1 files changed, 67 insertions, 0 deletions
diff --git a/Examples/Tests/collision/analysis_collision.py b/Examples/Tests/collision/analysis_collision.py
new file mode 100755
index 000000000..25fa26e4b
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+++ b/Examples/Tests/collision/analysis_collision.py
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+#! /usr/bin/env python
+
+# This script tests the collision module
+# using electron-ion temperature relaxation.
+# Initially, electrons and ions are both in equilibrium
+# (gaussian) distributions, but have different temperatures.
+# Relaxation occurs to bring the two temeratures to be
+# a final same temperature through collisions.
+# The code was tested to be valid, more detailed results
+# were used to obtian an exponential fit with
+# coefficients a and b.
+# This automated test compares the results with the fit.
+
+# Possible errors:
+# tolerance: 0.001
+# Possible running time: ~ 30.0 s
+
+import sys
+import yt
+import re
+import math
+import statistics
+from glob import glob
+
+tolerance = 0.001
+
+ng = 512
+ne = ng * 200
+ni = ng * 200
+np = ne + ni
+
+c  = 299792458.0
+me = 9.10938356e-31
+mi = me * 5.0
+
+# exponential fit coefficients
+a =  0.041817463099883
+b = -0.083851393560288
+
+last_fn = sys.argv[1]
+temp = re.compile("([a-zA-Z_]+)([0-9]+)")
+res = temp.match(last_fn).groups()
+fn_list = glob(res[0] + "?????")
+
+error = 0.0
+nt = 0
+for fn in fn_list:
+    # load file
+    ds  = yt.load( fn )
+    ad  = ds.all_data()
+    px  = ad['particle_momentum_x'].to_ndarray()
+    # get time index j
+    buf = temp.match(fn).groups()
+    j = int(buf[1])
+    # compute error
+    vxe = statistics.mean(px[ 0:ne])/me/c
+    vxi = statistics.mean(px[ne:np])/mi/c
+    vxd = vxe - vxi
+    fit = a*math.exp(b*j)
+    error = error + abs(fit-vxd)
+    nt = nt + 1
+
+error = error / nt
+
+print('error = ', error)
+print('tolerance = ', tolerance)
+assert(error < tolerance)