Plotting Utility Functions

Functions
TH1D	MaCh3Plotting::TGraphToTH1D (TGraph graph, std::string newName="", std::string newTitle="")
	This handy little function lets you interpret a TGraph as a TH1D.
std::vector< std::vector< double > >	MaCh3Plotting::TGraphToVector (TGraph graph)
	This handy little function lets you interpret a TGraph as a vector containing the same data.
std::vector< std::vector< double > >	MaCh3Plotting::TGraphToVector (TGraph2D graph)
	This handy little function lets you interpret a 2d TGraph as a vector containing the same data.

Detailed Description

Function Documentation

TGraphToTH1D()

TH1D MaCh3Plotting::TGraphToTH1D	(	TGraph	graph,
		std::string	newName,
		std::string	newTitle
	)

This handy little function lets you interpret a TGraph as a TH1D.

It will go through your provided graph and make a histogram binning by taking the midpoints of all the graph points x values, then fill the histogram with the graphs y values. For the first and last points it will extend the binning out of the graph bounds using the width between the outermost and second outermost points. This can be useful if e.g. you want to draw cumulative stacks of LLH scans.

Parameters

graph	The graph you want to convert.
newName	The new name you want to give to the histogram. If not specified, will just use the name of the graph.
newTitle	The new title you want to give to the histogram. If not specified, will just use the title of the graph.

Definition at line 10 of file plottingUtils.cpp.

                                                                       {
  std::string name;
  std::string title;
 
  if (newName == "")
    name = graph.GetName();
  else
    name = newName;
 
  if (newTitle == "")
    title = graph.GetTitle();
  else
    title = newTitle;
 
  int nPoints = graph.GetN();
  if(nPoints < 2){
    MACH3LOG_ERROR("Too few points in the graph.");
    throw MaCh3Exception(__FILE__,__LINE__);
  }
  std::vector<double> pointsX(nPoints);
  std::vector<double> pointsY(nPoints);
 
  // Get the points out
  Double_t x, y;
 
  for (int pointId = 0; pointId < nPoints; pointId++)
  {
    graph.GetPoint(pointId, x, y);
    pointsX[pointId] = x;
    pointsY[pointId] = y;
  }
 
  // get the bin edges
  std::vector<double> binEdges(nPoints + 1);
  binEdges[0] = pointsX[0] - (pointsX[1] - pointsX[0]) / 2.0;
  binEdges[nPoints] = pointsX[nPoints - 1] + (pointsX[nPoints - 1] - pointsX[nPoints - 2]) / 2.0;
 
  for (int pointId = 1; pointId < nPoints; pointId++)
  {
    // take the midpoint of the two surrounding points
    binEdges[pointId] = (pointsX[pointId] + pointsX[pointId - 1]) / 2.0;
  }
 
  TH1D retHist = TH1D(name.c_str(), title.c_str(), nPoints, binEdges.data());
 
  for (int binId = 0; binId < nPoints; binId++)
  {
    retHist.SetBinContent(binId + 1, pointsY[binId]);
  }
 
  return retHist;
}

TGraphToVector() [1/2]

std::vector< std::vector< double > > MaCh3Plotting::TGraphToVector

(

TGraph

graph

)

This handy little function lets you interpret a TGraph as a vector containing the same data.

Parameters

graph

The graph you want to convert.

Returns

A vector of vectors containing the data from the initial graph. The first vector is the x axis, the 2nd the y axis

Definition at line 64 of file plottingUtils.cpp.

                                                          {
 
  int nPoints = graph.GetN();
  std::vector<std::vector<double>> ret(2);
  std::vector<double> pointsX(nPoints);
  std::vector<double> pointsY(nPoints);
 
  // Get the points out
  Double_t x, y;
 
  for (int pointId = 0; pointId < nPoints; pointId++)
  {
    graph.GetPoint(pointId, x, y);
    pointsX[pointId] = x;
    pointsY[pointId] = y;
  }
 
  ret[0] = pointsX;
  ret[1] = pointsY;
 
  return ret;
}

TGraphToVector() [2/2]

std::vector< std::vector< double > > MaCh3Plotting::TGraphToVector

(

TGraph2D

graph

)

This handy little function lets you interpret a 2d TGraph as a vector containing the same data.

Parameters

graph

The graph you want to convert.

Returns

A vector of vectors containing the data from the initial graph. The first vector is the x axis, the 2nd the y axis, the 3rd is the z axis

Definition at line 88 of file plottingUtils.cpp.

                                                            {
 
  int nPoints = graph.GetN();
  std::vector<std::vector<double>> ret(3);
  std::vector<double> pointsX(nPoints);
  std::vector<double> pointsY(nPoints);
  std::vector<double> pointsZ(nPoints);
 
  // Get the points out
  Double_t x, y, z;
 
  for (int pointId = 0; pointId < nPoints; pointId++)
  {
    graph.GetPoint(pointId, x, y, z);
    pointsX[pointId] = x;
    pointsY[pointId] = y;
    pointsZ[pointId] = z;
  }
 
  ret[0] = pointsX;
  ret[1] = pointsY;
  ret[2] = pointsZ;
 
  return ret;
}