Initial release of Maemo 5 port of gnuplot

[gnuplot] / demo / density.fnc

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+#
+#   This is a rough approach to fit a model function to the density
+#   data of a liquid crystal. The function consists of a linear
+#   branch for the high temperature region and of a curved branch with
+#   linear asymptote for the low temperatuer branch
+#
+
+#   free parameters:
+#   m1, m2  slopes of the linear function in the low and high T region
+#   Tc     transition temperature
+#   dens_Tc density at the transition temperature
+#   g      factor to scale tanh function
+
+ml     = -0.0001
+mh     = -0.0001
+dens_Tc = 1.020
+Tc     = 45
+g      = 1
+b      = 0.1
+
+
+high(x) = mh*(x-Tc) + dens_Tc
+lowlin(x)  = ml*(x-Tc) + dens_Tc
+curve(x) = b*tanh(g*(Tc-x))
+
+density(x) = x < Tc ? curve(x)+lowlin(x) : high(x)