An AiiDA plugin for the Python-based Simulations of Chemistry Framework (PySCF).
The recommended method of installation is through pip
:
pip install aiida-pyscf
To use aiida-pyscf
a configured AiiDA profile is required. Please refer to the
documentation of aiida-core
for
detailed instructions.
To run a PySCF calculation through AiiDA using the aiida-pyscf
plugin, the computer needs to be configured where PySCF
should be run. Please refer to the
documentation of aiida-core
for detailed instructions.
Then the PySCF code needs to be configured. The following YAML configuration file can be taken as a starting point:
label: pyscf
description: PySCF
computer: localhost
filepath_executable: python
default_calc_job_plugin: pyscf.base
use_double_quotes: false
with_mpi: false
prepend_text: ''
append_text: ''
Write the contents to a file named pyscf.yml
, making sure to update the value of computer
to the label of the
computer configured in the previous step. To configure the code, execute:
verdi code create core.code.installed --config pyscf.yml -n
This should now have created the code with the label pyscf
that will be used in the following examples.
The default calculation is to perform a mean-field calculation. At a very minimum, the structure and the mean-field method should be defined:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('H2O'))
builder.parameters = Dict({'mean_field': {'method': 'RHF'}})
results, node = run.get_node(builder)
This runs a Hartree-Fock calculation on the geometry of a water molecule.
The main results are stored in the parameters
output, which by default contain the computed total_energy
and
forces
, details on the molecular orbitals, as well as some timing information:
print(results['parameters'].get_dict())
{
'mean_field': {
'forces': [
[-6.4898366104394e-16, 3.0329042995656e-15, 2.2269765466236],
[1.122487932593e-14, 0.64803103141326, -1.1134882733107],
[-1.0575895664886e-14, -0.64803103141331, -1.1134882733108]
],
'forces_units': 'eV/Å',
'molecular_orbitals': {
'labels': [
'0 O 1s',
'0 O 2s',
'0 O 2px',
'0 O 2py',
'0 O 2pz',
'1 H 1s',
'2 H 1s'
],
'energies': [
-550.86280025028,
-34.375426862456,
-16.629598134599,
-12.323304634736,
-10.637428057751,
16.200273277782,
19.796075801491
],
'occupations': [2.0, 2.0, 2.0, 2.0, 2.0, 0.0, 0.0]
},
'total_energy': -2039.8853743664,
'total_energy_units': 'eV',
},
'timings': {
'total': 1.3238215579768, 'mean_field': 0.47364449803717
},
}
The geometry of the structure is fully defined through the structure
input, which is provided by a StructureData
node. Any other properties, e.g., the charge and what basis set to use, can be specified through the structure
dictionary in the parameters
input:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('H2O'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'structure': {
'basis ': 'sto-3g',
'charge': 0,
}
})
results, node = run.get_node(builder)
Any attribute of the pyscf.gto.Mole
class which is used to define the structure can
be set through the structure
dictionary, with the exception of the atom
and unit
attributes, which are set
automatically by the plugin based on the StructureData
input.
The geometry can be optimized by specifying the optimizer
dictionary in the input parameters
. The solver
has to be
specified, and currently the solvers geometric
and berny
are supported. The convergence_parameters
accepts the
parameters for the selected solver (see
PySCF documentation for details):
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('H2O'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'optimizer': {
'solver': 'geometric',
'convergence_parameters': {
'convergence_energy': 1e-6, # Eh
'convergence_grms': 3e-4, # Eh/Bohr
'convergence_gmax': 4.5e-4, # Eh/Bohr
'convergence_drms': 1.2e-3, # Angstrom
'convergence_dmax': 1.8e-3, # Angstrom
}
}
})
results, node = run.get_node(builder)
The optimized structure is returned in the form of a StructureData
under the structure
output label. The structure
and energy of each frame in the geometry optimization trajectory, are stored in the form of a TrajectoryData
under the
trajectory
output label. The total energies can be retrieved as follows:
results['trajectory'].get_array('energies')
To compute localized orbitals, specify the desired method in the parameters.localize_orbitals.method
input:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('H2O'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'localize_orbitals': {'method': 'ibo'}
})
results, node = run.get_node(builder)
The following methods are supported: boys
, cholesky
, edmiston
, iao
, ibo
, lowdin
, nao
, orth
, pipek
,
vvo
. For more information, please refer to the PySCF documentation.
In order to compute the Hessian, specify an empty dictionary for the hessian
key in the parameters
input:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('H2O'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'hessian': {}
})
results, node = run.get_node(builder)
The computed Hessian will be attached as an ArrayData
node with the link label hessian
. Use
node.outputs.hessian.get_array('hessian')
to retrieve the computed Hessian as a numpy array for further processing.
To instruct the calculation to dump a representation of the Hamiltonian to FCIDUMP files, add the fcidump
dictionary
to the parameters
input:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('N2'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'fcidump': {
'active_spaces': [[5, 6, 8, 9]],
'occupations': [[1, 1, 1, 1]]
}
})
results, node = run.get_node(builder)
The active_spaces
and occupations
keys are requires and each take a list of list of integers. For each element in
the list, a FCIDUMP file is generated for the corresponding active spaces and the occupations of the orbitals. The shape
of the active_spaces
and occupations
array has to be identical.
The generated FCIDUMP files are attached as SinglefileData
output nodes in the fcidump
namespace, where the label is
determined by the index of the corresponding active space in the list:
print(results['fcidump']['active_space_0'].get_content())
&FCI NORB= 4,NELEC= 4,MS2=0,
ORBSYM=1,1,1,1,
ISYM=1,
&END
0.5832127121682998 1 1 1 1
0.5359642500498074 1 1 2 2
-2.942091015256668e-15 1 1 3 2
0.5381290185905914 1 1 3 3
-3.782672959584676e-15 1 1 4 1
...
The pyscf.tools.cubegen
module provides functions to compute various properties of the system and write them as CUBE
files. The PyscfCalculation
plugin currently supports computing the following:
- molecular orbitals
- charge density
- molecular electrostatic potential
To instruct the calculation to dump a representation of any of these quantities to CUBE files, add the cubegen
dictionary to the parameters
input:
from ase.build import molecule
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code
builder = load_code('pyscf').get_builder()
builder.structure = StructureData(ase=molecule('N2'))
builder.parameters = Dict({
'mean_field': {'method': 'RHF'},
'cubegen': {
'orbitals: {
'indices': [5, 6],
'parameters': {
'nx': 40,
'ny': 40,
'nz': 40,
}
},
'density': {
'parameters': {
'resolution': 300,
}
},
'mep': {
'parameters': {
'resolution': 300,
}
}
}
})
results, node = run.get_node(builder)
The indices
key has to be specified for the orbitals
subdictionary and takes a list of integers, indicating the
indices of the molecular orbitals that should be written to file. Additional parameters can be provided in the
parameters
subdictionary (see the
PySCF documentation
for details). The parameters
subdictionaries for the density
and mep
dictionaries are optional. To compute the
charge density and molecular electrostatic potential, the and empty dictionary for the density
and mep
keys,
respectively, is sufficient.
The generated CUBE files are attached as SinglefileData
output nodes in the cubegen
namespace, with the orbitals
,
density
and mep
subnamespaces. For the orbitals
subnamespace, the label is determined by the corresponding
molecular orbital index:
print(results['cubegen']['orbitals']['mo_5'].get_content())
Orbital value in real space (1/Bohr^3)
PySCF Version: 2.1.1 Date: Sun Apr 2 15:59:19 2023
2 -3.000000 -3.000000 -4.067676
40 0.153846 0.000000 0.000000
40 0.000000 0.153846 0.000000
40 0.000000 0.000000 0.208599
7 0.000000 0.000000 0.000000 1.067676
7 0.000000 0.000000 0.000000 -1.067676
-1.10860E-04 -1.56874E-04 -2.16660E-04 -2.92099E-04 -3.84499E-04 -4.94299E-04
-6.20809E-04 -7.62048E-04 -9.14724E-04 -1.07439E-03 -1.23579E-03 -1.39331E-03
...
Warning PySCF is known to fail when computing the MEP with DHF, DKS, GHF and GKS references.
The plugin will automatically instruct PySCF to write a checkpoint file. If the calculation did not converge, it will
finish with exit status 410
and the checkpoint file is attached as a SinglefileData
as the checkpoint
output node.
This node can then be passed as input to a new calculation to restart from the checkpoint:
failed_calculation = load_node(IDENTIFIER)
builder = failed_calculation.get_builder_restart()
builder.checkpoint = failed_calculation.outputs.checkpoint
submit(builder)
The plugin will write the checkpoint file of the failed calculation to the working directory such that PySCF can start of from there.
The PyscfCalculation
plugin does not support all PySCF functionality; it aims to support most functionality that is
computationally intensive, as in this case it is important to be able to offload these calculations as a calcjob on a
remote compute resource. Most post-processing utilities are computationally inexpensive, and since the API is in Python,
they can be called directly in AiiDA workflows as calcfunction
s. Many PySCF utilities require the model of the
system as an argument, where model is the main object used in PySCF, i.e. the object assigned to the mean_field
variable in the following:
from pyscf import scf
mean_field = scf.RHF(..)
mean_field.kernel()
The kernel
method is often computationally expensive, but its results (stored on the model object) are lost when the
PyscfCalculation
finishes as the Python interpreter of the calcjob shuts down and so the mean_field
object no longer
exists. This would force post-processing code to reconstruct the model from scratch and rerun the expensive kernel.
Therefore, the PyscfCalculation
serializes the PySCF model that was computed and stores it as a PickledData
output
node with the link label model
in the provenance graph. This allows recreating the model in another Python interpreter
and have it ready to be used for post-processing:
from pyscf.hessian import thermo
node = load_node() # Load the completed `PyscfCalculation`
mean_field = node.outputs.model.load() # Reconstruct the model by calling the `load()` method
hessian = mean_field.Hessian().kernel()
freq_info = thermo.harmonic_analysis(mean_field.mol, hessian)
There are a variety of reasons why a PySCF calculation may not finish with the intended result. Examples are the
self-consistent field cycle not converging or the job getting killed by the scheduler because it ran out of the
requested walltime. The PyscfBaseWorkChain
is designed to try and automatically recover from these kinds of errors
whenever it can potentially be handled. It is a simple wrapper around the PyscfCalculation
plugin that automatically
restarts a new PyscfCalculation
if the previous iterations failed. Launching a PyscfBaseWorkChain
is almost
identical to launching a PyscfCalculation
directly; the inputs just have to be "nested" inside the pyscf
namespace:
from aiida.engine import run
from aiida.orm import Dict, StructureData, load_code, load_node
from aiida_pyscf.workflows.base import PyscfBaseWorkChain
from ase.build import molecule
builder = PyscfBaseWorkChain.get_builder()
builder.pyscf.code = load_code('pyscf')
builder.pyscf.structure = StructureData(ase=molecule('H2O'))
builder.pyscf.parameters = Dict({
'mean_field': {
'method': 'RHF',
'max_cycle': 3,
}
})
results, node = run.get_node(builder)
In this example, we purposefully set the maximum number of iterations in the self-consistent field cycle to 3
('mean_field.max_cycle' = 3
), which will cause the first iteration to fail to reach convergence. The
PyscfBaseWorkChain
detects the error, indicated by exit status 410
on the PyscfCalculation
, and automatically
restarts the calculation from the saved checkpoint. After three iterations, the calculation converges:
$ verdi process status IDENTIFIER
PyscfBaseWorkChain<30126> Finished [0] [2:results]
├── PyscfCalculation<30127> Finished [410]
├── PyscfCalculation<30132> Finished [410]
└── PyscfCalculation<30137> Finished [0]
The following error modes are currently handled by the PyscfBaseWorkChain
:
120
: Out of walltime: The calculation will be restarted from the last checkpoint if available, otherwise the work chain is aborted140
: Node failure: The calculation will be restarted from the last checkpoint410
: Electronic convergence not achieved: The calculation will be restarted from the last checkpoint500
: Ionic convergence not achieved: The geometry optmizization did not converge, calculation will be restarted from the last checkpoint and structure
The main objective of a PyscfCalculation
is to solve the mean-field problem for a given structure. The results of
this, often computationally expensive, step are stored in the mean_field_run
variable in the main script:
mean_field = scf.RHF(structure)
density_matrix = mean_field.from_chk('restart.chk')
mean_field_run = mean_field.run(density_matrix)
The mean_field_run
object can be used for a number of further post-processing operations implemented in PySCF. To keep
the PyscfCalculation
interface simple, not all of this functionality is supported. However, as soon as the calculation
job finishes, the mean_field_run
variable is lost and can no longer be accessed to be used for further processing.
As a workaround, the PyscfCalculation
will "pickle" the
mean_field_run
object and attach it as the model
output to the calculation. The model
output node can be
"unpickled" to restore the original mean_field_run
object such that it can be used for further processing:
from aiida.engine import run
inputs = {}
results, node = run.get_node(PyscfCalculation, **inputs)
mean_field = node.outputs.model.load()
print(mean_field.e_tot)
Warning For certain cases, the calculation may fail to pickle the model and will except. In this case, one can set the
pickle_model
input to thePyscfCalculation
toFalse
.
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