Information processing apparatus and information processing method

Patent metadata

Field	Value
Publication number	US-2021072959-A1
Application number	US-202017005900-A
Country	US
Kind code	A1
Filing date	Aug 28, 2020
Priority date	Sep 6, 2019
Publication date	Mar 11, 2021
Grant date	—

Abstract

An information processing apparatus includes an annealing control unit, a spin interaction memory, a random number generation unit, and a spin state update unit and obtains a solution by using an Ising model. The annealing control unit controls an annealing step and a parameter of a temperature and a parameter of a self-action. The spin interaction memory stores the interaction coefficient of a spin. The random number generation unit generates a predetermined random number. The spin state update unit includes a spin buffer that stores values of a plurality of spins, an instantaneous magnetic field calculation unit that calculates instantaneous magnetic fields of the plurality of spins, a probability calculation unit that calculates update probabilities of the plurality of spins, and a spin state determination unit that updates the values of the spins based on the update probabilities and a random number.

First claim

What is claimed is:

1 . An information processing apparatus comprising an annealing control unit, a spin interaction memory, a random number generation unit, and a spin state update unit and obtaining a solution by using an Ising model, wherein
the annealing control unit controls an annealing step and controls a parameter of a temperature and a parameter of self-action, the spin interaction memory stores an interaction coefficient of a spin, the random number generation unit generates a predetermined random number, and the spin state update unit includes
a spin buffer that stores values of a plurality of spins,
an instantaneous magnetic field calculation unit that calculates instantaneous magnetic fields of the plurality of spins;
a probability calculation unit that calculates update probabilities of the plurality of spins, and
a spin state determination unit that updates the values of the spins based on the update probabilities and the random number.

2 . The information processing apparatus according to claim 1 , wherein
the spin state update unit includes
a plurality of instantaneous magnetic field calculation units that calculate the instantaneous magnetic fields of the plurality of spins in parallel,
a plurality of probability calculation units that calculate the update probabilities of the plurality of spins in parallel, and
a plurality of spin state determination units that update the values of the plurality of spins in parallel based on the update probabilities and the random number.

3 . The information processing apparatus according to claim 2 , wherein
before an annealing step is started, the instantaneous magnetic fields are initialized based on the values of the spins, an external magnetic field coefficient, and the interaction coefficient, and the instantaneous magnetic field calculation unit updates the values of the instantaneous magnetic fields as the annealing step proceeds.

4 . The information processing apparatus according to claim 3 , wherein
the instantaneous magnetic field calculation unit includes an instantaneous magnetic field register that stores the values of the instantaneous magnetic fields, and when updating the values of the instantaneous magnetic fields as the annealing step proceeds, for spins changed in an immediately preceding annealing step, calculates updated instantaneous magnetic fields of the spins by using the values of the spins, an interaction coefficient for the spins, and the values of the instantaneous magnetic fields before an update stored in the instantaneous magnetic field register.

5 . The information processing apparatus according to claim 4 , further comprising:
an inverted spin buffer; and an inverted spin selection circuit, wherein as the annealing step proceeds, when updating the values of the spins, the spin state determination unit stores the values of updated spins and inversion flags for identifying the updated spins in the inversion spin buffer, the inversion spin selection circuit sends the values of the updated spins to the instantaneous magnetic field calculation unit and sends information for identifying the updated spins based on the inversion flags to the spin interaction memory, and the spin interaction memory sends an interaction coefficient related to the spins to the instantaneous magnetic field calculation unit based on the information for identifying the updated spins.

6 . The information processing apparatus according to claim 2 , wherein
the probability calculation unit compares a predetermined function and the predetermined random number and determines where to update the spins by inverting the spins based on the comparison result or to maintain states of the spins.

7 . The information processing apparatus according to claim 6 , wherein
the predetermined function is a function obtained by linearly approximating a sigmoid function.

8 . The information processing apparatus according to claim 6 , wherein
the annealing control unit controls a value of 2T as the parameter of the temperature and controls a value of qT as the parameter of the self-action, the random number generation unit generates a random number having a value between −2T and 2T, and the predetermined function has a value of a spin, an instantaneous magnetic field, and qT as arguments.

9 . The information processing apparatus according to claim 1 , wherein
the parameter of the self-action takes a maximum value in a final annealing step.

10 . The information processing apparatus according to claim 5 , wherein
in a predetermined annealing step, the inverted spin selection circuit sends the values of all the updated spins to the instantaneous magnetic field calculation unit and sends a step end signal to the annealing control unit when information for identifying all the spins updated based on the inversion flags is sent to the spin interaction memory, and upon receiving the step end signal, the annealing control unit advances the annealing step by 1 and updates the parameter of the temperature and the parameter of the self-action.

11 . The information processing apparatus according to claim 10 , further comprising:
a first spin interaction memory and a second spin interaction memory, as the spin interaction memory; and a first spin state update unit and a second spin state update unit, as the spin state update unit, wherein the first spin state update unit includes a first instantaneous magnetic field calculation unit, a first inverted spin buffer, and a first inverted spin selection circuit, the second spin state update unit includes a second instantaneous magnetic field calculation unit, a second inverted spin buffer, and a second inverted spin selection circuit, the first instantaneous magnetic field calculation unit receives interaction coefficients from the first spin interaction memory and the second spin interaction memory and receives values of spins from the first inverted spin buffer and the second inverted spin buffer, the second instantaneous magnetic field calculation unit receives interaction coefficients from the first spin interaction memory and the second spin interaction memory and receives values of spins from the first inverted spin buffer and the second inverted spin buffer, and upon receiving both a first step end signal from the first inverted spin selection circuit and a second step end signal from the second inverted spin selection circuit, the annealing control unit advances an annealing step by 1 and updates a parameter of temperature and a parameter of self-action.

12 . An information processing apparatus comprising:
a plurality of semiconductor chips that are mounted with the information processing apparatus according to claim 1 , wherein the plurality of semiconductor chips share the interaction coefficient in the spin interaction memory and the values of the spins.

13 . The information processing apparatus according to claim 1 , wherein
the plurality of spins are grouped and the spins in one group are unified to a value determined by a majority of the values of the spins of the group.

14 . An information processing method for obtaining a solution by using an Ising model by an information processing apparatus including an annealing control unit, a spin interaction memory, a random number generation unit, and a spin state update unit, wherein
the annealing control unit controls an annealing step and updates a parameter of a temperature and a parameter of a self-action, the spin interaction memory stores a spin interaction coefficient, the random number generation unit generates a pr

Assignees

• Hitachi Ltd
• Univ Hokkaido Nat Univ Corp

Inventors

• Mertig Normann
• Takemoto Takashi
• Takamaeda Shinya
• Yamamoto Kasho
• Motomura Masato
• Sakai Akira
• Teramoto Hiroshi

Classifications

• G06N7/01

  Probabilistic graphical models, e.g. probabilistic networks · CPC title

• G06F7/582 Primary

  Pseudo-random number generators · CPC title

• G06F7/588 Primary

  Random number generators, i.e. based on natural stochastic processes · CPC title

• G06N10/00

  Quantum computing, i.e. information processing based on quantum-mechanical phenomena · CPC title

• G06N7/005

  Physics · mapped topic