** Using gnuplot to perform "visual fit"**
# This script demonstrates user defined variables
# and user defined functions
a=7 # user defined
d=3 # user defined
f(x)=a*exp(-d*x*x) # user defined
set xrange [-2:2]
set yrange [0:a]
plot f(x)
having established this situation, you can now do the following:
gnuplot> a=5.5
gnuplot> replot
gnuplot> d=4
gnuplot> a=5.2
replot
And similar tests. If you also have some data, you can start by the
above definition, and then continue:
gnuplot> plot "data",f(x)
gnuplot> a=0.35
gnuplot> d=1.4
gnuplot> replot
until you have found a good combination of a,d which fits the data.

Task: consider this for the data in **b2s1s** etc. Which of the functions
can be approximated by gaussian (in fact, most have simple exponential tail
or 1/R, 1/R^2 behaviour....). Discuss this.
Index