help-octave
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: differential and integral calculus


From: Paul Kienzle
Subject: Re: differential and integral calculus
Date: Fri, 4 Feb 2005 22:05:55 -0500

The symbolic toolbox in octave-forge can handle differentiation:

  octave:1> symbols
  octave:2> x=sym('x')
  x =

  x
  octave:3> f = x^3-2*x^2+5
  f =

  5.0+x^(3.0)-(2.0)*x^(2.0)
  octave:4> differentiate (f,x)
  ans =

  (3.0)*x^(2.0)-(4.0)*x

This can be improved somewhat with awkward syntax:

  octave:5> f = x^vpa("3")-vpa("2")*x^vpa("2")+vpa("5")
  f =

  5+x^3-2*x^2
  octave:6> differentiate (f,x)
  ans =

  3*x^2-4*x
  octave:7> f = Sin(x)*(x^vpa("3")-vpa("2")*x^vpa("2")+vpa("5"))
  f =

  (5+x^3-2*x^2)*sin(x)
  octave:8> differentiate (f,x)
  ans =

  (3*x^2-4*x)*sin(x)+cos(x)*(5+x^3-2*x^2)

To make it more usable, somebody could modify the type operations
to automatically recognize that they are working with integers and
create unlimited precision integers out of them.

There are also some primitive symbolic integration routines in the
underlying library GiNaC, but it only operates on polynomials.

- Paul

On Feb 3, 2005, at 2:32 PM, Andreas Volz wrote:

Hi,

I'm a octave newbie and try to work with differential and integral
calculus. I need some help to get a working example for this. Could you
help me?

Here is a simple example:

f(x)=x^3+-2x^2+5
f'(x)=3x^2-4x

and for example integrating f'(x) to see that f(x) results.

And what is with more difficult calculations? I know only the german
names, so perhaps I do a wrong translation. What is with chain rule
(Kettenregel), quotient rule (Quotientenregel) or all the other funny
things to do differential or integral calculus. Could octave detect
which rule to use for which function or have I to tell octave the right
rule? Can octave do a differential calculus for this?

f(x)=(x^2-3x)*sin x
f'(x)=?

I hope someone could help me with this questions. Some friends are
working with matlab or maple and told me this is working with this apps.
So I hope it works also with octave.

regards
Andreas



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------




-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------



reply via email to

[Prev in Thread] Current Thread [Next in Thread]