Re: Plotting numerical derivatives
- To: mathgroup at smc.vnet.net
- Subject: [mg53922] Re: Plotting numerical derivatives
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Fri, 4 Feb 2005 04:11:17 -0500 (EST)
- Organization: The University of Western Australia
- References: <ctnik9$f0e$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <ctnik9$f0e$1 at smc.vnet.net>, "plizak" <plizak at gmail.com> wrote: > I'm trying to differentiate a function of the form > > FTD[t1_, t2_] := a function of t1 and t2 > > I can get the derivative fine by using: > ND[ND[Fun[t1, t2 ], {t1, 1}, 200000], {t2, 1}, 200000 ] To require ND in NumericalMath`NLimit`, I assume that FTD must be a functino for which it is difficult or impossible to analytically compute the derivative? Is this the case? Otherwise you could just enter Derivative[1, 1][Fun][200000, 200000] > However, I'd like to plot it in a 3D plot, and it just doesn't want to > work. I get a flat plot with value 0. The code I tried to use is: > > Plot3D[ND[ND[Fun[t1, t2 ] , {t1, 1}, a] , {t2, 1}, b ], {a, 1, > 500000}, {b, 1, 500000}] > > Any tips on getting this to plot would be greatly appreciated! Plot3D has the HoldAll attribute so you would need to wrap an Evaluate[] around the first argument. Cheers, Paul -- Paul Abbott Phone: +61 8 6488 2734 School of Physics, M013 Fax: +61 8 6488 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul