Error with MSD and SDC

[jmarbues]

Hi. I was trying to run some simulations to calculate the self-diffusion coefficient via the velocity autocorrelation and the mean-square displacement function. In both approaches the simulation immediately crashes with the following error:

CUDA Error:
File: utilities/gpu_vector.cuh
Line: 83
Error code: 2
Error text: out of memory

Thank you for your time.
Kind regards, José

[brucefan1983]

You number of correlation stpes is 5 000 000, which is too large. Your sampling inverval is 5. If your time step is 1 fs, this means your maximum correlation time is 25 ns. I have never seen a diffusion problem requiring so large correlation time. You can consider decreasing the number of correlation steps, and if needed, increasing the sampling interval.

Note:
The memory required for the calculations is at least N*5000000*24 Byte based on your inputs, where N is the number of atoms

[jmarbues]

Ok yes, that solved the problem. Thank you for your help.

The formula for the memory required you gave is very useful.