Added ITS Alignment interface to MillePede2 and related supermodule class
[u/mrichter/AliRoot.git] / FMD / AliFMDHitDigitizer.cxx
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ef8e8623 1/**************************************************************************
2 * Copyright(c) 2004, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15/* $Id: AliFMDHitDigitizer.cxx 28055 2008-08-18 00:33:20Z cholm $ */
16/** @file AliFMDHitDigitizer.cxx
17 @author Christian Holm Christensen <cholm@nbi.dk>
18 @date Mon Mar 27 12:38:26 2006
19 @brief FMD Digitizers implementation
20 @ingroup FMD_sim
21*/
22//////////////////////////////////////////////////////////////////////////////
23//
24// This class contains the procedures simulation ADC signal for the
25// Forward Multiplicity detector : Hits->Digits
26//
27// Digits consists of
28// - Detector #
29// - Ring ID
30// - Sector #
31// - Strip #
32// - ADC count in this channel
33//
34// As the Digits and SDigits have so much in common, the classes
35// AliFMDHitDigitizer and AliFMDSDigitizer are implemented via a base
36// class AliFMDBaseDigitizer.
37//
38// +---------------------+
39// | AliFMDBaseDigitizer |
40// +---------------------+
41// ^
42// |
43// +----------+---------+
44// | |
45// +-----------------+ +------------------+
46// | AliFMDHitDigitizer | | AliFMDSDigitizer |
47// +-----------------+ +------------------+
48//
49// These classes has several paramters:
50//
51// fPedestal
52// fPedestalWidth
53// (Only AliFMDHitDigitizer)
54// Mean and width of the pedestal. The pedestal is simulated
55// by a Guassian, but derived classes my override MakePedestal
56// to simulate it differently (or pick it up from a database).
57//
58// fVA1MipRange
59// The dymamic MIP range of the VA1_ALICE pre-amplifier chip
60//
61// fAltroChannelSize
62// The largest number plus one that can be stored in one
63// channel in one time step in the ALTRO ADC chip.
64//
65// fSampleRate
66// How many times the ALTRO ADC chip samples the VA1_ALICE
67// pre-amplifier signal. The VA1_ALICE chip is read-out at
68// 10MHz, while it's possible to drive the ALTRO chip at
69// 25MHz. That means, that the ALTRO chip can have time to
70// sample each VA1_ALICE signal up to 2 times. Although it's
71// not certain this feature will be used in the production,
72// we'd like have the option, and so it should be reflected in
73// the code.
74//
75// These parameters are fetched from OCDB via the mananger AliFMDParameters.
76//
77// The shaping function of the VA1_ALICE is generally given by
78//
79// f(x) = A(1 - exp(-Bx))
80//
81// where A is the total charge collected in the pre-amp., and B is a
82// paramter that depends on the shaping time of the VA1_ALICE circut.
83//
84// When simulating the shaping function of the VA1_ALICe
85// pre-amp. chip, we have to take into account, that the shaping
86// function depends on the previous value of read from the pre-amp.
87//
88// That results in the following algorithm:
89//
90// last = 0;
91// FOR charge IN pre-amp. charge train DO
92// IF last < charge THEN
93// f(t) = (charge - last) * (1 - exp(-B * t)) + last
94// ELSE
95// f(t) = (last - charge) * exp(-B * t) + charge)
96// ENDIF
97// FOR i IN # samples DO
98// adc_i = f(i / (# samples))
99// DONE
100// last = charge
101// DONE
102//
103// Here,
104//
105// pre-amp. charge train
106// is a series of 128 charges read from the VA1_ALICE chip
107//
108// # samples
109// is the number of times the ALTRO ADC samples each of the 128
110// charges from the pre-amp.
111//
112// Where Q is the total charge collected by the VA1_ALICE
113// pre-amplifier. Q is then given by
114//
115// E S
116// Q = - -
117// e R
118//
119// where E is the total energy deposited in a silicon strip, R is the
120// dynamic range of the VA1_ALICE pre-amp (fVA1MipRange), e is the
121// energy deposited by a single MIP, and S ALTRO channel size in each
122// time step (fAltroChannelSize).
123//
124// The energy deposited per MIP is given by
125//
126// e = M * rho * w
127//
128// where M is the universal number 1.664, rho is the density of
129// silicon, and w is the depth of the silicon sensor.
130//
131// The final ADC count is given by
132//
133// C' = C + P
134//
135// where P is the (randomized) pedestal (see MakePedestal)
136//
137// This class uses the class template AliFMDMap<Type> to make an
138// internal cache of the energy deposted of the hits. The class
139// template is instantasized as
140//
141// typedef AliFMDMap<std::pair<Float_t, UShort_t> > AliFMDEdepMap;
142//
143// The first member of the values is the summed energy deposition in a
144// given strip, while the second member of the values is the number of
145// hits in a given strip. Using the second member, it's possible to
146// do some checks on just how many times a strip got hit, and what
147// kind of error we get in our reconstructed hits. Note, that this
148// information is currently not written to the digits tree. I think a
149// QA (Quality Assurance) digit tree is better suited for that task.
150// However, the information is there to be used in the future.
151//
152//
153// Latest changes by Christian Holm Christensen
154//
155//////////////////////////////////////////////////////////////////////////////
156
157// /1
158// | A(-1 + B + exp(-B))
159// | f(x) dx = ------------------- = 1
160// | B
161// / 0
162//
163// and B is the a parameter defined by the shaping time (fShapingTime).
164//
165// Solving the above equation, for A gives
166//
167// B
168// A = ----------------
169// -1 + B + exp(-B)
170//
171// So, if we define the function g: [0,1] -> [0:1] by
172//
173// / v
174// | Bu + exp(-Bu) - Bv - exp(-Bv)
175// g(u,v) = | f(x) dx = -A -----------------------------
176// | B
177// / u
178//
179// we can evaluate the ALTRO sample of the VA1_ALICE pre-amp between
180// any two times (u, v), by
181//
182//
183// B Bu + exp(-Bu) - Bv - exp(-Bv)
184// C = Q g(u,v) = - Q ---------------- -----------------------------
185// -1 + B + exp(-B) B
186//
187// Bu + exp(-Bu) - Bv - exp(-Bv)
188// = - Q -----------------------------
189// -1 + B + exp(-B)
190//
191
192#include <TTree.h> // ROOT_TTree
193#include "AliFMDDebug.h" // Better debug macros
194#include "AliFMDHitDigitizer.h" // ALIFMDDIGITIZER_H
195#include "AliFMD.h" // ALIFMD_H
196#include "AliFMDDigit.h" // ALIFMDDIGIT_H
197#include "AliFMDParameters.h" // ALIFMDPARAMETERS_H
198#include <AliRun.h> // ALIRUN_H
199#include <AliLoader.h> // ALILOADER_H
200#include <AliRunLoader.h> // ALIRUNLOADER_H
201#include <AliFMDHit.h>
83ad576a 202#include <AliStack.h>
ef8e8623 203#include <TFile.h>
83ad576a 204#include <TParticle.h>
ef8e8623 205
206//====================================================================
207ClassImp(AliFMDHitDigitizer)
208#if 0
209;
210#endif
211
212//____________________________________________________________________
213AliFMDHitDigitizer::AliFMDHitDigitizer(AliFMD* fmd, Output_t output)
214 : AliFMDBaseDigitizer("FMD", (fOutput == kDigits ?
215 "FMD Hit->Digit digitizer" :
216 "FMD Hit->SDigit digitizer")),
83ad576a 217 fOutput(output),
b2e6f0b0 218 fHoldTime(2e-6),
83ad576a 219 fStack(0)
ef8e8623 220{
221 fFMD = fmd;
222}
223
224//____________________________________________________________________
225void
226AliFMDHitDigitizer::Exec(Option_t* /*option*/)
227{
228 // Run this digitizer
229 // Get an inititialize parameter manager
230 AliFMDParameters::Instance()->Init();
231 if (AliLog::GetDebugLevel("FMD","") >= 10)
232 AliFMDParameters::Instance()->Print("ALL");
233
234 // Get loader, and ask it to read in the hits
235 AliLoader* loader = fFMD->GetLoader();
236 if (!loader) {
237 AliError("Failed to get loader from detector object");
238 return;
239 }
240 loader->LoadHits("READ");
241
242 // Get the run loader
243 AliRunLoader* runLoader = loader->GetRunLoader();
244 if (!runLoader) {
245 AliError("Failed to get run loader from loader");
246 return;
247 }
248
249 // Now loop over events
250 Int_t nEvents = runLoader->GetNumberOfEvents();
251 for (Int_t event = 0; event < nEvents; event++) {
252 // Get the current event folder.
253 TFolder* folder = loader->GetEventFolder();
254 if (!folder) {
255 AliError("Failed to get event folder from loader");
256 return;
257 }
258
259 // Get the run-loader of this event.
260 const char* loaderName = AliRunLoader::GetRunLoaderName();
261 AliRunLoader* thisLoader =
262 static_cast<AliRunLoader*>(folder->FindObject(loaderName));
263 if (!thisLoader) {
264 AliError(Form("Failed to get loader '%s' from event folder", loaderName));
265 return;
266 }
267
268 // Read in the event
269 AliFMDDebug(5, ("Now digitizing (Hits->%s) event # %d",
270 (fOutput == kDigits ? "digits" : "sdigits"), event));
271 thisLoader->GetEvent(event);
272
83ad576a 273 // Load kinematics to get primary information for SDigits
274 fStack = 0;
275 if (fOutput == kSDigits) {
276 if (thisLoader->LoadKinematics("READ")) {
277 AliError("Failed to get kinematics from event loader");
278 return;
279 }
280 AliFMDDebug(5, ("Loading stack of kinematics"));
281 fStack = thisLoader->Stack();
282 }
283
ef8e8623 284 // Check that we have the hits
285 if (!loader->TreeH() && loader->LoadHits()) {
286 AliError("Failed to load hits");
287 return;
288 }
289 TTree* hitsTree = loader->TreeH();
290 TBranch* hitsBranch = hitsTree->GetBranch(fFMD->GetName());
291 if (!hitsBranch) {
292 AliError("Failed to get hits branch in tree");
293 return;
294 }
295 // Check that we can make the output digits - This must come
296 // before AliFMD::SetBranchAddress
297 TTree* outTree = MakeOutputTree(loader);
298 if (!outTree) {
299 AliError("Failed to get output tree");
300 return;
301 }
302 AliFMDDebug(5, ("Output tree name for %s is '%s'",
303 (fOutput == kDigits ? "digits" : "sdigits"),
304 outTree->GetName()));
305 if (AliLog::GetDebugLevel("FMD","") >= 5) {
306 TFile* file = outTree->GetCurrentFile();
307 if (!file) {
308 AliWarning("Output tree has no file!");
309 }
310 else {
311 AliFMDDebug(5, ("Output tree file %s content:", file->GetName()));
312 file->ls();
313 }
314 }
315
316 // Set-up the branch addresses
317 fFMD->SetTreeAddress();
318
319 // Now sum all contributions in cache
320 SumContributions(hitsBranch);
321 loader->UnloadHits();
322
323 // And now digitize the hits
324 DigitizeHits();
325
326 // Write digits to tree
327 Int_t write = outTree->Fill();
83ad576a 328 AliFMDDebug(5, ("Wrote %d bytes to digit tree", write));
ef8e8623 329
330 // Store the digits
331 StoreDigits(loader);
332
333 }
334}
335
336//____________________________________________________________________
337TTree*
338AliFMDHitDigitizer::MakeOutputTree(AliLoader* loader)
339{
340 if (fOutput == kDigits)
341 return AliFMDBaseDigitizer::MakeOutputTree(loader);
342
343 AliFMDDebug(5, ("Making sdigits tree"));
344 loader->LoadSDigits("UPDATE"); // RECREATE");
345 TTree* out = loader->TreeS();
346 if (!out) loader->MakeTree("S");
347 out = loader->TreeS();
348 if (out) {
349 out->Reset();
350 fFMD->MakeBranch("S");
351 }
352 return out;
353}
354
355
356//____________________________________________________________________
357void
358AliFMDHitDigitizer::SumContributions(TBranch* hitsBranch)
359{
360 // Sum energy deposited contributions from each hit in a cache
361 // (fEdep).
362
363 // Clear array of deposited energies
364 fEdep.Reset();
365
366 // Get a list of hits from the FMD manager
367 AliFMDDebug(5, ("Get array of FMD hits"));
368 TClonesArray *fmdHits = fFMD->Hits();
369
370
371 // Get number of entries in the tree
372 AliFMDDebug(5, ("Get # of tracks"));
373 Int_t ntracks = Int_t(hitsBranch->GetEntries());
374 AliFMDDebug(5, ("We got %d tracks", ntracks));
375
376 Int_t read = 0;
377 // Loop over the tracks in the
378 for (Int_t track = 0; track < ntracks; track++) {
379 // Read in entry number `track'
380 read += hitsBranch->GetEntry(track);
83ad576a 381
ef8e8623 382 // Get the number of hits
383 Int_t nhits = fmdHits->GetEntries ();
384 for (Int_t hit = 0; hit < nhits; hit++) {
385 // Get the hit number `hit'
386 AliFMDHit* fmdHit =
387 static_cast<AliFMDHit*>(fmdHits->UncheckedAt(hit));
b2e6f0b0 388
389 // Ignore hits that arrive too late
390 if (fmdHit->Time() > fHoldTime) continue;
ef8e8623 391
b2e6f0b0 392
83ad576a 393 // Check if this is a primary particle
394 Bool_t isPrimary = kTRUE;
b2e6f0b0 395 Int_t trackno = -1;
83ad576a 396 if (fStack) {
b2e6f0b0 397 trackno = fmdHit->Track();
83ad576a 398 AliFMDDebug(10, ("Will get track # %d/%d from entry # %d",
399 trackno, fStack->GetNtrack(), track));
400 if (fStack->GetNtrack() < trackno) {
401 AliError(Form("Track number %d/%d out of bounds",
402 trackno, fStack->GetNtrack()));
403 continue;
404 }
b2e6f0b0 405#if 1
406 isPrimary = fStack->IsPhysicalPrimary(trackno);
407#else // This is our hand-crafted code. We use the ALICE definition
83ad576a 408 TParticle* part = fStack->Particle(trackno);
409 isPrimary = part->IsPrimary();
410 if (!isPrimary) {
411 // Extended testing of mother status - this is for Pythia6.
412 Int_t mother1 = part->GetFirstMother();
413 TParticle* mother = fStack->Particle(mother1);
414 if (!mother || mother->GetStatusCode() > 1)
415 isPrimary = kTRUE;
416 AliFMDDebug(15,
417 ("Track %d secondary, mother: %d - %s - status %d: %s",
418 trackno, mother1,
419 (mother ? "found" : "not found"),
420 (mother ? mother->GetStatusCode() : -1),
421 (isPrimary ? "primary" : "secondary")));
422 }
b2e6f0b0 423#endif
83ad576a 424 }
425
ef8e8623 426 // Extract parameters
427 AddContribution(fmdHit->Detector(),
428 fmdHit->Ring(),
429 fmdHit->Sector(),
430 fmdHit->Strip(),
83ad576a 431 fmdHit->Edep(),
b2e6f0b0 432 isPrimary,
433 trackno);
ef8e8623 434 } // hit loop
435 } // track loop
436 AliFMDDebug(5, ("Size of cache: %d bytes, read %d bytes",
437 sizeof(fEdep), read));
438}
439
440
441//____________________________________________________________________
442UShort_t
443AliFMDHitDigitizer::MakePedestal(UShort_t detector,
444 Char_t ring,
445 UShort_t sector,
446 UShort_t strip) const
447{
448 // Make a pedestal
449 if (fOutput == kSDigits) return 0;
450 return AliFMDBaseDigitizer::MakePedestal(detector, ring, sector, strip);
451}
452
453
454
455//____________________________________________________________________
456void
b2e6f0b0 457AliFMDHitDigitizer::AddDigit(UShort_t detector,
458 Char_t ring,
459 UShort_t sector,
460 UShort_t strip,
461 Float_t edep,
462 UShort_t count1,
463 Short_t count2,
464 Short_t count3,
465 Short_t count4,
466 UShort_t ntotal,
467 UShort_t nprim,
468 const TArrayI& refs) const
ef8e8623 469{
470 // Add a digit or summable digit
471 if (fOutput == kDigits) {
472 AliFMDBaseDigitizer::AddDigit(detector, ring, sector, strip, 0,
b2e6f0b0 473 count1, count2, count3, count4, 0, 0, refs);
83ad576a 474 return;
475 }
476 if (edep <= 0) {
477 AliFMDDebug(15, ("Digit edep = %f <= 0 for FMD%d%c[%2d,%3d]",
478 edep, detector, ring, sector, strip));
479 return;
480 }
481 if (count1 == 0 && count2 <= 0 && count3 <= 0 && count4 <= 0) {
482 AliFMDDebug(15, ("Digit counts = (%x,%x,%x,%x) <= 0 for FMD%d%c[%2d,%3d]",
483 count1, count2, count3, count4,
484 detector, ring, sector, strip));
ef8e8623 485 return;
486 }
83ad576a 487 AliFMDDebug(15, ("Adding digit for FMD%d%c[%2d,%3d] = (%x,%x,%x,%x) [%d/%d]",
488 detector, ring, sector, strip,
489 count1, count2, count3, count4, nprim, ntotal));
ef8e8623 490 fFMD->AddSDigitByFields(detector, ring, sector, strip, edep,
83ad576a 491 count1, count2, count3, count4,
b2e6f0b0 492 ntotal, nprim, refs);
ef8e8623 493}
494
495//____________________________________________________________________
496void
497AliFMDHitDigitizer::CheckDigit(AliFMDDigit* digit,
498 UShort_t nhits,
499 const TArrayI& counts)
500{
501 // Check that digit is consistent
502 AliFMDParameters* param = AliFMDParameters::Instance();
503 UShort_t det = digit->Detector();
504 Char_t ring = digit->Ring();
505 UShort_t sec = digit->Sector();
506 UShort_t str = digit->Strip();
507 Float_t mean = param->GetPedestal(det,ring,sec,str);
508 Float_t width = param->GetPedestalWidth(det,ring,sec,str);
509 UShort_t range = param->GetVA1MipRange();
510 UShort_t size = param->GetAltroChannelSize();
511 Int_t integral = counts[0];
512 if (counts[1] >= 0) integral += counts[1];
513 if (counts[2] >= 0) integral += counts[2];
514 if (counts[3] >= 0) integral += counts[3];
515 integral -= Int_t(mean + 2 * width);
516 if (integral < 0) integral = 0;
517
518 Float_t convF = Float_t(range) / size;
519 Float_t mips = integral * convF;
520 if (mips > Float_t(nhits) + .5 || mips < Float_t(nhits) - .5)
521 Warning("CheckDigit", "Digit -> %4.2f MIPS != %d +/- .5 hits",
522 mips, nhits);
523}
524
525//____________________________________________________________________
526void
527AliFMDHitDigitizer::StoreDigits(AliLoader* loader)
528{
529 if (fOutput == kDigits) {
530 AliFMDBaseDigitizer::StoreDigits(loader);
531 return;
532 }
533 AliFMDDebug(5, ("Storing %d sdigits", fFMD->SDigits()->GetEntries()));
534 // Write the digits to disk
535 loader->WriteSDigits("OVERWRITE");
536 loader->UnloadSDigits();
537 // Reset the digits in the AliFMD object
538 fFMD->ResetSDigits();
539}
540
541
542//____________________________________________________________________
543//
544// EOF
545//
546
547
548
549