Plotting Poins From Array

[Anonymous]

I have a 3 arrays, one containing x values, one containing y values, one
containing z values.

I would like to know how i can use MathGL to make a 3d scatter plot of this
points.

Any help would be appreciated.

This was my attempt, but there is nothing displayed:

#include <QApplication>
#include <QDialog>
#include <QLabel>
#include <QPixmap>
#include <QVBoxLayout>
#include <iostream>
#include <fstream>
#include <vector>
#include <mgl/mgl.h>
#include <mgl/mgl_qt.h>

using namespace std;
int main(int argc, char* argv[])
{
  //Qt startup
  QApplication a(argc, argv);

  mglData dataX(40200);
  mglData dataY(40200);
  mglData dataZ(40200);
  //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    vector<double> x;
    vector<double> y;
    vector<double> rx;
    vector<double> lx;
    vector<double> ry;
    vector<double> ly;
    vector<double> rz;
    vector<double> lz;

    int i = 0;
    int flag = 0;
    double thisSalary;
    ifstream empFile;
    empFile.open("E_field.gnu");

    while(empFile>>thisSalary)
            {
                    /*empFile >> thisSalary;
                    cout<<thisSalary<<endl;
                    i++;*/
                    //cout<<flag<<endl;
                    if(flag == 0 && !empFile.eof())
                    {
                            //empFile >> thisSalary;
                            x.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 1)
                    {
                            //empFile >> thisSalary;
                            y.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 2)
                    {
                            //empFile >> thisSalary;
                            rx.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 3)
                    {
                            //empFile >> thisSalary;
                            lx.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 4)
                    {
                            //empFile >> thisSalary;
                            ry.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 5)
                    {
                            //empFile >> thisSalary;
                            ly.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 6)
                    {
                            //empFile >> thisSalary;
                            rz.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 7)
                    {
                            //empFile >> thisSalary;
                            lz.push_back(thisSalary);
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 8)
                    {
                            //empFile >> thisSalary;
                            //cout<<thisSalary<<endl;
                            flag++;
                            i++;
                    }
                    else if(flag == 9)
                    {
                            //empFile >> thisSalary;
                            //cout<<thisSalary<<endl;
                            flag = 0;
                            i++;
                    }

            }
            empFile.close();

  //Populate array

  for(int i =0; i<40200; i++)
  {
    dataX.a[i] = x[i];
    dataY.a[i] = y[i];
    dataZ.a[i] = ry[i];
  }

  //Using MathGL to write a plot to file
  cout<<x.size()<<endl;
  mglGraphZB plot;
  plot.Alpha(true);
  plot.Light(true);
  plot.Light(0,mglPoint(1,0,-1));
  mglData data(2,2);
  data.Modify("x*y");
  plot.Axis(mglPoint(0,0,0),mglPoint(1,1,1));
  plot.Rotate(80,40);
  plot.Plot(dataZ);
  plot.Box();
  plot.Puts(mglPoint(0.7,1,1.2),"a(x,y)");
  plot.WriteBMP("CppMathGlExample1.bmp");

  //Use Qt to display the saved plot
  QDialog dialog;
  QVBoxLayout layout;
  QPixmap pixmap("CppMathGlExample1.bmp");
  QLabel label;
  label.setPixmap(pixmap);
  layout.addWidget(&label);
  dialog.setLayout(&layout);
  dialog.show();
  return a.exec();
}

[Alexey Balakin]

Just use parametric form of Plot() function. But first you need to be ensure
that yours data are located inside the axis range. The code can look like

plot.SetRanges(dataX,dataY,dataZ);  // to be sure that data points are visible
plot.Plot(dataX,dataY,dataZ);