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import numpy
import time
import matplotlib
import matplotlib.pyplot as plt
matplotlib.use('AGG')
from lbm import Lattice, Geometry
import symbolic.D2Q9 as D2Q9
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)))
velocity = numpy.ndarray(shape=tuple(reversed(lattice.geometry.inner_span())))
for x, y in lattice.geometry.inner_cells():
velocity[y-1,x-1] = numpy.sqrt(m[1,lattice.idx(x,y)]**2 + m[2,lattice.idx(x,y)]**2)
plt.figure(figsize=(10, 10))
plt.imshow(velocity, origin='lower', cmap=plt.get_cmap('seismic'))
plt.savefig("result/ldc_" + str(i) + ".png", bbox_inches='tight', pad_inches=0)
def cavity(geometry, x, y):
if x == 1 or y == 1 or x == geometry.size_x-2:
return 2
elif y == geometry.size_y-2:
return 3
else:
return 1
boundary = """
if ( m == 2 ) {
u_0 = 0.0;
u_1 = 0.0;
}
if ( m == 3 ) {
u_0 = 0.1;
u_1 = 0.0;
}
"""
nUpdates = 100000
nStat = 5000
moments = []
print("Initializing simulation...\n")
lattice = Lattice(
descriptor = D2Q9,
geometry = Geometry(256, 256),
moments = D2Q9.moments(optimize = False),
collide = D2Q9.bgk(tau = 0.56),
boundary_src = boundary)
lattice.setup_geometry(cavity)
print("Starting simulation using %d cells...\n" % lattice.geometry.volume)
lastStat = time.time()
for i in range(1,nUpdates+1):
lattice.evolve()
if i % nStat == 0:
lattice.sync()
print("i = %4d; %3.0f MLUPS" % (i, MLUPS(lattice.geometry.volume, nStat, time.time() - lastStat)))
moments.append(lattice.get_moments())
lastStat = time.time()
print("\nConcluded simulation.\n")
generate_moment_plots(lattice, moments)
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