where to allocate array for particle properties

Hi everybody,

I'd like to allocate memory in a fix for an array to store certain particle properties.

I thought I define the array within the headerfile with following line:

double *particle_prop_;

Then I wanted to allocate memory in the constructor of the fix, like:

int nlocal = atom->nlocal;
particle_prop_ = (double*)memory->create_1d_double_array(nlocal, 0,"particle_prop_");

and later I wanted to use the array in a method for some calculations.

... But the simulation crashes by segmentation faults at some mysterious lines somewhere in the code, sometimes within the variable.cpp and sometimes within the region.cpp.

Now I realised that nlocal is not yet initialized within the constructor of my fix, so the allocation process did not work.
Then, I moved the memory allocation from the constructor part of the fix to the method, where I need the array and wrote

if (Nsteps==0)
{
particle_prop_ = (double*)memory->create_1d_double_array(nlocal, 0,"particle_prop_");
Nsteps++;
}

and initialised Nsteps in the constructor part with 0, so that the allocation-process is envoked only on the first time, the method is called.

But that way didn't work either, now I get the error:
ERROR on proc 0: Failed to allocate -248 bytes for array particle_prop_

What is the problem - how should I proceed?

Many thanks in advance,

kind regards,

Sebastian