Re: Need help w- simple program

*To*: mathgroup at smc.vnet.net*Subject*: [mg115182] Re: Need help w- simple program*From*: Vincent <sheeplane at gmail.com>*Date*: Tue, 4 Jan 2011 04:21:25 -0500 (EST)*References*: <ifpj03$b2r$1@smc.vnet.net>

On 2 Jan., 11:11, "xscr... at gmail.com" <xscr... at gmail.com> wrote: > i purchased a copy of home edition. As my first programming project, > I'd like to simulate a lambertian (e.g. Intensity is a function of cos > theta) led light source and plot the light intensity impinging on a > surface 12" away. I'd like to plot the surface as 1024x1024 points > with different colors for ranges of intensities. > > I know this is pretty simple with Mathematica, unfortunately I have no > experience with Mathematica and don't know where to begin. > > Help! > > Thanks, > > Per You could rewrite the intensity to be a function of the xy coordinates of the plane, then use contourplot to generate a plot of it. If you really need the number of points to be 1024x1024, then use table to generate a matrix of the colorintensites and use arrayplot to generate an image. Here is an example with the intensity function given just substituted by f which is just the radius. f[x_, y_] := Sqrt[x^2 + y^2] ContourPlot[f[x,y], {x, -5, 5}, {y, -5, 5},PlotRange -> Full] ArrayPlot[Table[f[x,y], {x, -5., 5., 10./(1024 - 1)}, {y, -5., 5., 10./ (1024 - 1)}], PlotRange -> Full] I'll leave finding the correct form of f[x,y] up to you, but it's a simple trigonometric assignment.