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?
>
>
>
>