Material generation apparatus and material generation method
AssigneeHitachi, Ltd.
InventorsTadayuki Matsumura, Yusuke Asari
Life of this patent
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Abstract
A genetic algorithm controller that controls respective processes using a genetic algorithm is configured. The processes include generation of a crystal structure of an inorganic material, a mutation operation of a crystal structure, a crossing-over operation of a crystal structure, structural relaxation calculation of a crystal structure, calculation of a predictive value of an objective function, selection and weeding out of a crystal structure based on a predictive value of an objective function, observation of an objective function value of a crystal structure by first-principle calculation, update of a regression model based on a result of observing the objective function value, and end determination for a material generation process.
Claims12
A material generation apparatus comprising:
- a genetic algorithm controller that controls respective processes using a genetic algorithm, the processes including generation of a crystal structure of an inorganic material, a mutation operation of a crystal structure, a crossing-over operation of a crystal structure, structural relaxation calculation of a crystal structure, calculation of a predictive value of an objective function, selection and weeding out of a crystal structure based on a predictive value of an objective function, observation of an objective function value of a crystal structure by first-principle calculation, update of a regression model based on a result of observing the objective function value, and end determination for a material generation process;
- and
- a neighborhood set generator that includes
- a mutation unit that generates an N-fold crystal structure of a crystal structure, and adds an atom of a randomly selected element to coordinates at which a distance to a nearest neighbor atom is largest,
- a mutation unit that generates an N-fold crystal structure of a crystal structure, and deletes an atom of which a distance to a nearest neighbor atom is smallest, and
- a crossing-over unit that selects two crystal structures, divides each of the crystal structures by a section determined by random numbers, and combines the two crystal structures by one internal coordinate expression.
A material generation method comprising:
- generating a current generation crystal structure set of an inorganic material by user definition or random generation at a time of start according to control of a genetic algorithm;
- generating a crystal structure of a new neighborhood set by a mutation operation of a crystal structure and a crossing-over operation of a crystal structure from the current generation crystal structure set;
- performing structural relaxation calculation on each crystal structure of the neighborhood set;
- calculating a feature amount with respect to each crystal structure after the structural relaxation calculation;
- calculating a predictive value of an objective function by inputting the calculated feature amount to a regression model;
- performing selection and weeding out of a crystal structure based on the predictive value of the objective function;
- repeating a loop from the generating of the crystal structure of the neighborhood set to the performing of the selection and weeding out of the crystal structure predetermined number of times;
- observing an objective function value by first-principle calculation or with reference to experimental data with respect to a crystal structure set;
- updating a regression model based on a result of observing the objective function value;
- and
- determining whether to end or continue processing by determining whether the result of observing the objective function value satisfies a predetermined condition.
Dependencies are inferred from the claim text.