Compatibility with the trunk of ROOT
[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)
133f1578 214 : AliFMDBaseDigitizer("FMD", (output == kDigits ?
ef8e8623 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//____________________________________________________________________
09b6c804 225AliFMDHitDigitizer&
226AliFMDHitDigitizer::operator=(const AliFMDHitDigitizer& o)
227{
228 /**
229 * Assignment operator
230 *
231 * @param o Object to assign from
232 * @return Reference to this
233 */
d015ecfe 234 if (&o == this) return *this;
09b6c804 235 AliFMDBaseDigitizer::operator=(o);
236 fHoldTime = o.fHoldTime;
237 fOutput = o.fOutput;
238 fStack = o.fStack;
239 return *this;
240}
241
242//____________________________________________________________________
ef8e8623 243void
f21fc003 244AliFMDHitDigitizer::Digitize(Option_t* /*option*/)
ef8e8623 245{
246 // Run this digitizer
247 // Get an inititialize parameter manager
248 AliFMDParameters::Instance()->Init();
249 if (AliLog::GetDebugLevel("FMD","") >= 10)
250 AliFMDParameters::Instance()->Print("ALL");
251
252 // Get loader, and ask it to read in the hits
253 AliLoader* loader = fFMD->GetLoader();
254 if (!loader) {
255 AliError("Failed to get loader from detector object");
256 return;
257 }
258 loader->LoadHits("READ");
259
260 // Get the run loader
261 AliRunLoader* runLoader = loader->GetRunLoader();
262 if (!runLoader) {
263 AliError("Failed to get run loader from loader");
264 return;
265 }
266
267 // Now loop over events
268 Int_t nEvents = runLoader->GetNumberOfEvents();
269 for (Int_t event = 0; event < nEvents; event++) {
270 // Get the current event folder.
271 TFolder* folder = loader->GetEventFolder();
272 if (!folder) {
273 AliError("Failed to get event folder from loader");
274 return;
275 }
276
277 // Get the run-loader of this event.
278 const char* loaderName = AliRunLoader::GetRunLoaderName();
279 AliRunLoader* thisLoader =
280 static_cast<AliRunLoader*>(folder->FindObject(loaderName));
281 if (!thisLoader) {
282 AliError(Form("Failed to get loader '%s' from event folder", loaderName));
283 return;
284 }
285
286 // Read in the event
8d00dfa3 287 AliFMDDebug(1, ("Now digitizing (Hits->%s) event # %d",
ef8e8623 288 (fOutput == kDigits ? "digits" : "sdigits"), event));
289 thisLoader->GetEvent(event);
290
83ad576a 291 // Load kinematics to get primary information for SDigits
292 fStack = 0;
293 if (fOutput == kSDigits) {
294 if (thisLoader->LoadKinematics("READ")) {
295 AliError("Failed to get kinematics from event loader");
296 return;
297 }
298 AliFMDDebug(5, ("Loading stack of kinematics"));
299 fStack = thisLoader->Stack();
300 }
301
ef8e8623 302 // Check that we have the hits
303 if (!loader->TreeH() && loader->LoadHits()) {
304 AliError("Failed to load hits");
305 return;
306 }
307 TTree* hitsTree = loader->TreeH();
308 TBranch* hitsBranch = hitsTree->GetBranch(fFMD->GetName());
309 if (!hitsBranch) {
310 AliError("Failed to get hits branch in tree");
311 return;
312 }
313 // Check that we can make the output digits - This must come
314 // before AliFMD::SetBranchAddress
315 TTree* outTree = MakeOutputTree(loader);
316 if (!outTree) {
317 AliError("Failed to get output tree");
318 return;
319 }
320 AliFMDDebug(5, ("Output tree name for %s is '%s'",
321 (fOutput == kDigits ? "digits" : "sdigits"),
322 outTree->GetName()));
323 if (AliLog::GetDebugLevel("FMD","") >= 5) {
324 TFile* file = outTree->GetCurrentFile();
325 if (!file) {
326 AliWarning("Output tree has no file!");
327 }
328 else {
329 AliFMDDebug(5, ("Output tree file %s content:", file->GetName()));
330 file->ls();
331 }
332 }
333
334 // Set-up the branch addresses
335 fFMD->SetTreeAddress();
336
337 // Now sum all contributions in cache
338 SumContributions(hitsBranch);
339 loader->UnloadHits();
340
341 // And now digitize the hits
342 DigitizeHits();
343
344 // Write digits to tree
345 Int_t write = outTree->Fill();
83ad576a 346 AliFMDDebug(5, ("Wrote %d bytes to digit tree", write));
ef8e8623 347
348 // Store the digits
349 StoreDigits(loader);
350
351 }
352}
353
354//____________________________________________________________________
355TTree*
356AliFMDHitDigitizer::MakeOutputTree(AliLoader* loader)
357{
09b6c804 358 /**
359 * Make the output tree using the passed loader
360 *
361 * @param loader
362 * @return The generated tree.
363 */
ef8e8623 364 if (fOutput == kDigits)
365 return AliFMDBaseDigitizer::MakeOutputTree(loader);
366
367 AliFMDDebug(5, ("Making sdigits tree"));
368 loader->LoadSDigits("UPDATE"); // RECREATE");
369 TTree* out = loader->TreeS();
370 if (!out) loader->MakeTree("S");
371 out = loader->TreeS();
372 if (out) {
373 out->Reset();
374 fFMD->MakeBranch("S");
375 }
376 return out;
377}
378
379
380//____________________________________________________________________
381void
382AliFMDHitDigitizer::SumContributions(TBranch* hitsBranch)
383{
384 // Sum energy deposited contributions from each hit in a cache
385 // (fEdep).
386
387 // Clear array of deposited energies
388 fEdep.Reset();
389
390 // Get a list of hits from the FMD manager
391 AliFMDDebug(5, ("Get array of FMD hits"));
392 TClonesArray *fmdHits = fFMD->Hits();
393
394
395 // Get number of entries in the tree
396 AliFMDDebug(5, ("Get # of tracks"));
397 Int_t ntracks = Int_t(hitsBranch->GetEntries());
398 AliFMDDebug(5, ("We got %d tracks", ntracks));
399
400 Int_t read = 0;
401 // Loop over the tracks in the
402 for (Int_t track = 0; track < ntracks; track++) {
403 // Read in entry number `track'
404 read += hitsBranch->GetEntry(track);
83ad576a 405
ef8e8623 406 // Get the number of hits
407 Int_t nhits = fmdHits->GetEntries ();
408 for (Int_t hit = 0; hit < nhits; hit++) {
409 // Get the hit number `hit'
410 AliFMDHit* fmdHit =
411 static_cast<AliFMDHit*>(fmdHits->UncheckedAt(hit));
b2e6f0b0 412
413 // Ignore hits that arrive too late
414 if (fmdHit->Time() > fHoldTime) continue;
ef8e8623 415
b2e6f0b0 416
83ad576a 417 // Check if this is a primary particle
418 Bool_t isPrimary = kTRUE;
b2e6f0b0 419 Int_t trackno = -1;
83ad576a 420 if (fStack) {
b2e6f0b0 421 trackno = fmdHit->Track();
83ad576a 422 AliFMDDebug(10, ("Will get track # %d/%d from entry # %d",
423 trackno, fStack->GetNtrack(), track));
424 if (fStack->GetNtrack() < trackno) {
425 AliError(Form("Track number %d/%d out of bounds",
426 trackno, fStack->GetNtrack()));
427 continue;
428 }
b2e6f0b0 429#if 1
430 isPrimary = fStack->IsPhysicalPrimary(trackno);
431#else // This is our hand-crafted code. We use the ALICE definition
83ad576a 432 TParticle* part = fStack->Particle(trackno);
433 isPrimary = part->IsPrimary();
434 if (!isPrimary) {
435 // Extended testing of mother status - this is for Pythia6.
436 Int_t mother1 = part->GetFirstMother();
437 TParticle* mother = fStack->Particle(mother1);
438 if (!mother || mother->GetStatusCode() > 1)
439 isPrimary = kTRUE;
440 AliFMDDebug(15,
441 ("Track %d secondary, mother: %d - %s - status %d: %s",
442 trackno, mother1,
443 (mother ? "found" : "not found"),
444 (mother ? mother->GetStatusCode() : -1),
445 (isPrimary ? "primary" : "secondary")));
446 }
b2e6f0b0 447#endif
83ad576a 448 }
449
ef8e8623 450 // Extract parameters
8d00dfa3 451 AliFMDDebug(15,("Adding contribution %7.5f for FMD%d%c[%2d,%3d] "
452 " for trackno %6d (%s)",
453 fmdHit->Edep(),
454 fmdHit->Detector(),
455 fmdHit->Ring(),
456 fmdHit->Sector(),
457 fmdHit->Strip(),
458 trackno,
459 (isPrimary ? "primary" : "secondary")));
ef8e8623 460 AddContribution(fmdHit->Detector(),
461 fmdHit->Ring(),
462 fmdHit->Sector(),
463 fmdHit->Strip(),
83ad576a 464 fmdHit->Edep(),
b2e6f0b0 465 isPrimary,
faf80567 466 1,
467 &trackno);
ef8e8623 468 } // hit loop
469 } // track loop
470 AliFMDDebug(5, ("Size of cache: %d bytes, read %d bytes",
a828379a 471 int(sizeof(fEdep)), read));
ef8e8623 472}
473
474
475//____________________________________________________________________
476UShort_t
477AliFMDHitDigitizer::MakePedestal(UShort_t detector,
478 Char_t ring,
479 UShort_t sector,
480 UShort_t strip) const
481{
482 // Make a pedestal
483 if (fOutput == kSDigits) return 0;
484 return AliFMDBaseDigitizer::MakePedestal(detector, ring, sector, strip);
485}
486
487
488
489//____________________________________________________________________
490void
b2e6f0b0 491AliFMDHitDigitizer::AddDigit(UShort_t detector,
492 Char_t ring,
493 UShort_t sector,
494 UShort_t strip,
495 Float_t edep,
496 UShort_t count1,
497 Short_t count2,
498 Short_t count3,
499 Short_t count4,
500 UShort_t ntotal,
501 UShort_t nprim,
502 const TArrayI& refs) const
ef8e8623 503{
504 // Add a digit or summable digit
505 if (fOutput == kDigits) {
faf80567 506 AliFMDDebug(15,("Adding digit for FMD%d%c[%2d,%3d] = (%x,%x,%x,%x)",
507 detector, ring, sector, strip,
508 count1, count2, count3, count4));
ef8e8623 509 AliFMDBaseDigitizer::AddDigit(detector, ring, sector, strip, 0,
8d00dfa3 510 count1, count2, count3, count4,
511 ntotal, nprim, refs);
83ad576a 512 return;
513 }
514 if (edep <= 0) {
515 AliFMDDebug(15, ("Digit edep = %f <= 0 for FMD%d%c[%2d,%3d]",
516 edep, detector, ring, sector, strip));
517 return;
518 }
519 if (count1 == 0 && count2 <= 0 && count3 <= 0 && count4 <= 0) {
520 AliFMDDebug(15, ("Digit counts = (%x,%x,%x,%x) <= 0 for FMD%d%c[%2d,%3d]",
521 count1, count2, count3, count4,
522 detector, ring, sector, strip));
ef8e8623 523 return;
524 }
faf80567 525 AliFMDDebug(15, ("Adding sdigit for FMD%d%c[%2d,%3d] = "
526 "(%x,%x,%x,%x) [%d/%d] %d",
83ad576a 527 detector, ring, sector, strip,
faf80567 528 count1, count2, count3, count4, nprim, ntotal, refs.fN));
ef8e8623 529 fFMD->AddSDigitByFields(detector, ring, sector, strip, edep,
83ad576a 530 count1, count2, count3, count4,
8d00dfa3 531 ntotal, nprim, fStoreTrackRefs ? refs.fArray : 0);
2180cab3 532 if (fStoreTrackRefs && nprim > 3) fIgnoredLabels += nprim - 3;
ef8e8623 533}
534
535//____________________________________________________________________
536void
537AliFMDHitDigitizer::CheckDigit(AliFMDDigit* digit,
538 UShort_t nhits,
539 const TArrayI& counts)
540{
541 // Check that digit is consistent
542 AliFMDParameters* param = AliFMDParameters::Instance();
543 UShort_t det = digit->Detector();
544 Char_t ring = digit->Ring();
545 UShort_t sec = digit->Sector();
546 UShort_t str = digit->Strip();
547 Float_t mean = param->GetPedestal(det,ring,sec,str);
548 Float_t width = param->GetPedestalWidth(det,ring,sec,str);
549 UShort_t range = param->GetVA1MipRange();
550 UShort_t size = param->GetAltroChannelSize();
551 Int_t integral = counts[0];
552 if (counts[1] >= 0) integral += counts[1];
553 if (counts[2] >= 0) integral += counts[2];
554 if (counts[3] >= 0) integral += counts[3];
555 integral -= Int_t(mean + 2 * width);
556 if (integral < 0) integral = 0;
557
558 Float_t convF = Float_t(range) / size;
559 Float_t mips = integral * convF;
560 if (mips > Float_t(nhits) + .5 || mips < Float_t(nhits) - .5)
561 Warning("CheckDigit", "Digit -> %4.2f MIPS != %d +/- .5 hits",
562 mips, nhits);
563}
564
565//____________________________________________________________________
566void
aa24869b 567AliFMDHitDigitizer::StoreDigits(const AliLoader* loader)
ef8e8623 568{
09b6c804 569 /**
570 * Store the data using the loader
571 *
572 * @param loader The loader
573 */
ef8e8623 574 if (fOutput == kDigits) {
575 AliFMDBaseDigitizer::StoreDigits(loader);
576 return;
577 }
578 AliFMDDebug(5, ("Storing %d sdigits", fFMD->SDigits()->GetEntries()));
579 // Write the digits to disk
580 loader->WriteSDigits("OVERWRITE");
581 loader->UnloadSDigits();
582 // Reset the digits in the AliFMD object
583 fFMD->ResetSDigits();
584}
585
586
587//____________________________________________________________________
588//
589// EOF
590//
591
592
593
594