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gnu tool


Create plots via GnuPlot plotting program.


The gnu tool is a wrapper on the GnuPlot plotting package. GnuPlot is open source software and runs on any platform.

The gnu constructor launches GnuPlot as a process which the gnu tool sends commands to. The GnuPlot process can be killed via the stop() method, though this is typically unnecessary.

The plot() method plots a single vector against a linear index or pairs of vectors against each other. The pairs of vectors are written to files and read-in by GnuPlot's plot command.

The mplot() method creates a series of plots and saves them each to a numbered file. Each file is a plot of an increasing portion of the vector(s). This can be used to make an animation of a plot.

The enter() method can be used to interact with GnuPlot directly. Each subsequent line you type is a GnuPlot command, until you type "quit" or "exit" to return to Single GnuPlot commands can be issued as string arguments to the gnu tool.

The export() method writes numeric data as columns to text files, so that GnuPlot can read them via its "plot" command.

Mutliple windows can be displayed, plotted to, and manipulated using the select() and hide() methods. The save() method writes the currently selected plot to a PostScript file.

The remaining methods (aspect, title, xrange, etc) set attributes of the currently selected plot. The erase() method resets all attributes to their default values.


g = gnu()		       start up GnuPlot
g.stop()		       shut down GnuPlot process 
g.plot(a)                      plot vector A against linear index
g.plot(a,b)	 	       plot B against A
g.plot(a,b,c,d,...)	       plot B against A, D against C, etc
g.mplot(M,N,S,"file",a,b,...)  multiple plots saved to file0000.eps, etc 
  each plot argument can be a tuple, list, or Numeric/NumPy vector
  mplot loops over range(M,N,S) and create one plot per iteration
    last args are same as list of vectors for plot(), e.g. 1, 2, 4 vectors
    each plot is made from a portion of the vectors, depending on loop index i
      Ith plot is of b[0:i] vs a[0:i], etc
    series of plots saved as file0000.eps, file0001.eps, etc
    if use xrange(),yrange() then plot axes will be same for all plots 
g("plot 'file.dat' using 2:3 with lines")      execute string in GnuPlot 
g.enter()	   	                enter GnuPlot shell
gnuplot> plot sin(x) with lines         type commands directly to GnuPlot
gnuplot> exit, quit	      	        exit GnuPlot shell 
g.export("data",range(100),a,...)       create file with columns of numbers 
  all vectors must be of equal length
  could plot from file with GnuPlot command: plot 'data' using 1:2 with lines  	               figure N becomes the current plot 
  subsequent commands apply to this plot 
g.hide(N)  	               delete window for figure N"file")	               save current plot as file.eps 
Set attributes for current plot: 
g.erase()                      reset all attributes to default values
g.aspect(1.3)                  aspect ratio
g.xtitle("Time")               x axis text
g.ytitle("Energy")             y axis text
g.title("My Plot")             title text
g.title("title","x","y")       title, x axis, y axis text
g.xrange(xmin,xmax)            x axis range
g.xrange()                     default x axis range
g.yrange(ymin,ymax)            y axis range
g.yrange()                     default y axis range
g.xlog()                       toggle x axis between linear and log
g.ylog()                       toggle y axis between linear and log
g.label(x,y,"text")            place label at x,y coords
g.curve(N,'r')                 set color of curve N 
  colors: 'k' = black, 'r' = red, 'g' = green, 'b' = blue
          'm' = magenta, 'c' = cyan, 'y' = yellow 

Related tools:

matlab, plotview


GnuPlot plotting package.