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--- exercises:2015_ethz_mmm:ls_scf [2015/03/05 13:33] – vondele
+++ exercises:2015_ethz_mmm:ls_scf [2015/03/05 13:54] – [Input File] vondele
@@ Line 37: / Line 37: @@
 ===== Input File =====
 <code - 2d_polymer.inp>
+! Number of unit cell replications, increase this to create a large polymer.
+@SET NREPX 1
+@SET NREPY 1
 &GLOBAL
   PROJECT 2d_polymer
@@ Line 44: / Line 48: @@
 &FORCE_EVAL
   &DFT
+    ! linear scaling SCF
     &LS_SCF
-      EPS_FILTER 1E-5  ! threshold used to determine sparsity
+      ! TRS4, does not need an estimate for the chemical potential
-      MU         -0.15 ! chemical potential, an energy from within in the HOMO-LUMO gap
+      PURIFICATION_METHOD TRS4
+      ! threshold used to determine sparsity and thus speed and accuracy
+      EPS_FILTER 1E-5
+      ! convergence for the SCF
+      EPS_SCF    1E-5
+      ! chemical potential, an energy from within in the HOMO-LUMO gap
+      MU         -0.15
+      S_PRECONDITIONER ATOMIC
+    &END
+    ! traditional SCF, diagonalization by default
+    &SCF
     &END
     &QS
-      LS_SCF  ! Turns on linear scaling DFT. Comment this line to run with normal SCF.
+      LS_SCF  ! Turns on linear scaling DFT. Comment this line to run with standard SCF.
-! =============================================================================================
+      ! =============================================================================================
-! === Description of Hamiltonian (Density Functional Tight Binding + Particle Meshed Ewald) ===
+      ! === Description of Hamiltonian (Density Functional Tight Binding + Smooth Particle Meshed Ewald) ===
       METHOD DFTB
       &DFTB
@@ Line 61: / Line 77: @@
         DISPERSION         T
         &PARAMETER
-          PARAM_FILE_PATH  ./dftb_params/scc
+          PARAM_FILE_PATH  ./DFTB/scc
           PARAM_FILE_NAME  scc_parameter
           UFF_FORCE_FIELD  uff_table
@@ Line 67: / Line 83: @@
       &END DFTB
     &END QS
     &POISSON
       &EWALD
        EWALD_TYPE SPME
-       GMAX 160
+       ! scale the number of points with the system size, roughly 1pt/A.
+       GMAX 40*${NREPX} 40*${NREPY} 40
        O_SPLINE 5
       &END EWALD
     &END POISSON
-! ==============================End of Hamiltonian Description ================================
+   ! ==============================End of Hamiltonian Description ================================
-! =============================================================================================
+   ! =============================================================================================
   &END DFT
-! Number of unit cell replications, increase this to create a large polymer.
-@SET NREP 1
   &SUBSYS
     &CELL
+      ! a 2D system, z-direction is non-periodic
       ABC 23.577999 40.8383 30
-      MULTIPLE_UNIT_CELL 1 ${NREP} 1
+      MULTIPLE_UNIT_CELL ${NREPX} ${NREPY} 1
     &END CELL
     &TOPOLOGY
-      MULTIPLE_UNIT_CELL 1 ${NREP} 1
+      MULTIPLE_UNIT_CELL ${NREPX} ${NREPY} 1
     &END
     &COORD
@@ Line 94: / Line 111: @@
   &END SUBSYS
 &END FORCE_EVAL
 </code>