[user92]

Hello everyone,

I have a question about the line of code below which I found here in Line 84


const volScalarField& p = alpha1_.db().lookupObject<volScalarField>("p");

I couldn't find a clear explanation for it, so I supposed that db stands for a database in OpenFOAM? and the code is looking for "p" in <volScalarField>

I suppose further that <volScalarField> must come from an .H file which has "p" ... is this right? if yes, is the file volScalarField.H available somewhere?

Thank you

[simrego]

Hi!


after the "database" (db) is accessed, read like this: you are looking for an object (lookupObject), which is a volScalarField type (<volScalarField>), and called p ("p").

volScalarField is a typedef, it is a "shorter notation" of GeometricField<scalar, fvPatchField, volMesh>
It is defined here:
https://openfoam.com/documentation/g...ce.html#l00059

[user92]

Originally Posted by simrego

Hi!


after the "database" (db) is accessed, read like this: you are looking for an object (lookupObject), which is a volScalarField type (<volScalarField>), and called p ("p").

volScalarField is a typedef, it is a "shorter notation" of GeometricField<scalar, fvPatchField, volMesh>
It is defined here:
https://openfoam.com/documentation/g...ce.html#l00059

Thank you I have a few more clarifications if I may ask

- I wonder if there is a link to the db where I can see all objects there including "p"?

- does <...> always describe types? or is it only a syntax for lookupObject<type>("object name")?

for example what you mentioned: GeometricField<scalar, fvPatchField, volMesh> ... does this mean that scalar, fvPatchField, volMesh are also types since they are inside <>? if yes, is is fine to have multiple types (3 in this case)?

[simrego]

You can read a bit about the objectRegistry here:
https://openfoamwiki.net/index.php/O...objectRegistry


And for the <> stuff, this is called templating. You should dig into the C++ programming language for details.

[rocco96]

Hello everybody. I would like to use the pressure value calculated by my solver (internCondensatingEvaporatingfoam) within a library (constant.C). I tried to recall it as you recommend in this post, but the solver gives errors. As I understand it I should call the p object, but any way I use to call it doesn't work. Would anyone know how to give me some advice? I don't know what to put here const volScalarField & p = <???>. LookupObject <volScalarField> ("p");

Best Regards,
Rocco