from unittest_find import unittest import numpy as np from chroma.geometry import Solid, Geometry from chroma.loader import create_geometry_from_obj from chroma.make import box from chroma.sim import Simulation from chroma.demo.optics import water from chroma.event import Photons from chroma.rootimport import ROOT ROOT.gROOT.SetBatch(1) from chroma.histogram import Histogram, rootify class TestRayleigh(unittest.TestCase): def setUp(self): self.cube = Geometry(water) self.cube.add_solid(Solid(box(100,100,100), water, water)) self.geo = create_geometry_from_obj(self.cube, update_bvh_cache=False) self.sim = Simulation(self.geo, 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(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) dm/tree/src/zebra.h?id=21491ca1ca2afd6951e9b5b1e74b1c919c602b36'>zebra.h
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