2.9 Differences Between PyXPlot and Gnuplot

The commands supported by PyXPlot are only a subset of those available in gnuplot, although most of its functionality is present. Features which are supported by this version include:

• Allocation of user-defined variables and functions.
• The print, help, exit and quit commands.
• The reset and clear commands.
• The ! command, to execute the remainder of the line as a shell command, e.g. !ls.
• The cd and pwd commands, to change and display the current working directory.
• The use of ` ` back-quotes to substitute the output of a shell command.^2.7
• Set plot titles, axis labels, axis ranges, pointsize, linestyles, etc.
• Fitting of functions to data via the fit command.
• Basic 2d plotting and replotting of functions and datafiles, with the following styles: lines, points, linespoints, dots, boxes, steps, fsteps, histeps, impulses, csplines, acsplines and errorbars of all flavours (see section 3.3 for details of changes to errorbars).
• Automatic and manual selection of linestyles, linetypes, linewidths, pointtypes and pointsizes.
• Use of dual axes. Note: Operation here differs slightly from original gnuplot; dual axes are displayed whenever they are defined, there is no need to set xtics nomirror. See the details in the following section.
• Placing arrows and textual labels on plots.
• Putting grids on plots (colour can be set, but not linestyle).
• Setting plot aspect ratios with set size ratio or set size square.
• Multiplot (which is very significantly improved over gnuplot; see section 3.5)

Gnuplot features which PyXPlot does not presently support include:

• Parametric function plotting.
• Three-dimensional plotting (i.e. the splot command).
• Setting major/minor tics (but PyXPlot always gets this right without being told anyway ).^2.8