plot

subroutine plot(xin, yin, color, linewidth, marker, markersize, noline, legend)

Description:

Our toolbox provides a set of routines that can be used for plotting graphs directly out of your Fortran program. The plotting process for 2D-graphs thereby consists of two steps. The subroutines plot and plot_hist allow to add plotdata (i.e. lines, dots and histograms) to your plots (almost as many as you want). After you’ve added all the necessary data to your plot, you can start the plotting process by means of the subroutine execplot, which will transfer your plot data to the program GNUplot and start this program, so that your graphs will be displayed in a pop-up window.

The subroutine plot add as line made of the x-y-data-pairs xi and yi to your plot. It also contains a couple of optional plot formatting inputs.

Input arguments:

• real*8 :: xin(:)
  This is a one-dimensional array of arbitrary length that contains the x-data for plotting.
• real*8 :: yin(:)
  This is a one-dimensional array that contains the y-data for plotting. This array needs to have exactly the same length as the array xin. Otherwise the subroutine throws an error message.

Optional arguments:

• character(LEN=*) :: color
  This character argument allows to specify the color of the line that should be drawn. You can use both literal color names like 'blue' or 'red' or hexadecimal color codes like '#0000FF' for blue or '#FF0000' for red. The internet offers multiple sources that allow you to determine the hexadecimal codes of colors. For further information about colors in GNUplot, you can look at its documentation. If no color value is specified, then the plotting routine will give each line a different color according to a predetermined color scheme.
• real*8 :: linewidth
  This variable specifies the width of the line that should be drawn. The default linewidth is equal to 2d0.
• integer :: marker
  This variable specifies whether a marker should be placed on each x-y-data-pair and how this marker should look like. If this argument is not present when the subroutine plot is called, then no marker will be placed. If this argument is present in your subroutine call, then you can choose among 13 different markers. Just try out for yourself how they look like. Note that when the nolines option is set to .true., then markers are placed automatically on this plot.
• real*8 :: markersize
  This variable specifies the size of the markers set on each x-y-data-pair. The default markersize is equal to 1d0.
• logical :: noline
  If this logical variable is present and set to a value of .true., then there will be no connecting line between the x-y-data-pairs supplied in xi and yi. Instead, the subroutine will only draw markers for each x-y-data-pair.
• character(LEN=*) :: legend
  Through this character variable of arbitrary length, you can supply a legend entry for the respective line you want to plot.

References

• For further reading refer to:
  • The gnuplot documentation.
• This routine is used in the following programs:
  • prog01_17.f90
  • prog02_15.f90
  • prog02_16.f90
  • prog02_17.f90
  • prog02_18.f90
  • prog04_01.f90
  • prog04_04.f90
  • prog04_05.f90
  • prog04_08.f90
  • prog04_09.f90
  • prog08_01.f90
  • prog08_02.f90
  • prog08_03.f90
  • prog08_04.f90
  • prog08_05.f90
  • prog08_06.f90
  • prog08_07.f90
  • prog09_01.f90
  • prog09_02.f90
  • prog09_03.f90
  • prog09_04.f90
  • prog09_09.f90
  • prog09_10.f90
  • prog10_01.f90
  • prog10_02.f90
  • prog10_03.f90
  • prog10_04.f90
  • prog10_05.f90
  • prog10_06.f90