Single-Point Calculation¶

The standard BaseCalculator.calculate() method evaluates a backend's available properties for a structure exactly as given, with no optimization step. MEGNetCalculator instead returns only formation_energy, while the minimal RandomCalculator test stub returns only energy and forces and omits final_structure.

Basic Usage¶

from ase.build import bulk
from materialsframework.calculators import M3GNetCalculator

struct = bulk("Fe", "bcc", a=2.87, cubic=True)
calc = M3GNetCalculator()
res = calc.calculate(struct)

print(res["final_structure"])
print(res["energy"])
print(res["forces"])
print(res["stress"])

calculate() vs. relax()¶

calculate() runs a single evaluation of the underlying ASE Calculator: no FrechetCellFilter, no FixSymmetry/FixAtoms constraints, no optimizer loop, no trajectory. Use it when the input structure is already at the geometry you want evaluated, such as scoring an externally generated configuration or comparing an MLIP's energy against a DFT-relaxed reference. Use relax() when the structure still needs to reach mechanical equilibrium.

	`calculate()`	`relax()`
Optimization	None	Runs to `fmax`/`steps` convergence
Cell relaxation	N/A	Optional via `relax_cell`
Returned `final_structure`	Same as input	Relaxed structure
`trajectory` key	Not present	`TrajectoryObserver` with intermediate frames

Output Dictionary¶

Key	Description
`final_structure`	Input structure as pymatgen `Structure`, unchanged
Property keys from `AVAILABLE_PROPERTIES`	e.g. `energy`, `forces`, `stress`, populated from the calculator

Input Formats¶

Both pymatgen Structure and ASE Atoms objects are accepted:

from pymatgen.core import Structure

# From pymatgen Structure
pmg_struct = Structure(...)
res = calc.calculate(pmg_struct)

# From ASE Atoms
from ase.build import bulk
ase_atoms = bulk("Cu", "fcc", a=3.6)
res = calc.calculate(ase_atoms)