295 lines
8.1 KiB
ReStructuredText
295 lines
8.1 KiB
ReStructuredText
.. include:: replace.txt
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Making Plots using the Gnuplot Class
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------------------------------------
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There are 2 common methods to make a plot using |ns3| and gnuplot (http://www.gnuplot.info):
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#. Create a gnuplot control file using |ns3|'s Gnuplot class.
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#. Create a gnuplot data file using values generated by |ns3|.
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This section is about method 1, i.e. it is about how to make a plot using |ns3|'s Gnuplot class. If you are interested in method 2, see the "A Real Example" subsection under the "Tracing" section in the |ns3| `Tutorial <http://www.nsnam.org/tutorials.html>`_.
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Creating Plots Using the Gnuplot Class
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**************************************
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The following steps must be taken in order to create a plot using |ns3|'s Gnuplot class:
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#. Modify your code so that is uses the Gnuplot class and its functions.
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#. Run your code so that it creates a gnuplot control file.
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#. Call gnuplot with the name of the gnuplot control file.
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#. View the graphics file that was produced in your favorite graphics viewer.
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See the code from the example plots that are discussed below for details on step 1.
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An Example Program that Uses the Gnuplot Class
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**********************************************
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An example program that uses |ns3|'s Gnuplot class can be found here: ::
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src/tools/examples/gnuplot-example.cc
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In order to run this example, do the following: ::
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./waf shell
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cd build/debug/src/tools/examples
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./gnuplot-example
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This should produce the following gnuplot control files in the directory where the example is located: ::
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plot-2d.plt
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plot-2d-with-error-bars.plt
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plot-3d.plt
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In order to process these gnuplot control files, do the following: ::
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gnuplot plot-2d.plt
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gnuplot plot-2d-with-error-bars.plt
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gnuplot plot-3d.plt
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This should produce the following graphics files in the directory where the example is located: ::
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plot-2d.png
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plot-2d-with-error-bars.png
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plot-3d.png
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You can view these graphics files in your favorite graphics viewer. If you have gimp installed on your machine, for example, you can do this: ::
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gimp plot-2d.png
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gimp plot-2d-with-error-bars.png
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gimp plot-3d.png
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An Example 2-Dimensional Plot
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*****************************
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The following 2-Dimensional plot
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.. _plot-2d:
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.. figure:: figures/plot-2d.*
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was created using the following code from gnuplot-example.cc: ::
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using namespace std;
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string fileNameWithNoExtension = "plot-2d";
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string graphicsFileName = fileNameWithNoExtension + ".png";
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string plotFileName = fileNameWithNoExtension + ".plt";
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string plotTitle = "2-D Plot";
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string dataTitle = "2-D Data";
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// Instantiate the plot and set its title.
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Gnuplot plot (graphicsFileName);
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plot.SetTitle (plotTitle);
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// Make the graphics file, which the plot file will create when it
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// is used with Gnuplot, be a PNG file.
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plot.SetTerminal ("png");
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// Set the labels for each axis.
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plot.SetLegend ("X Values", "Y Values");
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// Set the range for the x axis.
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plot.AppendExtra ("set xrange [-6:+6]");
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// Instantiate the dataset, set its title, and make the points be
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// plotted along with connecting lines.
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Gnuplot2dDataset dataset;
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dataset.SetTitle (dataTitle);
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dataset.SetStyle (Gnuplot2dDataset::LINES_POINTS);
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double x;
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double y;
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// Create the 2-D dataset.
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for (x = -5.0; x <= +5.0; x += 1.0)
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{
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// Calculate the 2-D curve
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//
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// 2
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// y = x .
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//
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y = x * x;
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// Add this point.
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dataset.Add (x, y);
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}
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// Add the dataset to the plot.
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plot.AddDataset (dataset);
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// Open the plot file.
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ofstream plotFile (plotFileName.c_str());
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// Write the plot file.
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plot.GenerateOutput (plotFile);
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// Close the plot file.
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plotFile.close ();
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An Example 2-Dimensional Plot with Error Bars
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*********************************************
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The following 2-Dimensional plot with error bars in the x and y directions
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.. _plot-2d-with-error-bars:
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.. figure:: figures/plot-2d-with-error-bars.*
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was created using the following code from gnuplot-example.cc: ::
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using namespace std;
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string fileNameWithNoExtension = "plot-2d-with-error-bars";
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string graphicsFileName = fileNameWithNoExtension + ".png";
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string plotFileName = fileNameWithNoExtension + ".plt";
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string plotTitle = "2-D Plot With Error Bars";
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string dataTitle = "2-D Data With Error Bars";
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// Instantiate the plot and set its title.
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Gnuplot plot (graphicsFileName);
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plot.SetTitle (plotTitle);
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// Make the graphics file, which the plot file will create when it
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// is used with Gnuplot, be a PNG file.
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plot.SetTerminal ("png");
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// Set the labels for each axis.
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plot.SetLegend ("X Values", "Y Values");
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// Set the range for the x axis.
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plot.AppendExtra ("set xrange [-6:+6]");
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// Instantiate the dataset, set its title, and make the points be
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// plotted with no connecting lines.
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Gnuplot2dDataset dataset;
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dataset.SetTitle (dataTitle);
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dataset.SetStyle (Gnuplot2dDataset::POINTS);
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// Make the dataset have error bars in both the x and y directions.
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dataset.SetErrorBars (Gnuplot2dDataset::XY);
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double x;
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double xErrorDelta;
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double y;
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double yErrorDelta;
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// Create the 2-D dataset.
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for (x = -5.0; x <= +5.0; x += 1.0)
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{
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// Calculate the 2-D curve
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//
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// 2
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// y = x .
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//
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y = x * x;
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// Make the uncertainty in the x direction be constant and make
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// the uncertainty in the y direction be a constant fraction of
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// y's value.
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xErrorDelta = 0.25;
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yErrorDelta = 0.1 * y;
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// Add this point with uncertainties in both the x and y
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// direction.
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dataset.Add (x, y, xErrorDelta, yErrorDelta);
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}
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// Add the dataset to the plot.
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plot.AddDataset (dataset);
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// Open the plot file.
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ofstream plotFile (plotFileName.c_str());
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// Write the plot file.
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plot.GenerateOutput (plotFile);
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// Close the plot file.
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plotFile.close ();
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An Example 3-Dimensional Plot
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*****************************
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The following 3-Dimensional plot
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.. _plot-3d:
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.. figure:: figures/plot-3d.*
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was created using the following code from gnuplot-example.cc: ::
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using namespace std;
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string fileNameWithNoExtension = "plot-3d";
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string graphicsFileName = fileNameWithNoExtension + ".png";
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string plotFileName = fileNameWithNoExtension + ".plt";
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string plotTitle = "3-D Plot";
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string dataTitle = "3-D Data";
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// Instantiate the plot and set its title.
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Gnuplot plot (graphicsFileName);
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plot.SetTitle (plotTitle);
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// Make the graphics file, which the plot file will create when it
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// is used with Gnuplot, be a PNG file.
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plot.SetTerminal ("png");
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// Rotate the plot 30 degrees around the x axis and then rotate the
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// plot 120 degrees around the new z axis.
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plot.AppendExtra ("set view 30, 120, 1.0, 1.0");
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// Make the zero for the z-axis be in the x-axis and y-axis plane.
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plot.AppendExtra ("set ticslevel 0");
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// Set the labels for each axis.
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plot.AppendExtra ("set xlabel 'X Values'");
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plot.AppendExtra ("set ylabel 'Y Values'");
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plot.AppendExtra ("set zlabel 'Z Values'");
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// Set the ranges for the x and y axis.
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plot.AppendExtra ("set xrange [-5:+5]");
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plot.AppendExtra ("set yrange [-5:+5]");
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// Instantiate the dataset, set its title, and make the points be
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// connected by lines.
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Gnuplot3dDataset dataset;
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dataset.SetTitle (dataTitle);
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dataset.SetStyle ("with lines");
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double x;
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double y;
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double z;
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// Create the 3-D dataset.
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for (x = -5.0; x <= +5.0; x += 1.0)
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{
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for (y = -5.0; y <= +5.0; y += 1.0)
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{
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// Calculate the 3-D surface
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//
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// 2 2
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// z = x * y .
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//
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z = x * x * y * y;
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// Add this point.
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dataset.Add (x, y, z);
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}
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// The blank line is necessary at the end of each x value's data
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// points for the 3-D surface grid to work.
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dataset.AddEmptyLine ();
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}
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// Add the dataset to the plot.
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plot.AddDataset (dataset);
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// Open the plot file.
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ofstream plotFile (plotFileName.c_str());
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// Write the plot file.
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plot.GenerateOutput (plotFile);
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// Close the plot file.
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plotFile.close ();
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