[ariorus]

Hello.

I'd like to have an utility which creates in output a selected field variable file for a given boundary of the domain.

It cannot be that hard, I know.

But I'm a novel c++ user, and it is not easy to find inside the code what you need...

For example for pressure field p (volScalarField) on the boundary "patchlabel" I'm supposed to have all the data in p.boundaryField()[patchLabel], but which function do I have to use to read actually the field values?

I hope in a good hint...

Thank you so much.

[ariorus]

I'm not sure it's clean and correct:

scalarField pp = p.boundaryField()[patchLabel];

Then I can access the field values by
pp[i];

Anyway thank you for any other comment.

[hjasak]

Close. Try:

const scalarField& pp = p.boundaryField()[patchLabel];

and pp[i] if you do NOT want to change the values.

If you do want to change them, use:

scalarField& pp = p.boundaryField()[patchLabel];

Please notice the extra "&" - in your code you've made a copy of the patch field, which is not a good idea.

Enjoy,

Hrv

[ariorus]

Ok.
Thank you very much.

By the way, I hope not to well out of your kindness too much, how can I get the dimension of my scalar field, namely "the lenght" of pp?

I need to read all pp[i] and I think I can use something like:

for (int ic=0; ic<??; ic++)
{...pp[ic]... }

or in a more smart way

forall (..??.. ic)
{...pp[ic]...}

But I don't know what to put in ??...

Thanks again.

[eugene]

p.dimensions() should do it.
or do you mean size? p.size()

To loop through any list use the "forAll" macro:
forAll(pp, counter)
{
pp[counter]=...
}

Very useful, very neat.

[hjasak]

pp.size() (dimensions mean dimension set [mass length time etc] which is for geometric fields and dimensioned types).

So:

forAll (pp, ppI)
{
pp[ppI] = ...;
}
(thanks Eugene and sorry to butt in)

which expands to
(for label ppI = 0; ppI < pp.size(); ppI++)
{
etc
}

This is very basic stuff, I recommend some digging through the code and examples to help you with more programming.

Hrv

[ariorus]

Thanks Eugene, thanks Hrvoje.

My problem is just to find out where and in which way the basic operations are placed in the code..

I'm using Doxygen documentation but I often have problems to identify the member function I need.
In this example I tried also to access the source code of some macros such as "sum" or "forAll" which could help me to understand, I think. But I didn't manage to find them.

Do you think there are some examples or some parts of the code to have a look at in order to catch a little deeper the structure of OpenFoam programming? It would be very useful to me..

[jballen]

Hi

I am solving a flow inside a domain consisting of a rectangular box. I would like to know how to determine the length width and height of this domain in a piece of code.
Thanks
Jeff

[msrinath80]

Oh, I forgot. This portion[1] goes between these lines:

const fvPatchList& patches = mesh.boundary();

forAll(patches, patchI)


[1]:
forAll(U.boundaryField(), patchI)
{
if (U.boundaryField()[patchI].fixesValue())
{
Uav += average(U.boundaryField()[patchI]);
}
}