source: fact/tools/pyscripts/simulation/old_and_tests/reflector_test_ray.py@ 18123

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1#!/usr/bin/python -itt
2
3import struct
4import sys
5import numpy as np
6from pprint import pprint
7import rlcompleter
8import readline
9readline.parse_and_bind('tab: complete')
10from ROOT import *
11import readcorsika
12import matplotlib.pyplot as plt
13
14def dot( v1, v2):
15 return (v1*v2).sum()
16
17def length( v ):
18 return np.sqrt((v**2).sum())
19
20def cross(v1 , v2, normalize=True):
21 vout = np.zeros( v1.shape )
22
23 vout[0] = v1[1]*v2[2] - v1[2]*v2[1]
24 vout[1] = -(v1[0]*v2[2] - v1[2]*v2[0])
25 vout[2] = v1[0]*v2[1] - v1[1]*v2[0]
26
27 if normalize:
28 vout /= length(vout)
29
30 return vout
31
32def matrix_times_vector( m , v):
33 vout = v.copy()
34 for index,line in enumerate(m):
35 vout[index] = dot(line,v)
36
37 return vout
38
39def make_rotation_matrix( nn, a ):
40 R = np.zeros( (3,3) )
41 R[0,0] = nn[0]*nn[0] * (1-np.cos(a)) + np.cos(a)
42 R[1,0] = nn[0]*nn[1] * (1-np.cos(a)) + nn[2]*np.sin(a)
43 R[2,0] = nn[0]*nn[2] * (1-np.cos(a)) - nn[1]*np.sin(a)
44
45 R[0,1] = nn[0]*nn[1] * (1-np.cos(a)) - nn[2]*np.sin(a)
46 R[1,1] = nn[1]*nn[1] * (1-np.cos(a)) + np.cos(a)
47 R[2,1] = nn[1]*nn[2] * (1-np.cos(a)) + nn[0]*np.sin(a)
48
49 R[0,2] = nn[0]*nn[2] * (1-np.cos(a)) + nn[1]*np.sin(a)
50 R[1,2] = nn[1]*nn[2] * (1-np.cos(a)) - nn[0]*np.sin(a)
51 R[2,2] = nn[2]*nn[2] * (1-np.cos(a)) + np.cos(a)
52
53 return R
54
55class Thing( object ):
56 """ Thing is just a container for the postion and the direction
57 of something.
58 A Thing can be a particle, or photon or something like that
59 Or it can be a plane, like a mirror-plane or a focal-plane.
60 Then the *dir* vector is the normal vector of the plane, and
61 *pos* is one (possibly important) point inside the plane.
62 """
63 def __init__(self, pos, dir):
64 self.pos = pos
65 self.dir = dir
66
67 def turn(self, axis, angle):
68 """ axis might not be normalized
69 and angle might be in degree
70 """
71 if length(axis) != 1.:
72 axis /= length(axis)
73
74 angle = angle / 180. *np.pi
75
76
77
78 R = make_rotation_matrix( turning_axis, angle )
79 self.pos = matrix_times_vector( R, self.pos)
80 self.dir = matrix_times_vector( R, self.dir)
81
82
83 def _old_turn( self, theta, phi):
84 theta = theta/180.*np.pi
85 phi = phi/180.*np.pi
86
87 x= self.pos[0]
88 y= self.pos[1]
89 z= self.pos[2]
90
91 vx= self.dir[0]
92 vy= self.dir[1]
93 vz= self.dir[2]
94
95 #print vx,vy,vz
96
97 #transform into spehrical coordinates
98 print x,y,z
99 r = length(self.pos)
100 p = np.arctan2(y,x)
101 t = np.arccos(z/r)
102 print r,t,p
103
104 v = length(self.dir)
105 vp = np.arctan2(vy,vx)
106 vt = np.arccos(vz/v)
107
108 #print v,vt,vp
109
110 # actual turning takes place
111 t += theta
112 p += phi
113
114 vt += theta
115 vp += phi
116
117 #print v,vt,vp
118
119 #back transform
120
121 x = r * np.sin(t) * np.cos(p)
122 y = r * np.sin(t) * np.sin(p)
123 z = r * np.cos(t)
124
125 vx = v * np.sin(vt) * np.cos(vp)
126 vy = v * np.sin(vt) * np.sin(vp)
127 vz = v * np.cos(vt)
128
129 #print vx,vy,vz
130
131 # set internal vars
132 self.pos = np.array([x,y,z])
133 self.dir = np.array([vx,vy,vz])
134
135
136 def __repr__( self ):
137 return "%s(%r)" % (self.__class__, self.__dict__)
138
139class Mirror( Thing ):
140 def __init__(self, index, pos, normal_vector, focal_length, hex_size ):
141 super(Mirror,self).__init__(pos, normal_vector)
142 self.index = index
143 self.focal_length = focal_length
144 self.hex_size = hex_size
145
146 def __repr__( self ):
147 return "%s(%r)" % (self.__class__, self.__dict__)
148
149
150
151
152
153
154def read_reflector_definition_file( filename ):
155 """
156 """
157 mirrors = []
158
159 f = open( filename )
160 for index, line in enumerate(f):
161 if line[0] == '#':
162 continue
163 line = line.split()
164 if len(line) < 8:
165 continue
166 #print line
167
168 # first 3 colums in the file are x,y,z coordinates of the center
169 # of this mirror in cm, I guess
170 pos = np.array(map(float, line[0:3]))
171
172 # the next 3 elements are the elements of the normal vector
173 # should be normalized already, so the unit is of no importance.
174 normal_vector = np.array(map(float,line[3:6]))
175
176 # focal length of this mirror in mm
177 focal_length = float(line[6])
178
179 # size of the hexagonal shaped facette mirror, measured as the radius
180 # of the hexagons *inner* circle.
181 hex_size = float(line[8])
182 mirror = Mirror( index, pos, normal_vector, focal_length, hex_size )
183
184 mirrors.append(mirror)
185
186 return mirrors
187
188
189
190
191def reflect_photon( photon, mirrors):
192 """ finds out:
193 which mirror is hit by photon
194 and where
195 and in which angle relative to mirror
196 """
197
198 # the line defined by the photon is used to find the intersection point
199 # with the plane of each facette mirror. Then I check,
200 # if the intersection point lies within the limits of the facette mirrors
201 # hexagonal boundaries.
202 # If this is the case I have found the mirror, which is hit, and
203 # can calculate:
204 # the distance of the intersection point from the center of the facette mirror
205 # and the angle relative to the mirror (normal or plane not sure yet)
206
207 for mirror in mirrors:
208 #facette mirror plane, defined as n . x = d1 . n
209 n = mirror.dir
210 d1 = mirror.pos
211
212 # line of photon defined as r = lambda * v + d2
213 v = photon.dir
214 d2 = photon.pos
215
216 # the intersection coordinates are found by solving
217 # n . (lambda * v + d2) - d1 . n == 0, for lambda=lambda_0
218 # and then the intersection is: i = lambda_0 * v + d2
219 #
220 # putting int in another form:
221 # solve:
222 # lambda * n.v + n.d2 - n.d1 == 0
223 # or
224 # lambda_0 = n.(d1-d2) / n.v
225
226 # FIXME: if one of the two dot-products is very small,
227 # we shuold take special care maybe
228 # if n.(d1-d2) is very small, this means that the starting point of
229 # the photon is already nearly in the plane, so lambda_0 is expected to
230 # be very small ... erm .. maybe this is actually not a special case
231 # but very good.
232 # of n.v is very small, this means the patch of the photon is nearly
233 # parallel to the plane, so the error ob lambda_0 might be very large.
234 # in addition, this might just tell us, that the mirror is hit under
235 # strange circumstances ... so its not a good candidate and we can already go on.
236 lambda_0 = (dot(n,(d1-d2)) / dot(n,v))
237
238 #intersection between line and plane
239 i = lambda_0 * v + d2
240
241 # I want the distance beween i and d1 so I can already from the distance find
242 # out if this is our candidate.
243 distance = np.sqrt(((i-d1)*(i-d1)).sum())
244
245 #print "photon pos:", d2, "\t dir:", v/length(v)
246 #print "mirror pos:", d1, "\t dir:", n/length(n)
247
248 #print "lambda_0", lambda_0
249 #print "intersection :", i
250 #print "distance:",distance
251
252 if distance <= mirror.hex_size/2.:
253 break
254 else:
255 mirror = None
256
257 if not mirror is None:
258 photon.mirror_index = mirror.index
259 photon.mirror_intersection = i
260 photon.mirror_center_distance = distance
261 #print "mirror found:", mirror.index ,
262 #print "distance", distance
263 # now I have to find out, if the photon is not only in the
264 # right distance but actually has hit the mirror.
265 # this I do like this
266 # i-d1 is a vector in the mirror plane pointing from d1 to the intersection point i.
267 # if I know turn the entire mirror plane so it lies withing the x-y-plane
268 # by applying a simple turning-matrix, then each vector inside the plane with turn into
269 # a nice x,x vector.
270 # now I assume, that the hexagon is "pointing" lets say to into y direction
271 # so I can e.g. say:
272 # x has to be between -30.3 and +30.3 and y has to be
273 # between 35 - m * |x| and -35 + m * |x| ... pretty simple.
274 # maybe one can leave the turning aside, but I like that I can imagine it very nicely
275 #
276 #
277 # I don't do this yet .. since I don't know by heart how a turning matrix looks :-)
278 # so I just simulate round mirrors
279 ######################################################################
280
281
282 # next step, since I know the intersection point, is the new direction.
283 # So I need the normal of the mirror in the intersection point.
284 # since the normal of every mirror is alway pointing to the camera center
285 # this is not difficult.
286
287 normal_at_intersection = (mirror_alignmen_point.pos - i) / length(mirror_alignmen_point.pos - i)
288 #print "normal_at_intersection",normal_at_intersection
289
290 angle = np.arccos(dot( v, normal_at_intersection) / (length(v) * length(normal_at_intersection)))
291 photon.angle_to_mirror_normal = angle
292 #print "angle:", angle/np.pi*180., "deg"
293
294
295 # okay, now I have the intersection *i*,
296 # the old direction of the photon *v*
297 # and the normalvector at the intersection.
298 ######################################################################
299 ######################################################################
300 # I do this now differently.
301 # I will mirror the "point" at the tip of *v* at the line created by
302 # the normalvector at the intersection and the intersection.
303 # this will gibe me a mirrored_point *mp* and the vector from *i* to *mp*
304 # is the *new_direction* it should even be normalized.
305
306 # 1. step: create plane through the "tip" of *v* and the normal_at_intersection.
307 # 2. step: find crossingpoint on line through *i* and the normal_at_intersection,
308 # 3. step: vector from "tip" of *v* to crossingpoint times 2 points to
309 # the "tip" of *mirrored_v*
310
311 # plane: n_plane_3 . r = p_plane_3 . n_plane_3
312 # p_plane_3 = i+v
313 # n_plane_3 = normal_at_intersection
314
315 # line: r = lambda_3 * v_line_3 + p_line_3
316 # p_line_3 = i
317 # v_line_3 = normal_at_intersection
318
319 # create crossing: n_plane_3 . (lambda_3 * v_line_3 + p_line_3) = p_plane_3 . n_plane_3
320 # <=> lambda_3 = (p_plane_3 - p_line_3 ).n_plane_3 / n_plane_3 . v_line_3
321 # <=> lambda_3 = (i+v - i).normal_at_intersection / normal_at_intersection . normal_at_intersection
322 # <=> lambda_3 = v.normal_at_intersection
323
324 lambda_3 = dot(v, normal_at_intersection)
325 #print "lambda_3", lambda_3
326 crossing_point_3 = lambda_3 * normal_at_intersection + i
327 #print "crossing_point_3", crossing_point_3
328
329 from_tip_of_v_to_crossing_point_3 = crossing_point_3 - (i+v)
330
331 tip_of_mirrored_v = i+v+ 2*from_tip_of_v_to_crossing_point_3
332
333 new_direction = tip_of_mirrored_v - i
334
335 #print "new_direction",new_direction
336 #print "old direction", v
337 photon.new_direction = new_direction
338 ######################################################################
339 ######################################################################
340 """
341 # both directions form a plane, and when I turn the old *v* by
342 # twice the angle between *v* and *normal_at_intersection*
343 # inside this plane then I get the new direction of the photon.
344
345 # so lets first get the normal of the reflection plane
346 normal_of_reflection_plane =cross( v, normal_at_intersection)
347
348 print length(normal_of_reflection_plane), "should be one"
349 print length(v), "should be one"
350 print length(normal_at_intersection), "should be one"
351 print dot(v, normal_at_intersection), "should *NOT* be zero"
352 print dot(v, normal_of_reflection_plane), "should be zero"
353 print dot(normal_at_intersection, normal_of_reflection_plane), "should be zero"
354
355 angle = np.arccos(dot( v, normal_at_intersection) / (length(v) * length(normal_at_intersection)))
356 photon.angle_to_mirror_normal = angle
357 print "angle:", angle/np.pi*180., "deg"
358
359 # the rotation matrix for the rotation of *v* around normal_of_reflection_plane is
360 R = make_rotation_matrix( normal_of_reflection_plane, 2*angle )
361
362 print "R"
363 pprint(R)
364
365 new_direction = matrix_times_vector( R, v)
366 photon.new_direction = new_direction
367
368 print "old direction", v, length(v)
369 print "new direction", new_direction, length(new_direction)
370 print "mirror center", mirror.pos
371 print "interception point", i
372 print "center of focal plane", focal_plane.pos
373 """
374
375 # new the photon has a new direction *new_direction* and is starting
376 # from the intersection point *i*
377 # now I want to find out where there focal plane is hit.
378 # So I have to repeat the stuff from up there
379
380 #print "dot(focal_plane.dir,new_direction))", dot(focal_plane.dir,new_direction)
381
382 lambda_1 = (dot(focal_plane.dir ,(focal_plane.pos - i)) / dot(focal_plane.dir,new_direction))
383
384 #print "lambda_1", lambda_1
385 focal_plane_spot = lambda_1 * new_direction + i
386 #print "focal_plane_spot",focal_plane_spot
387 photon.hit = True
388 photon.focal_plane_pos = focal_plane_spot - focal_plane.pos
389
390 #print "distance from focal plane center=", length(focal_plane_spot-focal_plane.pos)
391 else:
392 photon.hit = False
393
394
395 return photon
396
397class Photon( Thing ):
398 """ a photon has not only the direction and position, which a Thing has.
399 but it also has a wavelength and a "time" and a "mother_particle_id"
400
401 the photon constructor understands the 10-element 1D-np.array
402 which is stored inside a run.event.photons 2D-np.array
403 """
404 def __init__(self, photon_definition_array ):
405 """ the *photon_definition_array* pda contains:
406 pda[0] - encoded info
407 pda[1:3] - x,y position in cm
408 pda[3:5] - u,v cosines to x,y axis --> so called direction cosines
409 pda[5] - time since first interaction [ns]
410 pda[6] - height of production in cm
411 pda[7] - j ??
412 pda[8] - imov ??
413 pda[9] - wavelength [nm]
414 """
415 pda = photon_definition_array
416 pos = np.array([pda[1],pda[2],0.])
417 dir = np.array([pda[3],pda[4], np.sqrt(1-pda[3]**2-pda[4]**2) ])
418 super(Photon,self).__init__(pos, dir)
419
420 self.wavelength = pda[9]
421 self.time = pda[5]
422
423 def __repr__( self ):
424 return "%s(%r)" % (self.__class__, self.__dict__)
425
426
427if __name__ == '__main__':
428 mirrors = read_reflector_definition_file( "030/reflector_test_ray.py" )
429
430
431 focal_plane = Thing( pos=np.array([0.,0.,978.132/2.]), # center of focal_plane
432 dir=np.array([0., 0., 1.]) ) # direction of view
433 focal_plane.size = 20 # diameter in cm
434
435
436 mirror_alignmen_point = Thing( pos=np.array([0.,0.,978.132]), # center of focal_plane
437 dir=np.array([0., 0., 1.]) ) # direction of view
438
439
440
441 # turn the telescope
442
443 turning_axis = np.array([-1,0,0])
444 angle = 30.
445
446 for mirror in mirrors:
447 mirror.turn( turning_axis, angle)
448
449 focal_plane.turn( turning_axis, angle)
450 mirror_alignmen_point.turn( turning_axis, angle)
451
452
453 #run = readcorsika.read_corsika_file("cer")
454
455 li=[]
456
457 photons_who_hit = []
458 for photon_index in range(2000):
459 if photon_index % 10 == 0:
460 print photon_index
461
462 # make test photon directly from up to down
463 p = 87.5 + (photon_index/2000.*5.)
464 p = p/180.*np.pi
465
466 t = 27.5 + (photon_index/2000.*5.)
467 t = t/180.*np.pi
468 dir = np.array([np.sin(t)*np.cos(p),np.sin(t)*np.sin(p),np.cos(t)])
469
470
471 pos = (np.random.rand(3)-0.5)*450
472 pos[2] = 0.
473 photon = Thing( pos=pos, dir=dir)
474
475 photon = reflect_photon( photon, mirrors )
476
477 if photon.hit:
478 li.append( photon.angle_to_mirror_normal / np.pi * 180.)
479 photons_who_hit.append(photon)
480
481
482 #plt.ion()
483 #fig1 = plt.figure()
484 #fig2 = plt.figure()
485
486 #plt.hist( np.array(li) , bins=100)
487 plt.hold(False)
488
489
490 g = TGraph2D()
491 h = TH2F("h","title",100,-100.5,99.5,100,-100.5,99.5)
492 c1 = TCanvas("c1","c1 title",0,0,400,400)
493 c2 = TCanvas("c2","c2 title",0,400,400,400)
494
495 c = 0
496 ground_dirs = []
497 focal_positions = []
498 print len(photons_who_hit)
499 for ph in photons_who_hit:
500 mi = ph.mirror_intersection
501 #new = Thing( pos=ph.focal_plane_pos, dir = ph.new_direction)
502 #new.turn( np.array([0,1,0]), 0 )
503 fpp = ph.focal_plane_pos
504 #print mi
505 h.Fill(fpp[0], fpp[1])
506 g.SetPoint( c, mi[0], mi[1], mi[2])
507 c += 1
508 #ground_dirs.append(ph.dir)
509 #focal_positions.append(new.pos)
510
511 #ground_dirs = np.array(ground_dirs)
512 #focal_positions = np.array(focal_positions)
513 #print ground_dirs.shape, focal_positions.shape
514 #plt.figure(fig1.number)
515 #plt.plot( ground_dirs[:,0], ground_dirs[:,1], '.')
516 #plt.title("ground directions")
517 #plt.figure(fig2.number)
518 #plt.plot( focal_positions[:,0], focal_positions[:,1], '.')
519 #plt.title("focal positions")
520
521
522 #raw_input()
523
524 g.SetMarkerStyle(20)
525 c1.cd()
526 g.Draw("pcol")
527 c1.Update()
528
529 c2.cd()
530 h.Draw("colz")
531 c2.Update()
532
533
534
535
536"""
537 for m in mirrors:
538 mi = m.pos
539 #mi = ph.focal_plane_pos
540 g.SetPoint( c, mi[0], mi[1], mi[2])
541 c += 1
542"""
543
544
545
546
547
548
549
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