Re: How to calculate gradient and laplace of a list

*To*: mathgroup at smc.vnet.net*Subject*: [mg72880] Re: How to calculate gradient and laplace of a list*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 24 Jan 2007 05:18:02 -0500 (EST)*Organization*: Uni Leipzig*References*: <ep4kd5$rat$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, you can only compute the derivative (or the second derivative, or the gradient) of a smooth function and not from discrete data. If you have a equdistant grid, you may use a discrete approximation of a derivative -- a finte difference expression, or you may construct an interpolation function ancd compute the derivative of the interpolated function. And vector field can be drawn with PlotField[] Regards Jens leoshen wrote: > Hi, guys > I have a matrix of n*m read from a file. mathematica has built in function > to do discrete fourier transform of the list. > Can I calculate the gradient and the laplace of the matrix? > I can use the listcontourplot to plot the matrix, Is there any way to plot > the gradient plot of it? > > > >