Move CUDA source inside chroma package, rename tests directory to test

1 files changed, 57 insertions, 0 deletions

diff --git a/test/test_rayleigh.py b/test/test_rayleigh.py
new file mode 100644
index 0000000..02ccb41
--- /dev/null
+++ b/test/test_rayleigh.py
@@ -0,0 +1,57 @@
+import unittest
+import numpy as np
+
+from chroma.geometry import Solid, Geometry
+from chroma.make import box
+from chroma.sim import Simulation
+from chroma.optics import water_wcsim
+from chroma.event import Photons
+import histogram
+from histogram.root import rootify
+import ROOT
+ROOT.gROOT.SetBatch(1)
+
+class TestRayleigh(unittest.TestCase):
+    def setUp(self):
+        self.cube = Geometry(water_wcsim)
+        self.cube.add_solid(Solid(box(100,100,100), water_wcsim, water_wcsim))
+        self.cube.pmtids = [0]
+        self.cube.build(use_cache=False)
+        self.sim = Simulation(self.cube, geant4_processes=0)
+
+        nphotons = 100000
+        pos = np.tile([0,0,0], (nphotons,1)).astype(np.float32)
+        dir = np.tile([0,0,1], (nphotons,1)).astype(np.float32)
+        pol = np.zeros_like(pos)
+        phi = np.random.uniform(0, 2*np.pi, nphotons).astype(np.float32)
+        pol[:,0] = np.cos(phi)
+        pol[:,1] = np.sin(phi)
+        t = np.zeros(nphotons, dtype=np.float32)
+        wavelengths = np.empty(nphotons, np.float32)
+        wavelengths.fill(400.0)
+
+        self.photons = Photons(pos=pos, dir=dir, pol=pol, t=t, wavelengths=wavelengths)
+
+    def testAngularDistributionPolarized(self):
+        # Fully polarized photons
+        self.photons.pol[:] = [1.0, 0.0, 0.0]
+
+        photons_end = self.sim.simulate([self.photons], keep_photons_end=True, max_steps=1).next().photons_end
+        aborted = (photons_end.flags & (1 << 31)) > 0
+        self.assertFalse(aborted.any())
+
+        # Compute the dot product between initial and final dir
+        rayleigh_scatters = (photons_end.flags & (1 << 4)) > 0
+        cos_scatter = (self.photons.dir[rayleigh_scatters] * photons_end.dir[rayleigh_scatters]).sum(axis=1)
+        theta_scatter = np.arccos(cos_scatter)
+        h = histogram.Histogram(bins=100, range=(0, np.pi))
+        h.fill(theta_scatter)
+        h = rootify(h)
+
+        # The functional form for polarized light should be
+        # (1 + \cos^2 \theta)\sin \theta according to GEANT4 physics
+        # reference manual.
+        f = ROOT.TF1("pol_func", "[0]*(1+cos(x)**2)*sin(x)", 0, np.pi)
+        h.Fit(f)
+        self.assertGreater(f.GetProb(), 1e-3)
+