Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2001
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

[Date Index] [Thread Index] [Author Index]

Search the Archive

SetDelayed problems with matrix operation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg27341] SetDelayed problems with matrix operation
  • From: "SANCHEZ DE LEON, Guillermo" <gsl at fab.enusa.es>
  • Date: Wed, 21 Feb 2001 03:17:23 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Given a square matrix such as

A={{-3, 0, 0.05}, {0.8, -0.01, 0}, {0, 0.01, -0.05}}

I wish evalute the expresion:

{ x1[t_], x2[t_], x3[t_]} : = MatrixExp[A t].{b1, 0, 0}

I receive the message

SetDelayed::"shape": "Lists{ x1[t_], x2[t_], x3[t_] } and  MatrixExp[A t)] .
{b1, 0, 0} are not the same shape."

But it is known that when MatrixExp[A t].{b1, 0, 0} will be evaluate , given
a  value for t,  the solution  will be already a list of the same shape that
Lists{ x1[t_], x2[t_], x3[t_]} 

For instance: 

MatrixExp[A t].{b1, 0, 0}/.t->3 it work fine.

How it will be build the the expresion { x1[t_], x2[t_], x3[t_]} : =
MatrixExp[A t].{b1, 0, 0} to be evaluated?





  • Prev by Date: Re: simple Problem: D[ ]
  • Next by Date: Re: Graphing Functions
  • Previous by thread: Re: PALETTE
  • Next by thread: Re: SetDelayed problems with matrix operation