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)?
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.