Re: Function Fit to 3D data set
- To: mathgroup at smc.vnet.net
- Subject: [mg57796] Re: Function Fit to 3D data set
- From: dh <dh at metrohm.ch>
- Date: Wed, 8 Jun 2005 03:21:47 -0400 (EDT)
- References: <d83eh8$o6e$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
to plot points on an irregular 2 dim. grid, you can use:
DiscreteMath`ComputationalGeometry`TriangularSurfacePlot
sincerely, Daniel
Adrienne R wrote:
> I have been trying to do several analyses with an [x,y,z] data set, where z is dependent on x and y. First, I tried a 3D plot. However, the only way I was able to get Mathematica to plot my data was to assume a grid form for x and y, and use ListPlot3D. First question: can Mathematica make a 3D plot from stated x,y,z points?
>
> Secondly, I am trying to fit a function to the data. I have determined a function to which to fit parameters. However, Mathematica does not seem to want to accept y as a variable. Here is a simple suggestion of what I was trying. Note, my function is much more complicated. Please also ignore if the given does not work as stated, as I'm making it up.
>
> points = {{1, 1, 1}, {1, 2, 4}, {1, 4, 16}}
> f1 = FindFit[points, a + b*x^0 * y^1 + c*x^0 *y^2 +k*x^2 *y^0 + l*x^2 * y^1, {a, b, c, k, l}, x, y]
>
> The error I receive is \!\(\*
> RowBox[{\(FindFit::"nonopt
> "\), \(\(:\)\(\ \)\), "\<\"Options expected (
> instead of \\!\\(y\\)) beyond
> position \\!\\(4\\) in \\!\\(\[LeftSkeleton] 1 \[RightSkeleton]\\). An \
> option must be a rule or a list of rules. \\!\\(\\*ButtonBox[\\\"Moreâ?¦\\\", \
> ButtonStyle->\\\"RefGuideLinkText\\\", ButtonFrame->None, \
> ButtonData:>\\\"General::nonopt\\\"]\\)\"\>"}]\)
>
> Second question: Can Mathematica take a set of x,y,z data where z is dependent on x and y and fit a function to it?
>
> Secondary question for both: How?
>
> Thanks for the help!
>