Initial release of Maemo 5 port of gnuplot

[gnuplot] / demo / reflect.fnc

diff --git a/demo/reflect.fnc b/demo/reflect.fnc
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+#
+#   Model function for Reflectivity evaluation
+#
+
+mu = 1.130469005513490E-001                     # (cm-1) @ 17.479 keV
+t0 = 0.18                                       # cm
+tb = 11.417823202820120 * 0.01745329251994      # thetaB (radians)
+A = mu * t0 / cos(tb)
+P = (1 + (cos(2.*tb))**2) / 2
+Fhkl = sqrt(3.536346308456155**2 + (4.58815426260982e-4)**2) * 0.968
+r0 = 2.81794092e-13                             # classical electron radius
+lambda = 7.09338062818239e-9                    # Mo K in cm
+V = 1.62253546981499e-23
+P = (1. + (cos(2.*tb))**2) / 2.
+#
+# combine constants to avoid exponential overflow on systems with
+# D floating point format where exponential limits are ca. 10**(+/-38)
+# r0liV = r0 * lambda / V
+r0liV = 2.81794092*7.09338062818239/1.62253546981499e-1
+#
+
+W(x) = 1./(sqrt(2.*pi)*eta) * exp( -1. * x**2 / (2.*eta**2) )
+Y(tc) = tc/sin(tb) * Fhkl * r0liV
+f(tc)= (tanh(Y(tc)) + abs(cos(2.*tb)) * tanh(abs(Y(tc)*cos(2.*tb)))) / (Y(tc)*(1.+(cos(2.*tb))**2))
+Q(tc) = (r0*Fhkl/V)**2 * (lambda**3/sin(2.*tb)) * P * f(tc)
+a(x) = W(x) * Q(tc) / mu
+
+#
+
+R(x) = sinh(A*a(x)) * exp(-1.*A*(1.+a(x)))