[ashishmagar600]

Hello guys,

I will describe my problem briefly.

In my modified code, I am doing certain computations (such as averaging and stuff) on some pipes. The mesh is huge and I wanted to decompose, such that the whole pipe section comes under one processor. This was done.

I wanted to declare some variables which are to be used only on the same processor as the pipe and to be accessed at different times during an outer iteration (maybe piso).

I was trying to do something like this:

       if(Pstream::MyProcNo() == 1){
             int a[100];
       }

//Some solving to be done everywhere

       if(Pstream::MyProcNo() == 1){
             a[50] = 5;
       }

Here, it would say

a is not declared in this scope

I have made sure that both the steps cannot be clubbed together, as somethings necessary are done in between.

Is there some way I can do this, or am I doing this completely wrong?

Thanks

[einstein_zee]

Originally Posted by ashishmagar600

Hello guys,

I will describe my problem briefly.

In my modified code, I am doing certain computations (such as averaging and stuff) on some pipes. The mesh is huge and I wanted to decompose, such that the whole pipe section comes under one processor. This was done.

I wanted to declare some variables which are to be used only on the same processor as the pipe and to be accessed at different times during an outer iteration (maybe piso).

I was trying to do something like this:

       if(Pstream::MyProcNo() == 1){
             int a[100];
       }

//Some solving to be done everywhere

       if(Pstream::MyProcNo() == 1){
             a[50] = 5;
       }

Here, it would say

a is not declared in this scope

I have made sure that both the steps cannot be clubbed together, as somethings necessary are done in between.

Is there some way I can do this, or am I doing this completely wrong?

Thanks

Hey there,

The point is once your variable is defined enclosed in curly braces its lifetime will come to an end once the control reaches to the end of the brace. In case you define a variable like this you need to make sure that you finish your job with that extra variable inside that territory. But it seems you want to have it for later use. Hence, you may allocate dynamically your variable with the help of a small function giving the size of your variable to be zero for other procs and giving the desired size for your specific proc.
exp.

void assign(int& arraySize, int nproc, int procID)
{
    if(procID == 1) // assuming your case
    {
        arraySize = 100;
    }
    else
    {
        arraySize = 0;
    }
}

and then in your main code you may allocate the variable like this:

int arraySize;
assign(arraySize, nProc, procID);
int* a = new int[arraySize];