize lduMatrices E, F, and G
    RectangularMatrix <scalar> E(N,N);
    RectangularMatrix <scalar> F(N,N);
    RectangularMatrix <scalar> G(N,N);

    // Set coefficients for matrix E diagonal
    scalar diagonalValuesE[] = {1.0, 2.0, 3.0, 4.0};
    for (label i = 0; i < N; ++i)
    {
        E[i][i] = diagonalValuesE[i];
    }

    // Set coefficients for matrix F diagonal
    scalar diagonalValuesF[] = {5.0, 6.0, 7.0, 8.0};
    for (label i = 0; i < N; ++i)
    {
        F[i][i] = diagonalValuesF[i];
    }

    //Compute G = E * F
     G=E*F; // THIS DOESN'T WORK I THINK, THERE IS A FUNCTION CALLED 
                 //"multiply", too but I don't know how to use it
     
    // Print the diagonal element G[0][0]
     Info << "Diagonal element G[0][0]: " << G[0][0] << endl;

Regarding "multiply" see: // https://www.openfoam.com/documentati...trices_8H.html

Can someone tell me how to multiply two matrices?