Outputs

ProgramOutput is the core object that captures a QC program execution, including the exact input, the structured output payload at .results, logs, traceback information for failures, and ExecutionInfo at .execution. Producer identity belongs to .results.provenance.

qcdata.ProgramOutput

The core output object from a quantum chemistry calculation.

Attributes:

Name	Type	Description
input_data	InputType	The input data for the calculation. Any of qcdata.Inputs.
success	Literal[True, False]	Whether the calculation was successful.
results	DataType	Scientific data returned by the calculation, including output files. Any of qcdata.Data.
logs	str | None	The logs from the calculation.
traceback	str | None	The traceback from the calculation, if it failed.
execution	ExecutionInfo	Runtime information; defaults to an empty ExecutionInfo.
extras	Dict[str, Any]	Additional information to bundle with the results. Use for schema development and scratch space.
plogs	str	@property Print the logs.
ptraceback	str	@property Print the traceback.

data property

data: DataType

Deprecated access to results.

plogs property

plogs: None

Print the logs.

ptraceback property

ptraceback: None

Print the traceback.

options: members: false

Canonical results field

Scientific models retain their Data names and can exist independently of an execution. Within ProgramOutput, that data is the calculation's results: use output.results.energy, output.results.gradient, or output.results.final_structure.

Serialization always emits "results", never "data". The sole deprecated API is .data, which returns the same object as .results with a FutureWarning. Constructor arguments and serialized payloads containing "data" are accepted with the same warning and migrated to "results". Providing both names raises ValueError during validation. The rename leaves the caller's original field names unchanged. This compatibility layer is scheduled for removal in the major release following this one.

The old Results and *Results classes, qcdata.models.results module, qcio import shim, stdout/files forwarding, and deprecated convenience helpers have been removed. Use ProgramOutput, *Data, logs, results.files, and explicit scientific attributes instead.

Input and result contract

The result type depends on the input, regardless of success or failure:

Input	Result type
FileInput	FileData only
Energy, gradient, Hessian ProgramInput	SinglePointData
Optimization or transition-state ProgramInput	OptimizationData
Conformer-search ProgramInput	ConformerSearchData
Scan ProgramInput	ScanData

Successful single-point calculations require the requested value; successful optimizations and scans require a nonempty trajectory, and successful conformer searches require conformers. Failed calculations require a traceback and retain the corresponding scientific type, with empty or partial values allowed. Producer provenance is always required.

When deserializing, ProgramOutput uses the input contract to select the result model. Empty scientific payloads therefore retain their type when saved and reopened, including inside trajectories. No additional serialized type tag is needed. Explicit generic types must agree with the input contract.

input_data belongs on ProgramOutput, not inside results. Save the whole output when you need scientific values together with the requested calculation and execution context. Save a standalone data object when exchanging only scientific values and producer identity.

Migrating existing outputs

This is a breaking schema change with no automatic legacy-provenance loader:

• Move provenance.program, provenance.program_version, and provenance.extras into results.provenance.
• Move scratch_dir, wall_time, and hostname into execution; rename hostcpus to host_cpu and hostmem to host_mem_gib. Memory accepts fractional GiB. These renames have no compatibility aliases.
• Remove the old top-level provenance field.
• Use FileData(provenance=...) only with FileInput. For failed structured calculations, construct the corresponding scientific type, such as SinglePointData(provenance=...), and update generic annotations accordingly.
• Apply the same migration to each nested trajectory output. Do not copy parent provenance or execution information to children.

Standalone structured data now also requires explicit provenance. QCSchema conversion preserves source extras and additional provenance metadata without inventing a QCEngine attribution. QCSchema conversion obtains it from provenance.creator and provenance.version and raises ValueError if producer identity is missing.

External callers must migrate too: qccodec should attach the parsed producer and version to the returned data; qccompute should supply execution and return the corresponding scientific data type even when a structured calculation fails without producing values.

Reconstructed trajectory records

Parsers may reconstruct trajectory entries from the parent calculation and saved structures and energies. Such entries describe recovered scientific evaluations, which need not be separate process invocations. An energy-only snapshot has calctype="energy"; a snapshot with a recovered gradient may use "gradient". Every successful entry still satisfies the requested-value contract. Missing an optional gradient artifact does not by itself establish execution failure.