[Democritus]

Hello Dear Foamers~!

In my project i want to define a complex source field. For example, I want solve the equation:

volScalarField p;
volScalarField sourceField;
solve( fvm::laplacian( p ) == sourceField )

Furthermore, the source filed is a complex space function, for example, such as

f(x, y, z) = sin(x) * cos(y) * z

Here is my though about this problem:
1. one field of every cell center's position must be obtained, that can be achieved by:

volVectorField centerPostions = mesh.C();

2. there must be a method in order to read through every element of the field. such as:

for(i = first_element_index, i <= last_element_index, i++)
{
     sourceField.element(i) = sin( centerPosition.element(i).x() ) * .....
}

I was blocked in the second step, dear foamers, is there a method can accomplish that?
I am open for every advices!
Thanks very much!

[Democritus]

As every field can be seen as UList<Type>, so it comes to me that if method inside the class template can help.

[akidess]

You are looking "forAll" (search the forum for this keyword).

[Democritus]

Thank you very much for your response!
After searching and studying the threads of the forum with key word "forAll". I have got the basic understanding of the macro "forAll". What's more, I have developed my own "manual" method in order to scan a field:

    Foam::vector * i;
    Foam::label j = 0;
    volVectorField position = mesh.C();

    Info << "\n the first method of scanning the field " << endl;
    for ( i = position.begin(); i <= position.end(); i++) {
      Info << "\n the cell " << j << "'s position is " << position[j] << endl;
      j++;
      if (j == 5) {
        break;
      }
    }

    Info<< "\n the second method of scanning the field " << endl;
    j = 0;
    forAll( position, elmtID ){
      Info << "\n the cell " << elmtID << "'s position is " << position[elmtID] << endl;
      j++;
      if (j == 5) {
        break;
      }
    }

and the result is quite well:

the first method of scanning the field

the cell 0's position is (1.25e-05 0.000125 0.0001)

the cell 1's position is (3.75e-05 0.000125 0.0001)

the cell 2's position is (6.25e-05 0.000125 0.0001)

the cell 3's position is (8.75e-05 0.000125 0.0001)

the cell 4's position is (0.0001125 0.000125 0.0001)

the second method of scanning the field

the cell 0's position is (1.25e-05 0.000125 0.0001)

the cell 1's position is (3.75e-05 0.000125 0.0001)

the cell 2's position is (6.25e-05 0.000125 0.0001)

the cell 3's position is (8.75e-05 0.000125 0.0001)

the cell 4's position is (0.0001125 0.000125 0.0001)

Originally Posted by akidess

You are looking "forAll" (search the forum for this keyword).