mirror of
https://github.com/smyalygames/FiniteVolumeGPU.git
synced 2025-05-18 14:34:13 +02:00
274 lines
9.8 KiB
Python
274 lines
9.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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This python module implements MPI simulator class
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Copyright (C) 2018 SINTEF Digital
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""
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import logging
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from GPUSimulators import Simulator
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import numpy as np
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from mpi4py import MPI
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class MPISimulator(Simulator.BaseSimulator):
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def __init__(self, sim, comm):
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self.logger = logging.getLogger(__name__)
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autotuner = sim.context.autotuner
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sim.context.autotuner = None;
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super().__init__(sim.context,
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sim.nx, sim.ny,
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sim.dx, sim.dy,
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sim.cfl_scale,
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sim.num_substeps,
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sim.block_size[0], sim.block_size[1])
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sim.context.autotuner = autotuner
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self.sim = sim
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self.comm = comm
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self.rank = comm.rank
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#Get global dimensions
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self.grid = MPISimulator.getFactors(self.comm.size, 2)
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#Get neighbor node ids
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self.east = self.getEast()
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self.west = self.getWest()
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self.north = self.getNorth()
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self.south = self.getSouth()
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#Get local dimensions
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self.gc_x = int(self.sim.u0[0].x_halo)
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self.gc_y = int(self.sim.u0[0].y_halo)
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self.nx = int(self.sim.nx)
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self.ny = int(self.sim.ny)
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self.nvars = len(self.sim.u0.gpu_variables)
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#Allocate data for receiving
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#Note that east and west also transfer ghost cells
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#whilst north/south only transfer internal cells
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self.in_e = np.empty((self.nvars, self.ny + 2*self.gc_y, self.gc_x), dtype=np.float32)
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self.in_w = np.empty((self.nvars, self.ny + 2*self.gc_y, self.gc_x), dtype=np.float32)
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self.in_n = np.empty((self.nvars, self.gc_y, self.nx), dtype=np.float32)
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self.in_s = np.empty((self.nvars, self.gc_y, self.nx), dtype=np.float32)
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#Allocate data for sending
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self.out_e = np.empty_like(self.in_e)
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self.out_w = np.empty_like(self.in_w)
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self.out_n = np.empty_like(self.in_n)
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self.out_s = np.empty_like(self.in_s)
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#Set regions for ghost cells to read from
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self.read_e = np.array([ self.nx, 0, self.gc_x, self.ny + 2*self.gc_y])
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self.read_w = np.array([self.gc_x, 0, self.gc_x, self.ny + 2*self.gc_y])
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self.read_n = np.array([self.gc_x, self.ny, self.nx, self.gc_y])
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self.read_s = np.array([self.gc_x, self.gc_y, self.nx, self.gc_y])
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#Set regions for ghost cells to write to
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self.write_e = self.read_e + np.array([self.gc_x, 0, 0, 0])
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self.write_w = self.read_w - np.array([self.gc_x, 0, 0, 0])
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self.write_n = self.read_n + np.array([0, self.gc_y, 0, 0])
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self.write_s = self.read_s - np.array([0, self.gc_y, 0, 0])
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self.logger.debug("Simlator rank {:d} created ".format(self.rank))
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def substep(self, dt, step_number):
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self.exchange()
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self.sim.substep(dt, step_number)
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def download(self):
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return self.sim.download()
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def synchronize(self):
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self.sim.synchronize()
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def check(self):
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return self.sim.check()
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def computeDt(self):
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local_dt = np.array([np.float32(self.sim.computeDt())]);
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global_dt = np.empty(1, dtype=np.float32)
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self.comm.Allreduce(local_dt, global_dt, op=MPI.MIN)
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self.logger.debug("Local dt: {:f}, global dt: {:f}".format(local_dt[0], global_dt[0]))
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return global_dt[0]
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def exchange(self):
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#Shorthands for dimensions
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gc_x = self.gc_x
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gc_y = self.gc_y
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nx = self.nx
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ny = self.ny
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####
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# First transfer internal cells north-south
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####
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#Download from the GPU
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for k in range(self.nvars):
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self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_n[k,:,:], async=True, extent=self.read_n)
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self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_s[k,:,:], async=True, extent=self.read_s)
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self.sim.stream.synchronize()
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#Send to north/south neighbours
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comm_send = []
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comm_send += [self.comm.Isend(self.out_n, dest=self.north, tag=4*self.nt + 0)]
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comm_send += [self.comm.Isend(self.out_s, dest=self.south, tag=4*self.nt + 1)]
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#Receive from north/south neighbors
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comm_recv = []
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comm_recv += [self.comm.Irecv(self.in_s, source=self.south, tag=4*self.nt + 0)]
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comm_recv += [self.comm.Irecv(self.in_n, source=self.north, tag=4*self.nt + 1)]
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#Wait for incoming transfers to complete
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for comm in comm_recv:
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comm.wait()
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#Upload to the GPU
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for k in range(self.nvars):
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self.sim.u0[k].upload(self.sim.stream, self.in_n[k,:,:], extent=self.write_n)
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self.sim.u0[k].upload(self.sim.stream, self.in_s[k,:,:], extent=self.write_s)
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#Wait for sending to complete
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for comm in comm_send:
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comm.wait()
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####
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# Then transfer east-west including ghost cells that have been filled in by north-south transfer above
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# Fixme: This can be optimized by overlapping the GPU transfer with the pervious MPI transfer if the corners
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# har handled on the CPU
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####
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#Download from the GPU
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for k in range(self.nvars):
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self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_e[k,:,:], async=True, extent=self.read_e)
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self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_w[k,:,:], async=True, extent=self.read_w)
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self.sim.stream.synchronize()
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#Send to east/west neighbours
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comm_send = []
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comm_send += [self.comm.Isend(self.out_e, dest=self.east, tag=4*self.nt + 2)]
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comm_send += [self.comm.Isend(self.out_w, dest=self.west, tag=4*self.nt + 3)]
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#Receive from east/west neighbors
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comm_recv = []
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comm_recv += [self.comm.Irecv(self.in_w, source=self.west, tag=4*self.nt + 2)]
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comm_recv += [self.comm.Irecv(self.in_e, source=self.east, tag=4*self.nt + 3)]
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#Wait for incoming transfers to complete
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for comm in comm_recv:
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comm.wait()
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#Upload to the GPU
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for k in range(self.nvars):
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self.sim.u0[k].upload(self.sim.stream, self.in_e[k,:,:], extent=self.write_e)
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self.sim.u0[k].upload(self.sim.stream, self.in_w[k,:,:], extent=self.write_w)
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#Wait for sending to complete
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for comm in comm_send:
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comm.wait()
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def getCoordinate(self, rank):
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i = (rank % self.grid[0])
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j = (rank // self.grid[0])
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return i, j
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def getRank(self, i, j):
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return j*self.grid[0] + i
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def getEast(self):
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i, j = self.getCoordinate(self.rank)
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i = (i+1) % self.grid[0]
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return self.getRank(i, j)
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def getWest(self):
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i, j = self.getCoordinate(self.rank)
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i = (i+self.grid[0]-1) % self.grid[0]
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return self.getRank(i, j)
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def getNorth(self):
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i, j = self.getCoordinate(self.rank)
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j = (j+1) % self.grid[1]
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return self.getRank(i, j)
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def getSouth(self):
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i, j = self.getCoordinate(self.rank)
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j = (j+self.grid[1]-1) % self.grid[1]
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return self.getRank(i, j)
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def getFactors(number, num_factors):
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# Adapted from https://stackoverflow.com/questions/28057307/factoring-a-number-into-roughly-equal-factors
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# Original code by https://stackoverflow.com/users/3928385/ishamael
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#Dictionary to remember already computed permutations
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memo = {}
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def dp(n, left): # returns tuple (cost, [factors])
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"""
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Recursively searches through all factorizations
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"""
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#Already tried: return existing result
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if (n, left) in memo:
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return memo[(n, left)]
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#Spent all factors: return number itself
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if left == 1:
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return (n, [n])
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#Find new factor
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i = 2
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best = n
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bestTuple = [n]
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while i * i < n:
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#If factor found
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if n % i == 0:
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#Factorize remainder
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rem = dp(n // i, left - 1)
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#If new permutation better, save it
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if rem[0] + i < best:
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best = rem[0] + i
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bestTuple = [i] + rem[1]
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i += 1
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#Store calculation
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memo[(n, left)] = (best, bestTuple)
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return memo[(n, left)]
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assert(isinstance(number, int))
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assert(isinstance(num_factors, int))
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factors = dp(number, num_factors)[1]
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if (len(factors) < num_factors):
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#Split problematic 4
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if (4 in factors):
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factors.remove(4)
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factors.append(2)
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factors.append(2)
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#Pad with ones to guarantee num_factors
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factors = factors + [1]*(num_factors - len(factors))
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#Sort in descending order
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factors = np.flip(np.sort(factors))
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return factors |