Re: Function of N variable
- To: mathgroup at smc.vnet.net
- Subject: [mg121101] Re: Function of N variable
- From: Sam Takoy <sam.takoy at yahoo.com>
- Date: Sun, 28 Aug 2011 04:05:18 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201108271217.IAA17765@smc.vnet.net> <857CDCC2-6748-4EAD-B709-5092D1E6CBB6@gmail.com>
- Reply-to: Sam Takoy <sam.takoy at yahoo.com>
E.G, the following? Grad[f_][x__] := Switch[Length[{x}], 1, {Derivative[1][f][x]}, 2, {Derivative[1, 0][f][x], Derivative[0, 1][f][x]}, 3, {Derivative[1, 0, 0][f][x], Derivative[0, 1, 0][f][x], Derivative[0, 0, 1][f][x]}, 4, {Derivative[1, 0, 0, 0][f][x], Derivative[0, 1, 0, 0][f][x], Derivative[0, 0, 1, 0][f][x], Derivative[0, 0, 0, 1][f][x]}] f[x_, y_] = x^2 + y^2; Grad[f][x, y] Thanks! ________________________________ From: Ethan Dyer <ethansdyer at gmail.com> To: Sam Takoy <sam.takoy at yahoo.com> Cc: "mathgroup at smc.vnet.net" <mathgroup at smc.vnet.net> Sent: Saturday, August 27, 2011 9:24 AM Subject: [mg121101] Re: Function of N variable Sam, Mathematica allows one to define functions that take an arbitrary number of arguments using double underscore (BlankSequence) or triple underscore (BlankNullSequence) For instance F[args__]:={args} takes in any number of arguments except zero. A function defined with three underscores can take any number including zero. Ethan On Aug 27, 2011, at 8:17 AM, Sam Takoy <sam.takoy at yahoo.com> wrote: > Hi, > > I have put together a few function for differential geometry in 3D. > All my functions were of the kind F(z1_, z2_, z3_). Now I want to > generalize to 4D, then 5D, etc. Is there a good way to represent a > function of N variables? For example, I want to be able to say grad[F] > [???] to obtain a list of N function (partial derivatives) of N > variables. I understand these are vague questions, but I am only > looking for some keywords. > > Many thanks in advance, > > > Sam >
- References:
- Function of N variable
- From: Sam Takoy <sam.takoy@yahoo.com>
- Function of N variable