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{ SUM.PDE  

 

 This example demonstrates the use of the SUM function.

 It poses a heatflow problem with a heat source made up of four

 gaussians.  The source is composed by a SUM over gaussians

 referenced to arrays of center coordinates.

 

}

title 'Sum test'

Variables

   u

definitions

   k = 1

   u0 = 1-x^2-y^2     { boundary forced to parabolic values }

   xc = array(-0.5,0.5,0.5,-0.5) { arrays of source spot coordinates }

   yc = array(-0.5,-0.5,0.5,0.5)

   s = sum( i, 1, 4, exp(-10*((x-xc[i])^2+(y-yc[i])^2)) )       { summed Gaussian source }