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## Re: Differenciate

 From: Etienne Grossmann Subject: Re: Differenciate Date: Wed, 11 Jul 2001 16:51:24 +0100 User-agent: WEMI/1.13.7 (Shimada) FLIM/1.13.2 (Kasanui) Emacs/20.7 (i386-debian-linux-gnu) (with unibyte mode)

```  Hello,

#  Hello everybody,
#
#  Can someone tell me how to do a numerical derivative of a function with
#  octave? Must I implement the algoritm?
#
#  Thanks,
#          Santiago

You can do symmetric differiation w/ the function 'cdiff' below. For
example, if 'f' takes an argument 'v'of size 2x3, and returns a 4x5
matrix 'u'

c = cdiff ('f');      # Code for the numerical differential 'df'
eval (c);             # Define 'df'
du = df (v)           # Differential of f at v. Size is (2*6)x(4*5)

d u(i)
Here, du(i,j) is an approximation of  ------
d v(j)

Hth,

Etienne

ps : You can differentiate functions w/ more than one argument wrt any
one of the arguments; you can choose the discretization step
etc. See below.

```

cdiff.m
Description: Binary data