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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):
self.nX = nX
self.nY = nY
self.nCells = nX * nY
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_moments = []
self.np_material = numpy.ndarray(shape=(self.nCells, 1), dtype=numpy.int32)
self.setup_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):
self.np_material[:] = 0
for x in range(1,self.nX-1):
for y in range(1,self.nY-1):
if x == 1 or y == 1 or x == self.nX-2 or y == self.nY-2:
self.np_material[self.idx(x,y)] = 2
else:
self.np_material[self.idx(x,y)] = 1
def build_kernel(self):
program_src = Template(filename = './template/kernel.mako').render(
nX = self.nX,
nY = self.nY,
nCells = self.nCells,
tau = '0.8f',
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 collect_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();
self.np_moments.append(moments)
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 generate_moment_plots(self):
for i, moments in enumerate(self.np_moments):
print("Generating plot %d of %d." % (i+1, len(self.np_moments)))
density = numpy.ndarray(shape=(self.nY-2, self.nX-2))
for y in range(1,self.nY-1):
for x in range(1,self.nX-1):
density[y-1,x-1] = moments[0,self.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)
self.np_moments = []
def MLUPS(cells, steps, time):
return cells * steps / time * 1e-6
nUpdates = 1000
nStat = 100
print("Initializing simulation...\n")
LBM = D2Q9_BGK_Lattice(1024, 1024)
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)))
LBM.collect_moments()
lastStat = time.time()
print("\nConcluded simulation.\n")
LBM.generate_moment_plots()
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