
Re: Newton Raphson for nxn system using symbolic toolbox
Posted:
Nov 11, 2011 10:17 AM


Christopher Creutzig <Christopher.Creutzig@mathworks.com> wrote in message <4EBA8B5A.5090609@mathworks.com>... > On 01.11.11 11:20, Uwe Brauer wrote: > > > Here is an example trying to use vectors > > clear all > > syms x y > > e=[x y] > > f1=sin(e(1)e(2)) > > e(1)=1 > > e(2)=1 > > eval(f1) > > Instead of assigning, try > > subs(f1, e, [1 1]) > > Or, as Alan pointed out, convert f1 to a MATLAB function. If you have > multiple evaluations of the same symbolic expression, that will usually > be faster. > > > Christopher
unfortunately my Matlab version does not provide this feature for symbolic expressions
But my main problem remains.
I can perfectly write matlab code for solving Newton Raphson for any nxn system, since Matlab uses dynamic memory, and I have to use as a entry variable the system I want to solve and its jacobian.
However when i only want to have the system and use Matlabs symbolic tool to calculate the jacobian I do not know how to do that since I don't know the size of the jacobian in advance.
Uwe

