What is psi technically speaking?

klausb · October 13, 2017, 13:27

Hello,

psi appears as:

Foam::scalarField &psi,

but what is it technically speaking. A Field (=array) of values or of pointers?

I keep going in circles with value type compiler errors like:

error: cannot convert ‘Foam::scalarField {aka Foam::Field<double>}’ to ‘double**’

or

error: cannot convert ‘Foam::scalarField* {aka Foam::Field<double>*}’ to ‘double**’

Maybe someone can clarify the value type for me?

Klaus

Marpole · October 14, 2017, 18:34

scalarField is a class. It is used here to declare a reference variable psi, which is used to store an address of a scalar field.

scalarField and array are different that scalarField has more things in it but not only scalar itself. So you cannot assign a scalarField variable directly with an array unless the operator "=" has its function overwritten. The array may be assigned in a constructor such as using this sentence "scalarField & psi ("your array")".

Pointer and reference are similar as both of them store address. Reference is more safe.

October 13, 2017, 13:27	What is psi technically speaking?	#1
klausb Senior Member Klaus Join Date: Mar 2009 Posts: 250 Rep Power: 22	Hello, psi appears as: Foam::scalarField &psi, but what is it technically speaking. A Field (=array) of values or of pointers? I keep going in circles with value type compiler errors like: error: cannot convert ‘Foam::scalarField {aka Foam::Field<double>}’ to ‘double*’ or error: cannot convert ‘Foam::scalarField {aka Foam::Field<double>}’ to ‘double*’ Maybe someone can clarify the value type for me? Klaus

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October 14, 2017, 18:34		#2
Marpole Senior Member Charles Join Date: Aug 2016 Location: Vancouver, Canada Posts: 148 Rep Power: 9	scalarField is a class. It is used here to declare a reference variable psi, which is used to store an address of a scalar field. scalarField and array are different that scalarField has more things in it but not only scalar itself. So you cannot assign a scalarField variable directly with an array unless the operator "=" has its function overwritten. The array may be assigned in a constructor such as using this sentence "scalarField & psi ("your array")". Pointer and reference are similar as both of them store address. Reference is more safe.