[cosimobianchini]

Hi Foamers,
sorry because this might be a trivial question.
I would like to have a look at the piece of code where gSum is implemented but I was not able to find it. Where is this function implemented?

I need to understand if in such case:

gSum(volScalarField.boundaryField());

processor boundaries are included in the sum or not.
Thanks in advance,
Cosimo

[leonardo13]

gSum is implemented in FieldFieldFunctions.C as a template function.



First the G_UNARY_FUNCTION is defined:


#define G_UNARY_FUNCTION(ReturnType, gFunc, func, rFunc) \

template<template<class> class Field, class Type> \

ReturnType gFunc(const FieldField<Field, Type>& f) \

{ \


ReturnType res = func(f); \

reduce(res, rFunc##Op<ReturnType>()); \

return res; \

}\


Then, gSum is defined as


G_UNARY_FUNCTION(Type, gSum, sum, sum)


Replacing the function imputs in the template the result is


Type gFunc(const FieldField<Field, Type>& f) {
Type res = sum(f);
reduce(res, sumOp<Type>());
return res;
}



Remember that reduce is a function to integrate operations from all the processors (parallel run). So, when using gSum, we are really using "reduce" backstage.



I know this thread is old, but hope some find help!

[sadsid]

Can we apply gSum on a list of scalars or vectors?
I tried the following code:

forAll(mesh.C(),i)
{
m_[Pstream::myProcNo()][i] = gSum((m[i].internalField()*mesh.V())());
}

But it gives error. If I use gSum((m.internalField()*mesh.V())()); without "[i]" then it does not give error but allocate a single value to the whole list of "m".

What I want to achieve: The summation should be performed on a per-element basis. That is the ith element of the array "m" are summed into the ith element of the resulting array (here m_).

Originally Posted by leonardo13

gSum is implemented in FieldFieldFunctions.C as a template function.



First the G_UNARY_FUNCTION is defined:


#define G_UNARY_FUNCTION(ReturnType, gFunc, func, rFunc) \

template<template<class> class Field, class Type> \

ReturnType gFunc(const FieldField<Field, Type>& f) \

{ \


ReturnType res = func(f); \

reduce(res, rFunc##Op<ReturnType>()); \

return res; \

}\


Then, gSum is defined as


G_UNARY_FUNCTION(Type, gSum, sum, sum)


Replacing the function imputs in the template the result is


Type gFunc(const FieldField<Field, Type>& f) {
Type res = sum(f);
reduce(res, sumOp<Type>());
return res;
}



Remember that reduce is a function to integrate operations from all the processors (parallel run). So, when using gSum, we are really using "reduce" backstage.



I know this thread is old, but hope some find help!