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boundary conditions effect on Matrix coefficients

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Old   October 20, 2015, 04:28
Default boundary conditions effect on Matrix coefficients
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Hi all,

I am trying to understand how openfoam generates the matrices for the differential operators.

I have programmed a simple example for the laplacian operator:

// Define a matrix that contains the coefficients of the Laplacian

    fvScalarMatrix TEqnLaplaciano 
	   fvm::laplacian(DT, T) 

// Extract source term, matrix diagonal, upper and lower nonzero elements and their indices

    scalarField& source_  = TEqnLaplaciano.source();
    scalarField& lower_   = TEqnLaplaciano.lower();
    scalarField& upper_   = TEqnLaplaciano.upper();
    scalarField& diag_    = TEqnLaplaciano.diag();

    const unallocLabelList& l_ = TEqnLaplaciano.lduAddr().lowerAddr();
    const unallocLabelList& u_ = TEqnLaplaciano.lduAddr().upperAddr();

    Info<< "\n diagvalues:  \n " << diag_  << endl;
    Info<< "\n lowervalues: \n " << lower_ << endl;
    Info<< "\n lowerAddr:   \n " << l_     << endl;
    Info<< "\n Uppervalues: \n " << upper_ << endl;
    Info<< "\n UpperAddr:   \n " << u_     << endl;

    Info<< "\n sourcevalues:  \n " << source_  << endl;
And it gives:
* Matrix Diagonal terms
* Matrix out of diagonal terms
* Indices of the out of diagonal terms
* source terms (right hand side of the linear system) (zero in my example)

But the effect of the boundary conditions is not yet included in the matrix and source term that I get.

My question is:

How can I get the contribution (coefficients and indices) of the Boundary Conditions to the matrix coefficients (diag and out-of-diag) and to the source term?

Thanks in advance for your help.

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