Merge pull request #68 from lanl/fermirec

Changed the type to match the input matrix when calling diagonalization.

Author: cnegre

src/prg_sp2_fermi_mod.F90

@@ -363,7 +363,7 @@ function sp2_entropy_ts(D0_bml, GG, ee) result(TS)
     allocate(hh(N))
 
     ! Diagonalize D0
-    call bml_zero_matrix(bml_matrix_dense, bml_element_real, &
+    call bml_zero_matrix(bml_type, bml_element_real, &
       dp, N, N, aux_bml)
 
     call bml_diagonalize(D0_bml, hh, aux_bml)

src/prg_sp2_fermirec_mod.F90

@@ -0,0 +1,148 @@
+!> The SP2 Recursive Fermi O(N) module.
+!! \ingroup PROGRESS
+    !
+    ! This subroutine implements Niklasson's SP2 recursive fermi dirac exact 
+    ! density matrix purification algorithm.
+    !
+
+module prg_sp2_fermirec_mod
+
+  use bml   
+  use prg_normalize_mod
+  use prg_timer_mod
+  use prg_parallel_mod
+  
+  implicit none
+ 
+  private  !Everything is private by default
+  
+  integer, parameter :: dp = kind(1.0d0)
+
+  public :: prg_sp2_fermirec
+
+contains
+ 
+  !> Recursive SP2 Fermi.
+  !! \param h_bml Input Hamiltonian matrix.
+  !! \param xio_bml Input ? matrix.
+  !! \param nsteps Number of sp2 iterations.
+  !! \param nocc Number of occupied states.
+  !! \param threshold Threshold for multiplication.
+  !! \param occErrLimit Occupation error limit.
+  !! \param traceLimit Trace limit.
+  !! \param x_bml Output initial matrix.
+  !! \param mu Shifted chemical potential
+  !! \param beta Output inverse temperature.
+  subroutine prg_sp2_fermirec(h_bml, xio_bml, nsteps, nocc, threshold, occErrLimit, &
+      x_bml, mu, beta)
+
+    implicit none
+
+    type(bml_matrix_t), intent(in) :: h_bml
+    type(bml_matrix_t), intent(inout) :: x_bml
+    integer, intent(in) :: nsteps
+    real(dp), intent(in) :: nocc, threshold
+    real(dp), intent(in) :: occErrLimit
+    real(dp), intent(inout) :: mu, beta
+
+    type(bml_matrix_t) :: x1_bml, x2_bml, i_bml, xi_bml
+    type(bml_matrix_t) :: y_bml
+    real(dp) :: trdPdmu, trP0, occErr
+    real(dp) :: cnst, ofactor
+    real(dp), allocatable :: trace(:)
+    character(20) :: bml_type
+    integer :: N, M, i, cnt, NrSchultz
+    logical :: firstTime
+
+    bml_type = bml_get_type(h_bml)
+    N = bml_get_N(h_bml)
+    M = bml_get_M(h_bml)
+
+    allocate(trace(2))
+
+    call bml_identity_matrix(bml_type, bml_element_real, dp, N, M, i_bml)
+    call bml_zero_matrix(bml_type, bml_element_real, dp, N, M, x1_bml)
+    call bml_zero_matrix(bml_type, bml_element_real, dp, N, M, x2_bml)
+    call bml_zero_matrix(bml_type, bml_element_real, dp, N, M, xi_bml)
+    call bml_zero_matrix(bml_type, bml_element_real, dp, N, M, y_bml)
+
+    occErr = 1.0_dp
+    cnt = 0
+    firstTime = .true.
+
+    do while (occErr .gt. occErrLimit)
+
+      !Calculate beta before entering this subroutine
+      !beta = 1.0_dp/(kB*T) ! Temp in K
+
+      ! Is this a normalization? 
+      ! yes, make as separate routine in normalize_mod
+      ! P0 = 0.5*II - cnst*(H0-mu0*II)
+      cnst = beta/(2**(2+nsteps))
+      call bml_copy(h_bml, x_bml)
+      call bml_add_deprecated(1.0_dp, x_bml, -mu, i_bml, threshold)
+      call bml_add_deprecated(-cnst, x_bml, 0.5_dp, i_bml, threshold)
+      call bml_copy(xio_bml, xi_bml) !XI = XIO
+
+      do i = 1, nsteps
+        call bml_multiply_x2(x_bml, x2_bml, threshold, trace)
+        ! Y = 2*(P02-P0) + II
+        call bml_copy(x2_bml, y_bml)
+        call bml_add_deprecated(1.0_dp, y_bml, -1.0_dp, x_bml, threshold)
+        call bml_add_deprecated(2.0_dp, y_bml, 1.0_dp, i_bml, threshold)
+
+        if (firstTime .eqv. .true.) then
+          call bml_inverse(y_bml, xi_bml)
+        else
+          NrSchulz = 4
+          do i = 1, NrSchulz
+            call bml_copy(xi_bml, xtmp_bml)
+            call bml_multiply(xtmp_bml, y_bml, x_bml, &
+              -1.0_dp, 0.0_dp)
+            call bml_multiply(x_bml, xtmp_bml, xi_bml, &
+               1.0_dp, 2.0_dp) 
+          enddo
+        endif
+        firsttime = .false.
+
+
+        if (j == 1) then
+          call bml_copy(xi_bml, xio_bml)
+        endif
+
+        call bml_multiply(xi_bml, x2_bml, x_bml, 1.0_dp, 0.0_dp, threshold)
+      enddo
+
+      ! Need to write sumDiagonal routine?
+      trdPdmu = bml_sumDiagonal(x_bml)
+      trP0 = trdPdmu
+      ! Need to write sumX2 routine?
+      trdPdmu = trdPdmu - bml_sumX2(x_bml) ! sum x(i,j)**2
+
+      trdPdmu = beta * trdPdmu
+      mu = mu + (nocc - trP0)/trdPdmu
+      occErr = abs(trP0 - nocc)
+      cnt = cnt + 1
+      if (cnt .ge. MaxIt) then
+        occErr = 0.0_dp
+      endif
+    enddo
+
+    ! Adjust occupation
+    call bml_copy(i_bml, x1_bml)
+    call bml_add_deprecated(1.0_dp, x1_bml, -1.0_dp, x_bml, threshold)
+    call bml_multiply(x_bml, x1_bml, xi_bml, 1.0_dp, 0.0_dp, threshold)
+    ofactor = ((nocc - trP0)/trdPmu) * beta
+    call bml_add_deprecated(1.0_dp, x_bml, ofactor, xi_bml, threshold)
+
+    deallocate(trace)
+
+    call bml_deallocate(xi_bml)
+    call bml_deallocate(i_bml)
+    call bml_deallocate(x1_bml)
+    call bml_deallocate(x2_bml)
+    call bml_deallocate(y_bml)
+
+  end subroutine prg_sp2_fermirec
+
+  end module prg_sp2_fermirec_mod