MCTDH-X forum

MCTDH-X Usage => Main Program Usage => Topic started by: yeongjingwak on November 27, 2017, 10:31:03 AM

Title: Estimation of Memory in Relaxation.
Post by: yeongjingwak on November 27, 2017, 10:31:03 AM

Hello, I joined this community 2 months ago.

I'm wondering how to estimate the memory capability of the computation.

When I run relaxation program, It seems that it mainly depends on the value (N+M-1 over N).

But the allocated memory scale grows much faster than that when I changed N and M values.

When other parameters are fixed, how does the allocated memory size depend on M and N?

Title: Re: Estimation of Memory in Relaxation.
Post by: mctdhb on December 04, 2017, 09:18:03 AM

Hi there!

The memory needed for a computation with MCTDH-B for the coefficients is (N+M-1 over N)*(16 bytes [double precision complex])*(Dimension of Krylov subspace used for the integrator). The size of the Krylov subspace is adaptive, i.e., it depends on the particular problem studied; but it can be controlled using the "Minimal_Krylov" and "Maximal_Krylov" inputs in the MCTDHX.inp file.

In addition, M*N_g*[O(10)]*(16 bytes [double precision complex]) of memory is needed for the solution of the orbital equation.

Regards,
Axel