MCTDHX forum
MCTDHX Usage => Main Program Usage => Topic started 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+M1 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?

Hi there!
The memory needed for a computation with MCTDHB for the coefficients is (N+M1 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