Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2010

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: discrete numerical 2D gradient

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114492] Re: discrete numerical 2D gradient
  • From: Sebastian Schmitt <sschmitt at physi.uni-heidelberg.de>
  • Date: Sun, 5 Dec 2010 21:55:46 -0500 (EST)

Hi!

Mark McClure wrote:
> On Tue, Oct 12, 2010 at 1:49 PM, Sebastian Schmitt
> <sschmitt at physi.uni-heidelberg.de> wrote:
> 
>> I have 2D data represented as a matrix. I would like to obtain the
>> gradient.
>> ...
>> Is there a better (both mathematical and Mathematical) to construct the
>> y-derivatives (dyMatrix)?
> 
> I would use ListInterpolation on your dataMatrix.  The result is an
> InterpolatingFunction that you can manipulate in all sorts of ways.
> 
> dataMatrix = Table[i*j, {i, 10}, {j, 10}];
> f = ListInterpolation[dataMatrix, {{0, 1}, {0, 1}}];
> grad[x_, y_] = {Derivative[1, 0][f][x, y],
>    Derivative[0, 1][f][x, y]};
> VectorPlot[grad[x, y], {x, 0, 1}, {y, 0, 1}]

grad[x_, y_] = D[f[x, y], {{x, y}}];

is possible as well.

Cheers,

Sebastian


  • Prev by Date: Re: How to bring up specific doc page programmatically?
  • Next by Date: DSolve on 'simple' differential equations
  • Previous by thread: Re: How to bring up specific doc page
  • Next by thread: DSolve on 'simple' differential equations