Several fixes (the Make-Federico-Happy-Commit):
[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>
202#include <TFile.h>
203
204//====================================================================
205ClassImp(AliFMDHitDigitizer)
206#if 0
207;
208#endif
209
210//____________________________________________________________________
211AliFMDHitDigitizer::AliFMDHitDigitizer(AliFMD* fmd, Output_t output)
212 : AliFMDBaseDigitizer("FMD", (fOutput == kDigits ?
213 "FMD Hit->Digit digitizer" :
214 "FMD Hit->SDigit digitizer")),
215 fOutput(output)
216{
217 fFMD = fmd;
218}
219
220//____________________________________________________________________
221void
222AliFMDHitDigitizer::Exec(Option_t* /*option*/)
223{
224 // Run this digitizer
225 // Get an inititialize parameter manager
226 AliFMDParameters::Instance()->Init();
227 if (AliLog::GetDebugLevel("FMD","") >= 10)
228 AliFMDParameters::Instance()->Print("ALL");
229
230 // Get loader, and ask it to read in the hits
231 AliLoader* loader = fFMD->GetLoader();
232 if (!loader) {
233 AliError("Failed to get loader from detector object");
234 return;
235 }
236 loader->LoadHits("READ");
237
238 // Get the run loader
239 AliRunLoader* runLoader = loader->GetRunLoader();
240 if (!runLoader) {
241 AliError("Failed to get run loader from loader");
242 return;
243 }
244
245 // Now loop over events
246 Int_t nEvents = runLoader->GetNumberOfEvents();
247 for (Int_t event = 0; event < nEvents; event++) {
248 // Get the current event folder.
249 TFolder* folder = loader->GetEventFolder();
250 if (!folder) {
251 AliError("Failed to get event folder from loader");
252 return;
253 }
254
255 // Get the run-loader of this event.
256 const char* loaderName = AliRunLoader::GetRunLoaderName();
257 AliRunLoader* thisLoader =
258 static_cast<AliRunLoader*>(folder->FindObject(loaderName));
259 if (!thisLoader) {
260 AliError(Form("Failed to get loader '%s' from event folder", loaderName));
261 return;
262 }
263
264 // Read in the event
265 AliFMDDebug(5, ("Now digitizing (Hits->%s) event # %d",
266 (fOutput == kDigits ? "digits" : "sdigits"), event));
267 thisLoader->GetEvent(event);
268
269 // Check that we have the hits
270 if (!loader->TreeH() && loader->LoadHits()) {
271 AliError("Failed to load hits");
272 return;
273 }
274 TTree* hitsTree = loader->TreeH();
275 TBranch* hitsBranch = hitsTree->GetBranch(fFMD->GetName());
276 if (!hitsBranch) {
277 AliError("Failed to get hits branch in tree");
278 return;
279 }
280 // Check that we can make the output digits - This must come
281 // before AliFMD::SetBranchAddress
282 TTree* outTree = MakeOutputTree(loader);
283 if (!outTree) {
284 AliError("Failed to get output tree");
285 return;
286 }
287 AliFMDDebug(5, ("Output tree name for %s is '%s'",
288 (fOutput == kDigits ? "digits" : "sdigits"),
289 outTree->GetName()));
290 if (AliLog::GetDebugLevel("FMD","") >= 5) {
291 TFile* file = outTree->GetCurrentFile();
292 if (!file) {
293 AliWarning("Output tree has no file!");
294 }
295 else {
296 AliFMDDebug(5, ("Output tree file %s content:", file->GetName()));
297 file->ls();
298 }
299 }
300
301 // Set-up the branch addresses
302 fFMD->SetTreeAddress();
303
304 // Now sum all contributions in cache
305 SumContributions(hitsBranch);
306 loader->UnloadHits();
307
308 // And now digitize the hits
309 DigitizeHits();
310
311 // Write digits to tree
312 Int_t write = outTree->Fill();
313 AliFMDDebug(1, ("Wrote %d bytes to digit tree", write));
314
315 // Store the digits
316 StoreDigits(loader);
317
318 }
319}
320
321//____________________________________________________________________
322TTree*
323AliFMDHitDigitizer::MakeOutputTree(AliLoader* loader)
324{
325 if (fOutput == kDigits)
326 return AliFMDBaseDigitizer::MakeOutputTree(loader);
327
328 AliFMDDebug(5, ("Making sdigits tree"));
329 loader->LoadSDigits("UPDATE"); // RECREATE");
330 TTree* out = loader->TreeS();
331 if (!out) loader->MakeTree("S");
332 out = loader->TreeS();
333 if (out) {
334 out->Reset();
335 fFMD->MakeBranch("S");
336 }
337 return out;
338}
339
340
341//____________________________________________________________________
342void
343AliFMDHitDigitizer::SumContributions(TBranch* hitsBranch)
344{
345 // Sum energy deposited contributions from each hit in a cache
346 // (fEdep).
347
348 // Clear array of deposited energies
349 fEdep.Reset();
350
351 // Get a list of hits from the FMD manager
352 AliFMDDebug(5, ("Get array of FMD hits"));
353 TClonesArray *fmdHits = fFMD->Hits();
354
355
356 // Get number of entries in the tree
357 AliFMDDebug(5, ("Get # of tracks"));
358 Int_t ntracks = Int_t(hitsBranch->GetEntries());
359 AliFMDDebug(5, ("We got %d tracks", ntracks));
360
361 Int_t read = 0;
362 // Loop over the tracks in the
363 for (Int_t track = 0; track < ntracks; track++) {
364 // Read in entry number `track'
365 read += hitsBranch->GetEntry(track);
366
367 // Get the number of hits
368 Int_t nhits = fmdHits->GetEntries ();
369 for (Int_t hit = 0; hit < nhits; hit++) {
370 // Get the hit number `hit'
371 AliFMDHit* fmdHit =
372 static_cast<AliFMDHit*>(fmdHits->UncheckedAt(hit));
373
374 // Extract parameters
375 AddContribution(fmdHit->Detector(),
376 fmdHit->Ring(),
377 fmdHit->Sector(),
378 fmdHit->Strip(),
379 fmdHit->Edep());
380 } // hit loop
381 } // track loop
382 AliFMDDebug(5, ("Size of cache: %d bytes, read %d bytes",
383 sizeof(fEdep), read));
384}
385
386
387//____________________________________________________________________
388UShort_t
389AliFMDHitDigitizer::MakePedestal(UShort_t detector,
390 Char_t ring,
391 UShort_t sector,
392 UShort_t strip) const
393{
394 // Make a pedestal
395 if (fOutput == kSDigits) return 0;
396 return AliFMDBaseDigitizer::MakePedestal(detector, ring, sector, strip);
397}
398
399
400
401//____________________________________________________________________
402void
403AliFMDHitDigitizer::AddDigit(UShort_t detector,
404 Char_t ring,
405 UShort_t sector,
406 UShort_t strip,
407 Float_t edep,
408 UShort_t count1,
409 Short_t count2,
410 Short_t count3,
411 Short_t count4) const
412{
413 // Add a digit or summable digit
414 if (fOutput == kDigits) {
415 AliFMDBaseDigitizer::AddDigit(detector, ring, sector, strip, 0,
416 count1, count2, count3, count4);
417 return;
418 }
419 if (edep <= 0) return;
420 if (count1 == 0 && count2 <= 0 && count3 <= 0 && count4 <= 0) return;
421 fFMD->AddSDigitByFields(detector, ring, sector, strip, edep,
422 count1, count2, count3, count4);
423}
424
425//____________________________________________________________________
426void
427AliFMDHitDigitizer::CheckDigit(AliFMDDigit* digit,
428 UShort_t nhits,
429 const TArrayI& counts)
430{
431 // Check that digit is consistent
432 AliFMDParameters* param = AliFMDParameters::Instance();
433 UShort_t det = digit->Detector();
434 Char_t ring = digit->Ring();
435 UShort_t sec = digit->Sector();
436 UShort_t str = digit->Strip();
437 Float_t mean = param->GetPedestal(det,ring,sec,str);
438 Float_t width = param->GetPedestalWidth(det,ring,sec,str);
439 UShort_t range = param->GetVA1MipRange();
440 UShort_t size = param->GetAltroChannelSize();
441 Int_t integral = counts[0];
442 if (counts[1] >= 0) integral += counts[1];
443 if (counts[2] >= 0) integral += counts[2];
444 if (counts[3] >= 0) integral += counts[3];
445 integral -= Int_t(mean + 2 * width);
446 if (integral < 0) integral = 0;
447
448 Float_t convF = Float_t(range) / size;
449 Float_t mips = integral * convF;
450 if (mips > Float_t(nhits) + .5 || mips < Float_t(nhits) - .5)
451 Warning("CheckDigit", "Digit -> %4.2f MIPS != %d +/- .5 hits",
452 mips, nhits);
453}
454
455//____________________________________________________________________
456void
457AliFMDHitDigitizer::StoreDigits(AliLoader* loader)
458{
459 if (fOutput == kDigits) {
460 AliFMDBaseDigitizer::StoreDigits(loader);
461 return;
462 }
463 AliFMDDebug(5, ("Storing %d sdigits", fFMD->SDigits()->GetEntries()));
464 // Write the digits to disk
465 loader->WriteSDigits("OVERWRITE");
466 loader->UnloadSDigits();
467 // Reset the digits in the AliFMD object
468 fFMD->ResetSDigits();
469}
470
471
472//____________________________________________________________________
473//
474// EOF
475//
476
477
478
479