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Outputs

Purpose: Base output structure and common property definitions

Notes

One Outputs section holds the calculated properties of a single system configuration, identified through model_system_ref; on its own it describes a single-point calculation. WorkflowOutputs extends Outputs with a step index, for when that configuration is one point in an ordered sequence: a geometry optimization is then a series of WorkflowOutputs, each carrying the full Outputs content for its configuration and ordered by step.

These sections live under archive.data.outputs. This is distinct from the workflow graph archive.workflow2, which only references them through Links (workflow2.outputs) and summarizes them in workflow2.results; it does not hold the properties itself.

Within one Outputs section, the converged result and the SCF iteration history that produced it sit in separate subsections:

  • Outputs.total_energies (repeats=True) holds one or more TotalEnergy sections, each the converged total energy of the configuration. Energy components belong inside a TotalEnergy through its contributions subsections; these need not be exhaustive, so the total is not necessarily their sum. The schema currently defines neither an ordering nor a sequence meaning for the repeated entries.
  • Outputs.scf_steps (repeats=False) holds a single SCFSteps with the self-consistent iteration history for that same configuration. SCFSteps.energies_total is the ordered sequence of total energies across SCF iterations, converging to the configuration's total energy in TotalEnergy; SCFSteps.delta_energies_total holds the differences between consecutive values of that sequence.

Conceptual geometry-optimization layout:

WorkflowOutputs(step=0)                        # one configuration
    total_energies -> TotalEnergy              # converged total energy
    scf_steps      -> SCFSteps.energies_total  # SCF iteration history for it

WorkflowOutputs(step=1)
    total_energies -> TotalEnergy
    scf_steps      -> SCFSteps.energies_total

Relationship map

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classDiagram
    class AbsorptionSpectrum
    class ChemicalPotential
    class CrystalFieldSplitting
    class ElectronicBandGap
    class ElectronicBandStructure
    class ElectronicDensityOfStates
    class ElectronicEigenvalues
    class ElectronicGreensFunction
    class ElectronicSelfEnergy
    class FermiSurface
    class HoppingMatrix
    class HybridizationFunction
    class KineticEnergy
    class Occupancy
    class Outputs
    class Permittivity
    class PhysicalProperty
    class PotentialEnergy
    class QuasiparticleWeight
    class RadiusOfGyration
    class SCFSteps
    class Temperature
    class TotalEnergy
    class TotalForce
    class XASSpectrum
    Outputs *-- AbsorptionSpectrum : absorption_spectra
    Outputs *-- ChemicalPotential : chemical_potentials
    Outputs *-- CrystalFieldSplitting : crystal_field_splittings
    Outputs *-- ElectronicBandGap : electronic_band_gaps
    Outputs *-- ElectronicBandStructure : electronic_band_structures
    Outputs *-- ElectronicDensityOfStates : electronic_dos
    Outputs *-- ElectronicEigenvalues : electronic_eigenvalues
    Outputs *-- ElectronicGreensFunction : electronic_greens_functions
    Outputs *-- ElectronicSelfEnergy : electronic_self_energies
    Outputs *-- FermiSurface : fermi_surfaces
    Outputs *-- HoppingMatrix : hopping_matrices
    Outputs *-- HybridizationFunction : hybridization_functions
    Outputs *-- KineticEnergy : kinetic_energies
    Outputs *-- Occupancy : occupancies
    Outputs *-- Permittivity : permittivities
    Outputs *-- PotentialEnergy : potential_energies
    Outputs *-- QuasiparticleWeight : quasiparticle_weights
    Outputs *-- RadiusOfGyration : radii_of_gyration
    Outputs *-- SCFSteps : scf_steps
    Outputs *-- Temperature : temperatures
    Outputs *-- TotalEnergy : total_energies
    Outputs *-- TotalForce : total_forces
    Outputs *-- XASSpectrum : xas_spectra

Legend

composition (has-a)

Quantities by Key Sections

Outputs

Section Description MetaInfo
Outputs Output properties of a simulation. Open in MetaInfo browser
Quantity Type Description
model_system_ref Reference Reference to the ModelSystem section in which the output physical properties were calculated.
model_method_ref Reference Reference to the ModelMethod section containing the details of the mathematical model with which the output physical properties were calculated.

SCFSteps

Section Description MetaInfo
SCFSteps Data recorded at each step of a self-consistent DFT calculation. Open in MetaInfo browser
Quantity Type Description
energies_total m_float64(float) (shape: ['*']) Ordered sequence of total energies from the SCF iterations within one system configuration.
delta_energies_total m_float64(float) (shape: ['*'])
Absolute change of total energy between consecutive SCF steps.Absolute change of total energy between consecutive SCF steps. When
derived from energies_total, the values follow
\(\Delta E_i = \lvert E_{i+1} - E_i \rvert\), so N SCF energies
produce N - 1 energy deltas.
energy_error_estimate m_float64(float) (shape: ['*'])
Estimate of the remaining error in the total energy at each SCF step,Estimate of the remaining error in the total energy at each SCF step,
derived from the density residual rather than from the change of the
total energy itself. For example, Quantum ESPRESSO's "estimated scf
accuracy" is the Hartree self-energy of the density residual. Distinct
from delta_energies_total, which is the change of the total energy
between consecutive steps.
delta_potential_rms m_float64(float) (shape: ['*']) Root mean square of change of potential energy at each SCF step.
delta_charge_abs m_float64(float) (shape: ['*'])
Volume-integrated absolute change of the electron density betweenVolume-integrated absolute change of the electron density between
consecutive SCF steps, integral \|rho_n(r) - rho_(n-1)(r)\| d^3r,
expressed as a charge (equivalently a number of electrons). Reported by
all-electron codes such as WIEN2k (:DIS). The exact norm and any
normalization are a code-reported convention that the schema does not
enforce.
delta_charge_density_rms m_float64(float) (shape: ['*'])
Root mean square, over real-space grid points, of the change of theRoot mean square, over real-space grid points, of the change of the
electron density between consecutive SCF steps. Unlike delta_charge_abs
the volume is retained, so this is a charge density. Reported by
plane-wave codes such as VASP (rms(c)).
delta_charge_relative m_float64(float) (shape: ['*']) Integrated absolute density change normalized by the electron count, integral \|rho_n - rho_(n-1)\| d^3r / N, hence dimensionless. Reported by exciting ("charge distance") and GPAW (per valence electron).
delta_density_matrix_rms m_float64(float) (shape: ['*'])
Root mean square of the change of the density-matrix elements P_munuRoot mean square of the change of the density-matrix elements P_munu
(in the non-orthonormal atomic-orbital basis) between consecutive SCF
steps. The elements are dimensionless, so is this residual. Reported by
Gaussian-basis codes such as CRYSTAL (tst) and ORCA (RMS-DP).
delta_density_matrix_max m_float64(float) (shape: ['*'])
Maximum absolute change of the density-matrix elements P_munu betweenMaximum absolute change of the density-matrix elements P_munu between
consecutive SCF steps; the max-norm counterpart of
delta_density_matrix_rms. Reported by Gaussian-basis codes such as
CP2K, CRYSTAL (PX), and ORCA (Max-DP).
delta_wavefunction_rms m_float64(float) (shape: ['*']) Root mean square of change of wavefunction coefficients at each SCF step. Dimensionless quantity representing convergence of orbital coefficients.
delta_force_abs m_float64(float) (shape: ['*']) Absolute change of forces at each SCF step.
durations m_float64(float) (shape: ['*']) Time spent at each SCF step.
code_specific_quantities JSON Code specific quantities that are recorded during SCF convergence.

PhysicalProperty

Section Description MetaInfo
PhysicalProperty A base section for computational output properties, containing all relevant (meta)data. Open in MetaInfo browser
Quantity Type Description
name m_str(str) Name of the physical property. Example: 'ElectronicBandGap'.
iri URL Internationalized Resource Identifier (IRI) pointing to a definition, typically within a larger, ontological framework.
type m_str(str) Type categorization of the physical property. Example: an ElectronicBandGap can be 'direct' or 'indirect'.
contribution_type m_str(str) Type of contribution to the physical property. Hence, only applies to contributions instances. Example: TotalEnergy may have contributions like kinetic, potential, etc.
label m_str(str) Label for additional classification of the physical property. Example: an ElectronicBandGap can be labeled as 'DFT' or 'GW' depending on the methodology used to calculate it.
entity_ref Reference
Reference to the entity that the physical property refers to.Reference to the entity that the physical property refers to. Examples:
- a simulated physical property may refer to the macroscopic system as a whole. In that case,
outputs.model_system_ref (see outputs.py) points to the ModelSystem section.
- a simulated physical property may instead refer to a specific entity within that system, such as
an AtomsState, a CGBeadState, another ParticleState subclass, or an
ElectronicState, via entity_ref.
is_derived m_bool(bool)
Flag indicating whether the physical property is derived from other physical properties.Flag indicating whether the physical property is derived from other physical properties. We make
the distinction between directly parsed and derived physical properties:
- Directly parsed: the physical property is directly parsed from the simulation output files.
- Derived: the physical property is derived from other physical properties. No extra numerical settings
are required to calculate the physical property.
physical_property_ref Reference Reference to the PhysicalProperty section from which the physical property was derived. If physical_property_ref is populated, the quantity is_derived is set to True via normalization.
is_converged m_bool(bool) Flag indicating whether the calculation that yields this physical property is converged or not after a SCF or optimization process. This information is obtained from the workflow section.