From d71faec93ec0a55c46810e0d178b2803ee89130c Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sat, 15 Jun 2019 20:45:27 +0200
Subject: Add support for generating a D3Q19 kernel

Note how this basically required no changes besides generalizing cell indexing
and adding the symbolic formulation of a D3Q19 BGK collision step.

Increasing the neighborhood communication from 9 to 19 cells leads to a
significant performance "regression": The 3D kernel yields ~ 360 MLUPS
compared to the 2D version's ~ 820 MLUPS.
---
 ldc_3d.py | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 ldc_3d.py

(limited to 'ldc_3d.py')

diff --git a/ldc_3d.py b/ldc_3d.py
new file mode 100644
index 0000000..62f820e
--- /dev/null
+++ b/ldc_3d.py
@@ -0,0 +1,97 @@
+import numpy
+import time
+
+import matplotlib
+import matplotlib.pyplot as plt
+matplotlib.use('AGG')
+
+from lbm import Lattice, Geometry
+
+import symbolic.D3Q19 as D3Q19
+
+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())))
+
+        # plot x-z-plane
+        y = lattice.geometry.size_y//2
+        for z in range(1,lattice.geometry.size_z-1):
+            for x in range(1,lattice.geometry.size_x-1):
+                velocity[z-1,y,x-1] = numpy.sqrt(m[1,lattice.idx(x,y,z)]**2 + m[2,lattice.idx(x,y,z)]**2 + m[3,lattice.idx(x,y,z)]**2)
+
+        plt.figure(figsize=(20, 10))
+
+        plt.subplot(1, 2, 1)
+        plt.imshow(velocity[:,y,:], origin='lower', vmin=0.0, vmax=0.12, cmap=plt.get_cmap('seismic'))
+
+        # plot y-z-plane
+        x = lattice.geometry.size_x//2
+        for z in range(1,lattice.geometry.size_z-1):
+            for y in range(1,lattice.geometry.size_y-1):
+                velocity[z-1,y-1,x] = numpy.sqrt(m[1,lattice.idx(x,y,z)]**2 + m[2,lattice.idx(x,y,z)]**2 + m[3,lattice.idx(x,y,z)]**2)
+
+        plt.subplot(1, 2, 2)
+        plt.imshow(velocity[:,:,x], origin='lower', vmin=0.0, vmax=0.15, cmap=plt.get_cmap('seismic'))
+
+        plt.savefig("result/ldc_3d_%02d.png" % i, bbox_inches='tight', pad_inches=0)
+
+def cavity(geometry, x, y, z):
+    if x == 1 or y == 1 or z == 1 or x == geometry.size_x-2 or y == geometry.size_y-2:
+        return 2
+    elif z == geometry.size_z-2:
+        return 3
+    else:
+        return 1
+
+boundary = """
+    if ( m == 2 ) {
+        u_0 = 0.0;
+        u_1 = 0.0;
+        u_2 = 0.0;
+    }
+    if ( m == 3 ) {
+        u_0 = 0.1;
+        u_1 = 0.0;
+        u_2 = 0.0;
+    }
+"""
+
+nUpdates = 20000
+nStat    = 500
+
+moments = []
+
+print("Initializing simulation...\n")
+
+lattice = Lattice(
+    descriptor = D3Q19,
+    geometry   = Geometry(128, 128, 128),
+
+    moments = D3Q19.moments(optimize = False),
+    collide = D3Q19.bgk(tau = 0.52),
+
+    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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