Introducing Cholesky-decomposed SCF

src/ao_two_e_ints/cholesky.irp.f

@@ -0,0 +1,100 @@
+BEGIN_PROVIDER [ integer, cholesky_ao_num_guess ]
+ implicit none
+ BEGIN_DOC
+ ! Number of Cholesky vectors in AO basis
+ END_DOC
+
+ integer :: i,j,k,l
+ double precision :: xnorm0, x, integral
+ double precision, external :: ao_two_e_integral
+
+ cholesky_ao_num_guess = 0
+ xnorm0 = 0.d0
+ x = 0.d0
+ do j=1,ao_num
+   do i=1,ao_num
+     integral = ao_two_e_integral(i,i,j,j)
+     if (integral > ao_integrals_threshold) then
+       cholesky_ao_num_guess += 1
+     else
+       x += integral
+     endif
+   enddo
+ enddo
+ print *, 'Cholesky decomposition of AO integrals'
+ print *, '--------------------------------------'
+ print *, ''
+ print *, 'Estimated Error: ', x
+ print *, 'Guess size: ', cholesky_ao_num_guess, '(', 100.d0*dble(cholesky_ao_num_guess)/dble(ao_num*ao_num), ' %)'
+
+END_PROVIDER
+
+ BEGIN_PROVIDER [ integer, cholesky_ao_num ]
+&BEGIN_PROVIDER [ double precision, cholesky_ao, (ao_num, ao_num, cholesky_ao_num_guess) ]
+ use mmap_module
+ implicit none
+ BEGIN_DOC
+ ! Cholesky vectors in AO basis: (ik|a):
+ ! <ij|kl> = (ik|jl) = sum_a (ik|a).(a|jl)
+ END_DOC
+
+ type(c_ptr) :: ptr
+ integer :: fd, i,j,k,l, rank
+ double precision, pointer :: ao_integrals(:,:,:,:)
+ double precision, external :: ao_two_e_integral
+
+ ! Store AO integrals in a memory mapped file
+ call mmap(trim(ezfio_work_dir)//'ao_integrals', &
+   (/ int(ao_num,8), int(ao_num,8), int(ao_num,8), int(ao_num,8) /), &
+   8, fd, .False., ptr)
+ call c_f_pointer(ptr, ao_integrals, (/ao_num, ao_num, ao_num, ao_num/))
+
+ double precision :: integral
+ logical, external :: ao_two_e_integral_zero
+ !$OMP PARALLEL DO DEFAULT(SHARED) PRIVATE(i,j,k,l, integral) SCHEDULE(dynamic)
+ do l=1,ao_num
+  do j=1,l
+   do k=1,ao_num
+    do i=1,k
+     if (ao_two_e_integral_zero(i,j,k,l)) cycle
+     integral = ao_two_e_integral(i,k,j,l)
+     ao_integrals(i,k,j,l) = integral
+     ao_integrals(k,i,j,l) = integral
+     ao_integrals(i,k,l,j) = integral
+     ao_integrals(k,i,l,j) = integral
+    enddo
+   enddo
+  enddo
+ enddo
+ !$OMP END PARALLEL DO
+
+ ! Call Lapack
+ cholesky_ao_num = cholesky_ao_num_guess
+ call pivoted_cholesky(ao_integrals, cholesky_ao_num, ao_integrals_threshold, ao_num*ao_num, cholesky_ao)
+ print *, 'Rank: ', cholesky_ao_num, '(', 100.d0*dble(cholesky_ao_num)/dble(ao_num*ao_num), ' %)'
+
+ ! Remove mmap
+ double precision, external :: getUnitAndOpen
+ call munmap( &
+   (/ int(ao_num,8), int(ao_num,8), int(ao_num,8), int(ao_num,8) /), &
+   8, fd, ptr)
+ open(unit=99,file=trim(ezfio_work_dir)//'ao_integrals')
+ close(99, status='delete')
+
+END_PROVIDER
+
+BEGIN_PROVIDER [ double precision, cholesky_ao_transp, (cholesky_ao_num, ao_num, ao_num) ]
+ implicit none
+ BEGIN_DOC
+! Transposed of the Cholesky vectors in AO basis set
+ END_DOC
+ integer :: i,j,k
+ do j=1,ao_num
+  do i=1,ao_num
+   do k=1,ao_num
+    cholesky_ao_transp(k,i,j) = cholesky_ao(i,j,k)
+   enddo
+  enddo
+ enddo
+END_PROVIDER
+

src/ao_two_e_ints/map_integrals.irp.f

@@ -486,7 +486,7 @@ subroutine get_ao_two_e_integrals(j,k,l,sze,out_val)
   PROVIDE ao_two_e_integrals_in_map ao_integrals_map
 
   if (ao_one_e_integral_zero(j,l)) then
-    out_val = 0.d0
+    out_val(1:sze) = 0.d0
     return
   endif
 

src/hartree_fock/fock_matrix_hf.irp.f

@@ -15,6 +15,12 @@
  double precision, allocatable  :: ao_two_e_integral_alpha_tmp(:,:)
  double precision, allocatable  :: ao_two_e_integral_beta_tmp(:,:)
 
+ if (.True.) then   ! Use Cholesky-decomposed integrals
+   ao_two_e_integral_alpha(:,:) = ao_two_e_integral_alpha_chol(:,:)
+   ao_two_e_integral_beta (:,:) = ao_two_e_integral_beta_chol (:,:)
+
+ else ! Use integrals in AO basis set
+
    ao_two_e_integral_alpha = 0.d0
    ao_two_e_integral_beta  = 0.d0
    if (do_direct_integrals) then
@@ -150,6 +156,81 @@
      !$OMP END PARALLEL
 
    endif
+ endif
+
+END_PROVIDER
+
+ BEGIN_PROVIDER [ double precision, ao_two_e_integral_alpha_chol, (ao_num, ao_num) ]
+&BEGIN_PROVIDER [ double precision, ao_two_e_integral_beta_chol ,  (ao_num, ao_num) ]
+ use map_module
+ implicit none
+ BEGIN_DOC
+ ! Alpha and Beta Fock matrices in AO basis set
+ END_DOC
+
+ integer :: m,n,l,s,j
+ double precision :: integral
+ double precision, allocatable :: X(:), X2(:,:,:,:), X3(:,:,:,:)
+
+ allocate (X(cholesky_ao_num))
+
+
+ ! X(j) = \sum_{mn} SCF_density_matrix_ao(m,n) * cholesky_ao(m,n,j)
+ call dgemm('T','N',cholesky_ao_num,1,ao_num*ao_num,1.d0,            &
+     cholesky_ao, ao_num*ao_num,                                     &
+     SCF_density_matrix_ao, ao_num*ao_num,0.d0,                      &
+     X, cholesky_ao_num)
+!
+
+ ! ao_two_e_integral_alpha(m,n) = \sum_{j} cholesky_ao(m,n,j) * X(j)
+ call dgemm('N','N',ao_num*ao_num,1,cholesky_ao_num, 1.d0,           &
+     cholesky_ao, ao_num*ao_num,                                     &
+     X, cholesky_ao_num, 0.d0,                                       &
+     ao_two_e_integral_alpha_chol, ao_num*ao_num)
+
+ deallocate(X)
+
+ ao_two_e_integral_beta_chol = ao_two_e_integral_alpha_chol
+
+
+ allocate(X2(ao_num,ao_num,cholesky_ao_num,2))
+
+! ao_two_e_integral_alpha_chol (l,s) -= cholesky_ao(l,m,j) * SCF_density_matrix_ao_beta (m,n) * cholesky_ao(n,s,j)
+
+ call dgemm('N','N',ao_num,ao_num*cholesky_ao_num,ao_num, 1.d0,      &
+     SCF_density_matrix_ao_alpha, ao_num,                            &
+     cholesky_ao, ao_num, 0.d0,                                      &
+     X2(1,1,1,1), ao_num)
+
+ call dgemm('N','N',ao_num,ao_num*cholesky_ao_num,ao_num, 1.d0,      &
+     SCF_density_matrix_ao_beta, ao_num,                             &
+     cholesky_ao, ao_num, 0.d0,                                      &
+     X2(1,1,1,2), ao_num)
+
+ allocate(X3(ao_num,cholesky_ao_num,ao_num,2))
+
+ do s=1,ao_num
+  do j=1,cholesky_ao_num
+   do m=1,ao_num
+    X3(m,j,s,1) = X2(m,s,j,1)
+    X3(m,j,s,2) = X2(m,s,j,2)
+   enddo
+  enddo
+ enddo
+
+ deallocate(X2)
+
+ call dgemm('N','N',ao_num,ao_num,ao_num*cholesky_ao_num, -1.d0,     &
+     cholesky_ao, ao_num,                                            &
+     X3(1,1,1,1), ao_num*cholesky_ao_num, 1.d0,                      &
+     ao_two_e_integral_alpha_chol, ao_num)
+
+ call dgemm('N','N',ao_num,ao_num,ao_num*cholesky_ao_num, -1.d0,     &
+     cholesky_ao, ao_num,                                            &
+     X3(1,1,1,2), ao_num*cholesky_ao_num, 1.d0,                      &
+     ao_two_e_integral_beta_chol, ao_num)
+
+ deallocate(X3)
 
 END_PROVIDER
 

src/utils/linear_algebra.irp.f

@@ -1854,7 +1854,7 @@ do k = 1, N
 end do
 ! TODO: It should be possible to use only one vector of size (1:rank) as a buffer
 ! to do the swapping in-place
-U = 0.00D+0
+U(:,:) = 0.00D+0
 do k = 1, N
   l = piv(k)
   U(l, :) = A(1:rank, k)