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import pyopencl as cl
mf = cl.mem_flags
import numpy
import time
import matplotlib
import matplotlib.pyplot as plt
matplotlib.use('AGG')
import sympy
import lbm_d2q9 as D2Q9
from mako.template import Template
class D2Q9_BGK_Lattice:
def idx(self, x, y):
return y * self.nX + x;
def __init__(self, nX, nY, tau, geometry):
self.nX = nX
self.nY = nY
self.nCells = nX * nY
self.tau = tau
self.tick = True
self.platform = cl.get_platforms()[0]
self.context = cl.Context(properties=[(cl.context_properties.PLATFORM, self.platform)])
self.queue = cl.CommandQueue(self.context)
self.np_material = numpy.ndarray(shape=(self.nCells, 1), dtype=numpy.int32)
self.setup_geometry(geometry)
self.cl_pop_a = cl.Buffer(self.context, mf.READ_WRITE, size=9*self.nCells*numpy.float32(0).nbytes)
self.cl_pop_b = cl.Buffer(self.context, mf.READ_WRITE, size=9*self.nCells*numpy.float32(0).nbytes)
self.cl_moments = cl.Buffer(self.context, mf.WRITE_ONLY, size=3*self.nCells*numpy.float32(0).nbytes)
self.cl_material = cl.Buffer(self.context, mf.READ_ONLY | mf.USE_HOST_PTR, hostbuf=self.np_material)
self.build_kernel()
self.program.equilibrilize(self.queue, (self.nX,self.nY), (32,1), self.cl_pop_a, self.cl_pop_b).wait()
def setup_geometry(self, geometry):
for y in range(1,self.nY-1):
for x in range(1,self.nX-1):
self.np_material[self.idx(x,y)] = geometry(self.nX,self.nY,x,y)
def build_kernel(self):
program_src = Template(filename = './template/kernel.mako').render(
nX = self.nX,
nY = self.nY,
nCells = self.nCells,
tau = self.tau,
moments_helper = D2Q9.moments_opt[0],
moments_assignment = D2Q9.moments_opt[1],
collide_helper = D2Q9.collide_opt[0],
collide_assignment = D2Q9.collide_opt[1],
c = D2Q9.c,
w = D2Q9.w,
ccode = sympy.ccode
)
self.program = cl.Program(self.context, program_src).build()
def evolve(self):
if self.tick:
self.tick = False
self.program.collide_and_stream(self.queue, (self.nX,self.nY), (32,1), self.cl_pop_a, self.cl_pop_b, self.cl_material)
else:
self.tick = True
self.program.collide_and_stream(self.queue, (self.nX,self.nY), (32,1), self.cl_pop_b, self.cl_pop_a, self.cl_material)
def sync(self):
self.queue.finish()
def get_moments(self):
moments = numpy.ndarray(shape=(3, self.nCells), dtype=numpy.float32)
if self.tick:
self.program.collect_moments(self.queue, (self.nX,self.nY), (32,1), self.cl_pop_b, self.cl_moments)
else:
self.program.collect_moments(self.queue, (self.nX,self.nY), (32,1), self.cl_pop_a, self.cl_moments)
cl.enqueue_copy(LBM.queue, moments, LBM.cl_moments).wait();
return moments
def MLUPS(cells, steps, time):
return cells * steps / time * 1e-6
def generate_moment_plots(lattice, moments):
for i, m in enumerate(moments):
print("Generating plot %d of %d." % (i+1, len(moments)))
density = numpy.ndarray(shape=(lattice.nY-2, lattice.nX-2))
for y in range(1,lattice.nY-1):
for x in range(1,lattice.nX-1):
density[y-1,x-1] = m[0,lattice.idx(x,y)]
plt.figure(figsize=(10, 10))
plt.imshow(density, origin='lower', vmin=0.2, vmax=2.0, cmap=plt.get_cmap('seismic'))
plt.savefig("result/density_" + str(i) + ".png", bbox_inches='tight', pad_inches=0)
def box(nX, nY, x, y):
if x == 1 or y == 1 or x == nX-2 or y == nY-2:
return 2
else:
return 1
nUpdates = 1000
nStat = 100
moments = []
print("Initializing simulation...\n")
LBM = D2Q9_BGK_Lattice(nX = 1024, nY = 1024, tau = 0.8, geometry = box)
print("Starting simulation using %d cells...\n" % LBM.nCells)
lastStat = time.time()
for i in range(1,nUpdates+1):
LBM.evolve()
if i % nStat == 0:
LBM.sync()
print("i = %4d; %3.0f MLUPS" % (i, MLUPS(LBM.nCells, nStat, time.time() - lastStat)))
moments.append(LBM.get_moments())
lastStat = time.time()
print("\nConcluded simulation.\n")
generate_moment_plots(LBM, moments)
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