[u/mrichter/AliRoot.git] / MONITOR / AliMonitorTrend.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
//  This class maintains a plot for the evolution of a value that is used    //
//  tomonitor the quality of the recorded data.                              //
//  The trendgram is created and filled by a sub class of AliMonitor.        //
//  It can be compared to a reference trendgram. For the comparison a        //
//  maximal deviation (in standard deviations) can be specified.             //
//  The bins where the maximal deviation is exceeded are drawn in red.       //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////


#include <TH1.h>
#include <TVirtualPad.h>
#include <TLine.h>

#include "AliLog.h"

#include "AliMonitorTrend.h"


ClassImp(AliMonitorTrend) 


Int_t AliMonitorTrend::fgIncSize = 10;


//_____________________________________________________________________________
AliMonitorTrend::AliMonitorTrend()
{
// default contructor

  fMin = fMax = 0;
  fHistoDraw = NULL;
  fRefMean = 0;
  fRefSigma = -1;
  fHistoCompare = NULL;
}

//_____________________________________________________________________________
AliMonitorTrend::AliMonitorTrend(const AliMonitorTrend& trend) :
  AliMonitorPlot(trend)
{
// copy constructor

  fLabel = trend.fLabel;
  fMin = trend.fMin;
  fMax = trend.fMax;
  trend.fData.Copy(fData);

  fHistoDraw = NULL;
  fRefMean = trend.fRefMean;
  fRefSigma = trend.fRefSigma;
  fHistoCompare = NULL;
}

//_____________________________________________________________________________
AliMonitorTrend& AliMonitorTrend::operator =(const AliMonitorTrend& trend)
{
// assignment operator

  AliMonitorPlot::operator =(trend);

  fLabel = trend.fLabel;
  fMin = trend.fMin;
  fMax = trend.fMax;
  trend.fData.Copy(fData);

  fHistoDraw = NULL;
  fRefMean = trend.fRefMean;
  fRefSigma = trend.fRefSigma;
  fHistoCompare = NULL;

  return *this;
}

//_____________________________________________________________________________
AliMonitorTrend::AliMonitorTrend(const char* name, const char* title,
		  const char* label, Double_t min, Double_t max) :
  AliMonitorPlot(name, title)
{
// create a monitor trend

  fLabel = label;
  fMin = min;
  fMax = max;

  fHistoDraw = NULL;
  fRefMean = fRefSigma = 0;
  fHistoCompare = NULL;
}

//_____________________________________________________________________________
AliMonitorTrend::~AliMonitorTrend()
{
// delete all histograms

  if (fHistoDraw) delete fHistoDraw;
  if (fHistoCompare) delete fHistoCompare;
}


//_____________________________________________________________________________
void AliMonitorTrend::SetReference(TH1* ref)
{
// set the reference trend for comparison

  Int_t n = ref->GetXaxis()->GetNbins();
  if (n <= 0) return;

  Double_t sum = 0;
  Double_t sum2 = 0;
  for (Int_t i = 1; i <= n; i++) {
    sum += ref->GetBinContent(i);
    sum2 += ref->GetBinContent(i) * ref->GetBinContent(i);
  }

  fRefMean = sum / n;
  fRefSigma = TMath::Sqrt(sum2 - sum*sum/n) / n;
}

//_____________________________________________________________________________
void AliMonitorTrend::SetReference(AliMonitorPlot* ref)
{
// set the reference trendgram for comparison

  if (!ref->InheritsFrom(AliMonitorTrend::Class())) return;
  fRefMean = ((AliMonitorTrend*)ref)->GetMean();
  fRefSigma = ((AliMonitorTrend*)ref)->GetSigma();
}


//_____________________________________________________________________________
void AliMonitorTrend::Fill(Double_t x)
{
// add a value to the monitor trend

  if (fNumberOfEvents >= fData.GetSize()) {
    fData.Set(fNumberOfEvents + fgIncSize);
  }
  fData[fNumberOfEvents] = x;
}


//_____________________________________________________________________________
void AliMonitorTrend::Update()
{
// update

  fNumberOfEvents++;
}

//_____________________________________________________________________________
void AliMonitorTrend::Add(AliMonitorPlot* plot)
{
// merge the given trend to this one

  if (!plot->InheritsFrom(AliMonitorTrend::Class())) return;
  AliMonitorTrend* trend = (AliMonitorTrend*) plot;

  Int_t numberOfEvents = fNumberOfEvents + trend->fNumberOfEvents;
  if (numberOfEvents >=  fData.GetSize()) {
    fData.Set(numberOfEvents + fgIncSize);
  }
  for (Int_t i = 0; i < trend->fNumberOfEvents; i++) {
    fData[fNumberOfEvents + i] = trend->fData[i];
  }
  fNumberOfEvents = numberOfEvents;
}

//_____________________________________________________________________________
void AliMonitorTrend::Reset()
{
// reset the monitor trend for a new run

  fData.Set(fgIncSize);
  if (fHistoDraw) delete fHistoDraw;
  fHistoDraw = NULL;
  if (fHistoCompare) delete fHistoCompare;
  fHistoCompare = NULL;
  fNumberOfEvents = 0;
}

//_____________________________________________________________________________
void AliMonitorTrend::ResetList()
{
// reset the the list of monitor histograms
// (not applicable for trend)

}


//_____________________________________________________________________________
Bool_t AliMonitorTrend::ComparePlot()
{
// compare the data trend to the reference
// if they deviate by more than fgThreshold standard deviations in a bin,
// this bin is set in fHistoCompare and kFALSE is returned
  
  if (fRefSigma < 0) return kTRUE;
  if (fgThreshold <= 0) return kTRUE;
  if (!fHistoDraw) {
    AliWarning("no data trend available for comparison\ncall DrawSum or DrawRaw before calling Compare");
    return kTRUE;
  }

  Int_t nBins = fHistoDraw->GetXaxis()->GetNbins();
  if (fHistoCompare) delete fHistoCompare;
  fHistoCompare = CreateHisto(nBins);
  fHistoCompare->Reset();
  fHistoCompare->SetOption("P");
  fHistoCompare->SetMarkerStyle(kFullCircle);
  fHistoCompare->SetFillStyle(0);
  Bool_t result = kTRUE;

  for (Int_t iBin = 1; iBin <= nBins; iBin++) {
    Double_t delta = TMath::Abs(fHistoDraw->GetBinContent(iBin) - fRefMean);
    if (delta > fgThreshold*fRefSigma) {
      fHistoCompare->SetBinContent(iBin, fHistoDraw->GetBinContent(iBin));
      result = kFALSE;
    }
  }

  return result;
}

//_____________________________________________________________________________
Bool_t AliMonitorTrend::GetEvent(Int_t)
{
// there is no single event trend

//  Info("GetEvent", "there is no trend for single events available");
  return kFALSE;
}

//_____________________________________________________________________________
Bool_t AliMonitorTrend::GetSum(Int_t number)
{
// get the monitor trend for the last  "number" events

  if (number > fNumberOfEvents) {
    AliError(Form("requested number of events (%d) exceeds range of available events (%d)\nusing last %d event(s)", 
	  number, fNumberOfEvents, fNumberOfEvents));
    number = fNumberOfEvents;
  }
  if (number <= 0) return kFALSE;

  if (fHistoDraw) delete fHistoDraw;
  if (fHistoCompare) delete fHistoCompare;
  fHistoCompare = NULL;

  fHistoDraw = CreateHisto(number);
  return kTRUE;
}

//_____________________________________________________________________________
Bool_t AliMonitorTrend::GetRun()
{
// get the monitor trend for all monitored events of the current run

  if (fHistoDraw) delete fHistoDraw;
  if (fHistoCompare) delete fHistoCompare;
  fHistoCompare = NULL;
  if (fNumberOfEvents <= 0) return kFALSE;

  fHistoDraw = CreateHisto(fNumberOfEvents);
  return kTRUE;
}

//_____________________________________________________________________________
void AliMonitorTrend::DrawPlot()
{
// draw the trendgrams

  fHistoDraw->SetMarkerColor(fgColorData);
  fHistoDraw->SetLineColor(fgColorData);
  fHistoDraw->SetLineWidth(2);
  fHistoDraw->DrawCopy();

  if ((fRefSigma > 0) && fgDrawRef) {
    if ((fRefMean+fRefSigma > fHistoDraw->GetMaximum()) && !(fMax > fMin)) {
      fHistoDraw->SetMaximum(fRefMean+fRefSigma * 1.1);
    }

    Double_t xMin = fHistoDraw->GetXaxis()->GetXmin();
    Double_t xMax = fHistoDraw->GetXaxis()->GetXmax();
    TLine* mean = new TLine(xMin, fRefMean, xMax, fRefMean);
    mean->SetLineColor(fgColorRef);
    mean->SetLineWidth(2);
    mean->Draw();
    TLine* high = new TLine(xMin, fRefMean+fRefSigma, 
			    xMax, fRefMean+fRefSigma);
    high->SetLineColor(fgColorRef);
    high->SetLineWidth(2);
    high->SetLineStyle(2);
    high->Draw();
    TLine* low = new TLine(xMin, fRefMean-fRefSigma, 
			   xMax, fRefMean-fRefSigma);
    low->SetLineColor(fgColorRef);
    low->SetLineWidth(2);
    low->SetLineStyle(2);
    low->Draw();

//    char option[256];
//    sprintf(option, "%sSAME", fHistoDraw->GetOption());
//    fHistoDraw->DrawCopy(option);

    if (fHistoCompare && (fgThreshold > 0)) {
      char option[256];
      sprintf(option, "%sSAME", fHistoCompare->GetOption());
      fHistoCompare->SetMarkerColor(fgColorCompare);
      fHistoCompare->SetLineColor(fgColorCompare);
      fHistoCompare->SetLineWidth(2);
      fHistoCompare->DrawCopy(option);
    }
  }

  gPad->Update();
}


//_____________________________________________________________________________
TH1* AliMonitorTrend::CreateHisto(Int_t nBins)
{
// create a histogram for a trend plot with the last nBin entries

  TH1* result = new TH1D(GetName(), GetTitle(), nBins, -nBins-0.5, -0.5);
  result->GetXaxis()->SetTitle("N_{event}");
  result->GetYaxis()->SetTitle(fLabel.Data());
  if (fMax > fMin) {
    result->SetMinimum(fMin);
    result->SetMaximum(fMax);
  }
  result->SetOption("L");

  Double_t sum = 0;
  Double_t sum2 = 0;
  for (Int_t i = 0; i < nBins; i++) {
    Double_t data = fData[fNumberOfEvents-1-i];
    sum += data;
    sum2 += data * data;
    result->SetBinContent(nBins-i, data);
  }
  Stat_t stats[4];
  stats[0] = nBins;
  stats[1] = nBins * nBins;
  stats[2] = sum;
  stats[3] = sum2;
  result->PutStats(stats);

  return result;
}

//_____________________________________________________________________________
Double_t AliMonitorTrend::GetMean() const
{
// get the mean value

  if (fNumberOfEvents <= 0) return 0;

  Double_t sum = 0;
  for (Int_t i = 0; i < fNumberOfEvents; i++) {
    sum += fData[i];
  }
  return sum / fNumberOfEvents;
}

//_____________________________________________________________________________
Double_t AliMonitorTrend::GetSigma() const
{
// get the rms value

  if (fNumberOfEvents <= 0) return 0;

  Double_t sum = 0;
  Double_t sum2 = 0;
  for (Int_t i = 0; i < fNumberOfEvents; i++) {
    sum += fData[i];
    sum2 += fData[i] * fData[i];
  }
  return TMath::Sqrt(sum2 - sum*sum/fNumberOfEvents) / fNumberOfEvents;
}
Commit	Line	Data
04fa961a	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, 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
	16	/* $Id$ */
	17
	18	///////////////////////////////////////////////////////////////////////////////
	19	// //
	20	// This class maintains a plot for the evolution of a value that is used //
	21	// tomonitor the quality of the recorded data. //
	22	// The trendgram is created and filled by a sub class of AliMonitor. //
	23	// It can be compared to a reference trendgram. For the comparison a //
	24	// maximal deviation (in standard deviations) can be specified. //
	25	// The bins where the maximal deviation is exceeded are drawn in red. //
	26	// //
	27	///////////////////////////////////////////////////////////////////////////////
	28
	29
c4bd737c	30	#include <TH1.h>
04fa961a	31	#include <TVirtualPad.h>
	32	#include <TLine.h>
	33
7ba8900c	34	#include "AliLog.h"
	35
	36	#include "AliMonitorTrend.h"
	37
04fa961a	38
	39	ClassImp(AliMonitorTrend)
	40
	41
	42	Int_t AliMonitorTrend::fgIncSize = 10;
	43
	44
	45	//_____________________________________________________________________________
	46	AliMonitorTrend::AliMonitorTrend()
	47	{
	48	// default contructor
	49
	50	fMin = fMax = 0;
	51	fHistoDraw = NULL;
	52	fRefMean = 0;
	53	fRefSigma = -1;
	54	fHistoCompare = NULL;
	55	}
	56
	57	//_____________________________________________________________________________
	58	AliMonitorTrend::AliMonitorTrend(const AliMonitorTrend& trend) :
	59	AliMonitorPlot(trend)
	60	{
	61	// copy constructor
	62
	63	fLabel = trend.fLabel;
	64	fMin = trend.fMin;
	65	fMax = trend.fMax;
	66	trend.fData.Copy(fData);
	67
	68	fHistoDraw = NULL;
	69	fRefMean = trend.fRefMean;
	70	fRefSigma = trend.fRefSigma;
	71	fHistoCompare = NULL;
	72	}
	73
c4bd737c	74	//_____________________________________________________________________________
	75	AliMonitorTrend& AliMonitorTrend::operator =(const AliMonitorTrend& trend)
	76	{
	77	// assignment operator
	78
	79	AliMonitorPlot::operator =(trend);
	80
	81	fLabel = trend.fLabel;
	82	fMin = trend.fMin;
	83	fMax = trend.fMax;
	84	trend.fData.Copy(fData);
	85
	86	fHistoDraw = NULL;
	87	fRefMean = trend.fRefMean;
	88	fRefSigma = trend.fRefSigma;
	89	fHistoCompare = NULL;
	90
	91	return *this;
	92	}
	93
04fa961a	94	//_____________________________________________________________________________
	95	AliMonitorTrend::AliMonitorTrend(const char* name, const char* title,
	96	const char* label, Double_t min, Double_t max) :
	97	AliMonitorPlot(name, title)
	98	{
	99	// create a monitor trend
	100
	101	fLabel = label;
	102	fMin = min;
	103	fMax = max;
	104
	105	fHistoDraw = NULL;
	106	fRefMean = fRefSigma = 0;
	107	fHistoCompare = NULL;
	108	}
	109
	110	//_____________________________________________________________________________
	111	AliMonitorTrend::~AliMonitorTrend()
	112	{
	113	// delete all histograms
	114
	115	if (fHistoDraw) delete fHistoDraw;
	116	if (fHistoCompare) delete fHistoCompare;
	117	}
	118
	119
	120	//_____________________________________________________________________________
	121	void AliMonitorTrend::SetReference(TH1* ref)
	122	{
	123	// set the reference trend for comparison
	124
	125	Int_t n = ref->GetXaxis()->GetNbins();
	126	if (n <= 0) return;
	127
	128	Double_t sum = 0;
	129	Double_t sum2 = 0;
	130	for (Int_t i = 1; i <= n; i++) {
	131	sum += ref->GetBinContent(i);
	132	sum2 += ref->GetBinContent(i) * ref->GetBinContent(i);
	133	}
	134
	135	fRefMean = sum / n;
	136	fRefSigma = TMath::Sqrt(sum2 - sum*sum/n) / n;
	137	}
	138
	139	//_____________________________________________________________________________
	140	void AliMonitorTrend::SetReference(AliMonitorPlot* ref)
	141	{
	142	// set the reference trendgram for comparison
	143
	144	if (!ref->InheritsFrom(AliMonitorTrend::Class())) return;
	145	fRefMean = ((AliMonitorTrend*)ref)->GetMean();
	146	fRefSigma = ((AliMonitorTrend*)ref)->GetSigma();
	147	}
	148
	149
	150	//_____________________________________________________________________________
	151	void AliMonitorTrend::Fill(Double_t x)
	152	{
	153	// add a value to the monitor trend
	154
	155	if (fNumberOfEvents >= fData.GetSize()) {
	156	fData.Set(fNumberOfEvents + fgIncSize);
	157	}
158	fData[fNumberOfEvents] = x;
159	}
160
161
162	//_____________________________________________________________________________
163	void AliMonitorTrend::Update()
164	{
165	// update
166
167	fNumberOfEvents++;
168	}
169
170	//_____________________________________________________________________________
171	void AliMonitorTrend::Add(AliMonitorPlot* plot)
172	{
173	// merge the given trend to this one
174
175	if (!plot->InheritsFrom(AliMonitorTrend::Class())) return;
176	AliMonitorTrend* trend = (AliMonitorTrend*) plot;
177
178	Int_t numberOfEvents = fNumberOfEvents + trend->fNumberOfEvents;
179	if (numberOfEvents >= fData.GetSize()) {
180	fData.Set(numberOfEvents + fgIncSize);
181	}
182	for (Int_t i = 0; i < trend->fNumberOfEvents; i++) {
183	fData[fNumberOfEvents + i] = trend->fData[i];
184	}
185	fNumberOfEvents = numberOfEvents;
186	}
187
188	//_____________________________________________________________________________
189	void AliMonitorTrend::Reset()
190	{
191	// reset the monitor trend for a new run
192
193	fData.Set(fgIncSize);
194	if (fHistoDraw) delete fHistoDraw;
195	fHistoDraw = NULL;
196	if (fHistoCompare) delete fHistoCompare;
197	fHistoCompare = NULL;
198	fNumberOfEvents = 0;
199	}
200
201	//_____________________________________________________________________________
202	void AliMonitorTrend::ResetList()
203	{
204	// reset the the list of monitor histograms
205	// (not applicable for trend)
206
207	}
208
209
210	//_____________________________________________________________________________
211	Bool_t AliMonitorTrend::ComparePlot()
212	{
213	// compare the data trend to the reference
214	// if they deviate by more than fgThreshold standard deviations in a bin,
215	// this bin is set in fHistoCompare and kFALSE is returned
216
217	if (fRefSigma < 0) return kTRUE;
218	if (fgThreshold <= 0) return kTRUE;
219	if (!fHistoDraw) {
7ba8900c	220	AliWarning("no data trend available for comparison\ncall DrawSum or DrawRaw before calling Compare");
04fa961a	221	return kTRUE;
	222	}
	223
	224	Int_t nBins = fHistoDraw->GetXaxis()->GetNbins();
	225	if (fHistoCompare) delete fHistoCompare;
	226	fHistoCompare = CreateHisto(nBins);
	227	fHistoCompare->Reset();
	228	fHistoCompare->SetOption("P");
	229	fHistoCompare->SetMarkerStyle(kFullCircle);
	230	fHistoCompare->SetFillStyle(0);
	231	Bool_t result = kTRUE;
	232
	233	for (Int_t iBin = 1; iBin <= nBins; iBin++) {
	234	Double_t delta = TMath::Abs(fHistoDraw->GetBinContent(iBin) - fRefMean);
	235	if (delta > fgThreshold*fRefSigma) {
	236	fHistoCompare->SetBinContent(iBin, fHistoDraw->GetBinContent(iBin));
	237	result = kFALSE;
	238	}
	239	}
	240
	241	return result;
	242	}
	243
	244	//_____________________________________________________________________________
	245	Bool_t AliMonitorTrend::GetEvent(Int_t)
	246	{
	247	// there is no single event trend
	248
97d6eb66	249	// Info("GetEvent", "there is no trend for single events available");
04fa961a	250	return kFALSE;
	251	}
	252
	253	//_____________________________________________________________________________
	254	Bool_t AliMonitorTrend::GetSum(Int_t number)
	255	{
	256	// get the monitor trend for the last "number" events
	257
	258	if (number > fNumberOfEvents) {
7ba8900c	259	AliError(Form("requested number of events (%d) exceeds range of available events (%d)\nusing last %d event(s)",
7ba8900c	260	number, fNumberOfEvents, fNumberOfEvents));
04fa961a	261	number = fNumberOfEvents;
	262	}
	263	if (number <= 0) return kFALSE;
	264
	265	if (fHistoDraw) delete fHistoDraw;
	266	if (fHistoCompare) delete fHistoCompare;
	267	fHistoCompare = NULL;
	268
	269	fHistoDraw = CreateHisto(number);
	270	return kTRUE;
	271	}
	272
	273	//_____________________________________________________________________________
	274	Bool_t AliMonitorTrend::GetRun()
	275	{
	276	// get the monitor trend for all monitored events of the current run
	277
	278	if (fHistoDraw) delete fHistoDraw;
	279	if (fHistoCompare) delete fHistoCompare;
	280	fHistoCompare = NULL;
	281	if (fNumberOfEvents <= 0) return kFALSE;
	282
	283	fHistoDraw = CreateHisto(fNumberOfEvents);
	284	return kTRUE;
	285	}
	286
	287	//_____________________________________________________________________________
	288	void AliMonitorTrend::DrawPlot()
	289	{
	290	// draw the trendgrams
	291
	292	fHistoDraw->SetMarkerColor(fgColorData);
	293	fHistoDraw->SetLineColor(fgColorData);
	294	fHistoDraw->SetLineWidth(2);
	295	fHistoDraw->DrawCopy();
	296
	297	if ((fRefSigma > 0) && fgDrawRef) {
	298	if ((fRefMean+fRefSigma > fHistoDraw->GetMaximum()) && !(fMax > fMin)) {
	299	fHistoDraw->SetMaximum(fRefMean+fRefSigma * 1.1);
	300	}
	301
	302	Double_t xMin = fHistoDraw->GetXaxis()->GetXmin();
	303	Double_t xMax = fHistoDraw->GetXaxis()->GetXmax();
	304	TLine* mean = new TLine(xMin, fRefMean, xMax, fRefMean);
	305	mean->SetLineColor(fgColorRef);
	306	mean->SetLineWidth(2);
	307	mean->Draw();
	308	TLine* high = new TLine(xMin, fRefMean+fRefSigma,
	309	xMax, fRefMean+fRefSigma);
	310	high->SetLineColor(fgColorRef);
	311	high->SetLineWidth(2);
	312	high->SetLineStyle(2);
	313	high->Draw();
	314	TLine* low = new TLine(xMin, fRefMean-fRefSigma,
	315	xMax, fRefMean-fRefSigma);
	316	low->SetLineColor(fgColorRef);
	317	low->SetLineWidth(2);
	318	low->SetLineStyle(2);
	319	low->Draw();
	320
	321	// char option[256];
	322	// sprintf(option, "%sSAME", fHistoDraw->GetOption());
	323	// fHistoDraw->DrawCopy(option);
	324
325	if (fHistoCompare && (fgThreshold > 0)) {
326	char option[256];
327	sprintf(option, "%sSAME", fHistoCompare->GetOption());
328	fHistoCompare->SetMarkerColor(fgColorCompare);
329	fHistoCompare->SetLineColor(fgColorCompare);
330	fHistoCompare->SetLineWidth(2);
331	fHistoCompare->DrawCopy(option);
332	}
333	}
334
335	gPad->Update();
336	}
337
338
339	//_____________________________________________________________________________
340	TH1* AliMonitorTrend::CreateHisto(Int_t nBins)
341	{
342	// create a histogram for a trend plot with the last nBin entries
343
344	TH1* result = new TH1D(GetName(), GetTitle(), nBins, -nBins-0.5, -0.5);
345	result->GetXaxis()->SetTitle("N_{event}");
346	result->GetYaxis()->SetTitle(fLabel.Data());
347	if (fMax > fMin) {
348	result->SetMinimum(fMin);
349	result->SetMaximum(fMax);
350	}
351	result->SetOption("L");
352
353	Double_t sum = 0;
354	Double_t sum2 = 0;
355	for (Int_t i = 0; i < nBins; i++) {
356	Double_t data = fData[fNumberOfEvents-1-i];
357	sum += data;
358	sum2 += data * data;
359	result->SetBinContent(nBins-i, data);
360	}
361	Stat_t stats[4];
362	stats[0] = nBins;
363	stats[1] = nBins * nBins;
364	stats[2] = sum;
365	stats[3] = sum2;
366	result->PutStats(stats);
367
368	return result;
369	}
370
371	//_____________________________________________________________________________
c4bd737c	372	Double_t AliMonitorTrend::GetMean() const
04fa961a	373	{
	374	// get the mean value
	375
	376	if (fNumberOfEvents <= 0) return 0;
	377
	378	Double_t sum = 0;
	379	for (Int_t i = 0; i < fNumberOfEvents; i++) {
	380	sum += fData[i];
	381	}
	382	return sum / fNumberOfEvents;
	383	}
	384
	385	//_____________________________________________________________________________
c4bd737c	386	Double_t AliMonitorTrend::GetSigma() const
04fa961a	387	{
	388	// get the rms value
	389
	390	if (fNumberOfEvents <= 0) return 0;
	391
	392	Double_t sum = 0;
	393	Double_t sum2 = 0;
	394	for (Int_t i = 0; i < fNumberOfEvents; i++) {
	395	sum += fData[i];
	396	sum2 += fData[i] * fData[i];
	397	}
	398	return TMath::Sqrt(sum2 - sum*sum/fNumberOfEvents) / fNumberOfEvents;
	399	}
	400