LCAO buffer

Description

Change the buffer to be from single precision to be double precision.

This increases the memory footprint but makes that the results remain identical when changing the parallelization. The result of the test finite_systems_3d/01-carbon become identical for non-MPI and MPI builders when we do this.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.

src/scf/lcao.F90

@@ -96,8 +96,11 @@ module lcao_oct_m
     logical                 :: derivative
     integer,    allocatable :: cst(:, :)
     integer,    allocatable :: ck(:, :)
-    real(4),    allocatable :: dbuff(:, :, :, :) !< single-precision buffer
-    complex(4), allocatable :: zbuff(:, :, :, :) !< single-precision buffer
+    real(4),    allocatable :: dbuff_single(:, :, :, :) !< single-precision buffer
+    complex(4), allocatable :: zbuff_single(:, :, :, :) !< single-precision buffer
+    FLOAT,      allocatable :: dbuff(:, :, :, :) 
+    CMPLX,      allocatable :: zbuff(:, :, :, :) 
+    logical                 :: save_memory
     logical                 :: initialized_orbitals
     FLOAT                   :: orbital_scale_factor
 
@@ -257,6 +260,17 @@ contains
       this%complex_ylms = .false.
     end if
 
+    !%Variable LCAOSaveMemory
+    !%Type logical
+    !%Default false
+    !%Section SCF::LCAO
+    !%Description
+    !% If set to true, the LCAO will allocate extra memory needed in single precision instead of 
+    !% double precision.
+    !%End
+    call parse_variable(namespace, 'LCAOSaveMemory', .false., this%save_memory)
+
+
     if (debug%info .and. mpi_grp_is_root(mpi_world)) then
       call io_mkdir('debug/lcao', namespace)
       iunit_o = io_open('debug/lcao/orbitals', namespace, action='write')
@@ -858,6 +872,8 @@ contains
     SAFE_DEALLOCATE_A(this%ddim)
     SAFE_DEALLOCATE_A(this%cst)
     SAFE_DEALLOCATE_A(this%ck)
+    SAFE_DEALLOCATE_A(this%dbuff_single)
+    SAFE_DEALLOCATE_A(this%zbuff_single)
     SAFE_DEALLOCATE_A(this%dbuff)
     SAFE_DEALLOCATE_A(this%zbuff)