Example: Restart the SCF¶

#! /bin/sh

# This example shows how you can continue with an unfinished calculation. It
# consists of two runs. After the first run the RUNKF file is saved, and the
# renamed file is used in the second run. The second run is almost a copy for
# the first, except for the Restart key. It is also possible to restart from a
# smaller basis set (provided that the functions are contained in the bigger
# basis set). Finally you can also restart from a density matrix, but this
# should be explicitly saved (unlike the orbitals).

# ----------------------------- first run --------------------------

AMS_JOBNAME=BChain $AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain

   NumericalQuality Good

   skip dos

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   DIIS
      NCycleDamp 0
      DiMix 0.5
      Adaptable false ! Otherwise it converges to a spin-restricted solution
   End

   Basis
      Type TZ2P
      Core Large
   End
EndEngine

eor

# --- let us first try a EngineRestart

AMS_JOBNAME=restart_engine $AMSBIN/ams <<eor

Task SinglePoint

EngineRestart BChain.results/band.rkf

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain restart via EngineRestart

   NumericalQuality Good

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None


   Basis
      Type TZ2P
      Core Large
   End
EndEngine

eor


# ----------------------------- second run --------------------------

AMS_JOBNAME=restart_1 $AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain restart

   NumericalQuality Good

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   Restart
      File BChain.results/band.rkf
      scf
   end

   Basis
      Type TZ2P
      Core Large
   End
EndEngine

eor

# ----------------------------- third run --------------------------

AMS_JOBNAME=BChain_SZ $AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain bas_SZ

   NumericalQuality Good

   Save DensityMatrix

   skip dos

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   DIIS
      NCycleDamp 0
      DiMix 0.3
      Adaptable false ! Otherwise it converges to a spin-restricted solution
   End

   Basis
      Type SZ
      Core Large
   End
EndEngine 

eor

# ----------------------------- fourth run --------------------------


AMS_JOBNAME=restart_2 $AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain restart bas_SZ from density matrix

   NumericalQuality Good

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   Restart
      File BChain_SZ.results/band.rkf
      scf
      useDensityMatrix true
   end

   Basis
      Type SZ
      Core Large
   End
EndEngine
eor


# ----------------------------- fifth run --------------------------

AMS_JOBNAME=BChain_TZ2P $AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain restart bas=TZ2P from orbitals

   NumericalQuality Good

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   Restart
      File BChain_SZ.results/band.rkf
      scf
      useDensityMatrix false
   end

   Basis
      Type TZ2P
      Core Large
   End
EndEngine

eor

# ----------------------------- sixth run --------------------------

$AMSBIN/ams <<eor

Task SinglePoint

System
   Lattice [Bohr]
      4.0 0.0 0.0
   End
   Atoms [Bohr]
      B 0.0 0.0 0.0 
   End
End

Engine Band 
   Title B chain restart bas=TZ2P from density matrix (bas_SZ)

   NumericalQuality Good

   XC
      GGA Becke Perdew
   END

   UNRESTRICTED
   Relativity Level=None

   Restart
      File BChain_SZ.results/band.rkf
      scf
      useDensityMatrix true
   end

   Basis
      Type TZ2P
      Core Large
   End
EndEngine
eor