0 Tutorial : write a program which prints i|H|j for any pair (i, j)

Anthony Scemama edited this page 2018-07-20 10:46:08 +02:00

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1. Create a new module, named PrintHij for example, which needs the module Determinants :

qp_module.py create -n "PrintHij" Determinants

2. Go into the $QP_ROOT/src/PrintHij module and rename the file PrintHij.main.irp.f as PrintHij.irp.f

cd $QP_ROOT/src/PrintHij
mv PrintHij.main.irp.f PrintHij.irp.f

3. Edit PrintHij.irp.f as follows

     program print_matrix_element
       use bitmasks
       implicit none

       integer(bit_kind) :: det_i(N_int,2)
       integer(bit_kind) :: det_j(N_int,2)

       double precision  :: hij

       integer           :: i,j

       print *,  'Determinant <i| ?'
       read(*,*) i
       det_i(1:N_int, 1:2) = psi_det(1:N_int, 1:2, i)

       print *,  'Determinant |j> ?'
       read(*,*) j
       det_j(1:N_int, 1:2) = psi_det(1:N_int, 1:2, j)

       call i_H_j(det_i, det_j, N_int, hij)
       print *,  '<i|H|j> = ', hij

     end

4. Run ninja to compile the PrintHij program

5. Run make in the $QP_ROOT/ocaml directory such that it rebuilds also the OCaml binaries

6. You’re done! Take an EZFIO directory containing a wave function and set the read_wf flag to true, then

qp_run PrintHij test.ezfio