Hi,

I’m now using Psi4 to evaluate matrix elements, and I need to obtain the two electron integrals for the calculation. Here I use MintsHelper.mo_eri(C, C, C, C) to obtains the value. But problem came out when calculating large systems (such as anthracene dimer at 6-31G), It returns that the memory is insufficient for storing the array (I set 64G for the calculation). Therefore I’m curious whether there’s a way to reduce the size of two electron integrals from python side (like symmetry or sparse matrix)?

# Reduce two electron integrals size

It sounds like it may be worth trying DF integrals. Checking out Psi4NumPy’s DF-MP2 should give you an idea on how to accomplish this. You can find it here.