Added python example script for beam divergence

Examples/python/simulation/ex010_BeamDivergence/BeamDivergence.py

+# Cylinder formfactor in DWBA with beam divergence
+import numpy
+import matplotlib
+import pylab
+from libBornAgainCore import *
+
+def get_sample():
+    """
+    Build and return the sample to calculate cylinder formfactor in Distorted Wave Born Approximation.
+    """
+    # defining materials
+    m_ambience = MaterialManager.getHomogeneousMaterial("Air", 0.0, 0.0)
+    m_substrate = MaterialManager.getHomogeneousMaterial("Substrate", 6e-6, 2e-8)
+    m_particle = MaterialManager.getHomogeneousMaterial("Particle", 6e-4, 2e-8)
+
+    # collection of particles
+    cylinder_ff = FormFactorCylinder(5*nanometer, 5*nanometer)
+    cylinder = Particle(m_particle, cylinder_ff)
+    particle_decoration = ParticleDecoration()
+    particle_decoration.addParticle(cylinder, 0.0, 1.0)
+    interference = InterferenceFunctionNone()
+    particle_decoration.addInterferenceFunction(interference)
+    air_layer = Layer(m_ambience)
+    air_layer.setDecoration(particle_decoration)
+    substrate_layer = Layer(m_substrate, 0)
+
+    multi_layer = MultiLayer()
+    multi_layer.addLayer(air_layer)
+    multi_layer.addLayer(substrate_layer)
+    return multi_layer
+
+def get_simulation():
+    """
+    Create and return GISAXS simulation with beam (+ divergence) and detector defined
+    """
+    simulation = Simulation()
+    simulation.setDetectorParameters(100, 0.0*degree, 2.0*degree, 100, 0.0*degree, 2.0*degree, True)
+    simulation.setBeamParameters(1.0*angstrom, 0.2*degree, 0.0*degree)
+    wavelength_distr = DistributionLogNormal(1.0*angstrom, 0.1)
+    alpha_distr = DistributionGaussian(-0.2*degree, 0.1*degree)
+    phi_distr = DistributionGaussian(0.0*degree, 0.1*degree)
+    simulation.addParameterDistribution("*/Beam/wavelength", wavelength_distr, 5)
+    simulation.addParameterDistribution("*/Beam/alpha", alpha_distr, 5)
+    simulation.addParameterDistribution("*/Beam/phi", phi_distr, 5)
+    return simulation
+
+
+def run_simulation():
+    """
+    Run simulation and plot results
+    """
+    sample = get_sample()
+    simulation = get_simulation()
+    simulation.setSample(sample)
+    simulation.printParameters()
+    simulation.runSimulation()
+    result = simulation.getIntensityData().getArray()
+    pylab.imshow(numpy.rot90(result + 1, 1), norm=matplotlib.colors.LogNorm(), extent=[0.0, 2.0, 0, 2.0])
+    pylab.colorbar()
+    pylab.show()
+
+if __name__ == '__main__':
+    run_simulation()
+
+