# -*- coding: utf-8 -*-
"""The energy and Hessian of a structure from the flowchart's Model Chemistry.
A thin mixin over :class:`seamm_exec.hessian.HessianDriver`, which holds the
route choice (warm MDI engine or tasks; analytic or finite differences), the
engine's environment and cores, and the optimization over the engine. The
driver moved to seamm_exec on 2026-11-05 so that the Thermochemistry, Normal
Mode Sampling and Vibrational Analysis steps share one copy.
"""
import logging
import seamm_util.printing as printing
# The helpers moved with the driver; imported here for older callers.
from seamm_exec.hessian import ( # noqa: F401
HessianDriver,
_accepts_keyword,
module_environment,
modules_to_load,
parse_cpu_ids,
physical_cores_allowed,
slurm_allocated_cpus,
)
logger = logging.getLogger(__name__)
printer = printing.getPrinter("Thermochemistry")
[docs]
class ModelChemistryHessian:
"""Mixin: the energy and Cartesian Hessian from the Model Chemistry.
The route is the step's ``_hessian_route`` ("automatic", "warm engine over
MDI" or "separate tasks"); the engine's settings fingerprints from the last
calculation are in ``_fingerprints``.
"""
[docs]
def model_chemistry(self):
"""The ``_model_chemistry`` wrapper: a preset's own (see the CBH
approach's presets), else the one published upstream, or None."""
preset = getattr(self, "_preset_mc", None)
if preset is not None:
return preset
if not self.variable_exists("_model_chemistry"):
return None
return self.get_variable("_model_chemistry")
def _hessian_driver(self):
return HessianDriver(
self,
self.model_chemistry(),
route=getattr(self, "_hessian_route", "automatic") or "automatic",
who="Thermochemistry",
hint="or put the calculation in this step's subflowchart",
print_to=printer,
)
[docs]
def model_chemistry_energy(self, configuration):
"""The energy (kJ/mol) of the configuration with the Model Chemistry."""
return self._hessian_driver().energy(configuration)
[docs]
def energy_and_hessian(self, configuration, delta_bohr=0.01):
"""The energy (kJ/mol), the Cartesian Hessian (hartree/bohr², (3N, 3N))
and how it was obtained: "analytic", "finite differences over MDI" or
"finite differences as tasks"."""
return self.optimize_and_hessian(configuration, delta_bohr, optimize=False)
[docs]
def optimize_and_energy(
self, configuration, optimize=True, fmax=0.005, max_steps=200
):
"""Optionally optimize the structure over the warm engine, then its
energy (kJ/mol). With no engine (tasks) the energy only."""
driver = self._hessian_driver()
try:
return driver.optimize_and_energy(configuration, optimize, fmax, max_steps)
finally:
self._fingerprints = driver.fingerprints
self._last_optimization = getattr(driver, "last_optimization", None)
[docs]
def optimize_and_hessian(
self, configuration, delta_bohr=0.01, optimize=True, fmax=0.005, max_steps=200
):
"""Optionally optimize the structure (ASE BFGS over the warm engine),
then the energy and Hessian, in one engine session.
Returns
-------
(float, numpy.ndarray, str)
As `energy_and_hessian`.
"""
driver = self._hessian_driver()
try:
return driver.optimize_and_hessian(
configuration, delta_bohr, optimize, fmax, max_steps
)
finally:
self._fingerprints = driver.fingerprints
self._last_optimization = getattr(driver, "last_optimization", None)
