Download User Guide Version 6.0 - RWTH Aachen University

Chapter 6 gnuplot
6.2. Plotting data and fitting curves
The possibilities of plotting MICRESS® data and fitting curves will be explained with the help
of the “Grain Growth” example. This example is stored in the MICRESS® installation directory.
Let's consider that you would like to plot the average grain radius over time. This information
can be found in the Grain_Growth_.TabK -file (see Figure 6.3.) in the “Grain Growth” result
directory. The details for this procedure are explained in fig. 6.2:
Fig 6.2 Command-line input for plotting data and
fitting curves
First specify the path of the respective result file.
Then label the axes of the desired plot. If you do
not wish to have a legend, use the command “set
nokey”. Since this is a 2D plot, only labels for the
X and the Y axis are necessary. This is done with
the commands set xlabel and set ylabel, resp.
The time t for microstructure evolution will be
plotted along the X-axis and the grain radius in
micrometers will be plotted along the Y-axis. The
columns of the data to be plotted are specified by
typing e.g. “plot "Grain_Growth_TabK.txt" u 1:2 w
l lw 2” where “u 1:2” indicates, that column 2 of
the table (see fig 6.2) shall be plotted over
column 1 by using a line (w l “with line”) and the
line width (lw) shall be 2.
MICRESS® User Guide Volume III: Post-Processing
gnuplot Command-Line
gnuplot> cd 'C:\Desktop\Results_Grain_Growth
gnuplot> set nokey
gnuplot> set xlabel "t"
gnuplot> set ylabel "R/µm"
gnuplot> plot "Grain_Growth_TabK.txt" u 1:2 w l lw 2
….
gnuplot> f(x) = R0 + k*x**m
gnuplot> R0=1
gnuplot> k=1
gnuplot> m=1
gnuplot> fit f(x) "Grain_Growth_TabK.txt" u 1:2 via
R0,k,m
gnuplot> replot f(x) w lines
gnuplot> print "R0:", R0, "µm"
gnuplot> print "k:", k
gnuplot> print "m:", m
gnuplot> pause -1
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