Generating QMCPACK input files

Nexus provides many ways to generate QMCPACK input. Documentation in this section is intentionally brief at present and will be expanded in the future. Currently covered features are:

• nrule

The nrule input selects a spherical quadrature rule from 1 through 8 for nonlocal pseudopotentials.

A dictionary can be used to select a different rule for each atomic species:

qmc = generate_qmcpack(
    ...,
    pseudos = ['V.ccECP.xml','O.ccECP.xml'],
    nrule   = {'V':6,'O':4},
    )

<hamiltonian name="h0" type="generic" target="e">
   <pairpot type="coulomb" name="ElecElec" source="e" target="e"/>
   <pairpot type="coulomb" name="IonIon" source="ion0" target="ion0"/>
   <pairpot type="pseudo" name="PseudoPot" source="ion0" wavefunction="psi0" format="xml">
      <pseudo elementType="O" href="O.ccECP.xml" nrule="4"/>
      <pseudo elementType="V" href="V.ccECP.xml" nrule="6"/>
   </pairpot>
</hamiltonian>

A secondary, more expensive option applies the same rule to every atomic species via a single integer. This is not recommended unless a single simple convergence parameter is desired:

qmc = generate_qmcpack(
    ...,
    pseudos = ['V.ccECP.xml','O.ccECP.xml'],
    nrule   = 6,
    )

<hamiltonian name="h0" type="generic" target="e">
   <pairpot type="coulomb" name="ElecElec" source="e" target="e"/>
   <pairpot type="coulomb" name="IonIon" source="ion0" target="ion0"/>
   <pairpot type="pseudo" name="PseudoPot" source="ion0" wavefunction="psi0" format="xml">
      <pseudo elementType="O" href="O.ccECP.xml" nrule="6"/>
      <pseudo elementType="V" href="V.ccECP.xml" nrule="6"/>
   </pairpot>
</hamiltonian>