DSolve for a system of 3 equations
- To: mathgroup at smc.vnet.net
- Subject: [mg36274] DSolve for a system of 3 equations
- From: Neil Klepeis <nklepeis at uclink4.berkeley.edu>
- Date: Thu, 29 Aug 2002 01:38:00 -0400 (EDT)
- Organization: Lawrence Berkeley National Laboratory
- Reply-to: nklepeis at uclink4.berkeley.edu
- Sender: owner-wri-mathgroup at wolfram.com
I try to solve a three equation linear ODE system with constant
coefficients and Mathematica 3.0 (Intel/Linux) chokes (see below).
When I try the same thing on Mathematica 4.0 (Solaris) I get a very
strange result containing things like "E^x#1" OR "#1^2".
Am I doing something wrong, or is there a bug/problem with Mathematica.
Regards,
Neil
-- Solving a Three Equation ODE system (Linear with Constant
Coefficients) with Mathematica 3.0 ----
INPUT:
DSolve[{y1'[x] + c11*y1[x] + c12*y2[x] +c13*y3[x] +c1==0,
y2'[x]+c21*y1[x]+c22*y2[x]+c23*y3[x]+c2==0,
y3'[x]+c31*y1[x]+c32*y2[x]+c33*y3[x]+c3==0,
y1[0]==y1i, y2[0]==y2i, y3[0]==y3i},
{y1[x], y2[x], y3[x]}, x]
OUTPUT:
Eigensystem::"eivec":
"Unable to find eigenvector for eigenvalue \!\(Root[\(\(\(\(c13\\
c22\\ \
c31\) - \(c12\\ c23\\ c31\) - \(c13\\ c21\\ c32\) + \(c11\\ c23\\ c32\) + \
\(\\[LeftSkeleton] 20 \\[RightSkeleton]\)\) &\), 1\)]\)."
Eigensystem::"eivec":
"Unable to find eigenvector for eigenvalue \!\(Root[\(\(\(\(c13\\
c22\\ \
c31\) - \(c12\\ c23\\ c31\) - \(c13\\ c21\\ c32\) + \(c11\\ c23\\ c32\) + \
\(\\[LeftSkeleton] 20 \\[RightSkeleton]\)\) &\), 2\)]\)."
Eigensystem::"eivec":
"Unable to find eigenvector for eigenvalue \!\(Root[\(\(\(\(c13\\
c22\\ \
c31\) - \(c12\\ c23\\ c31\) - \(c13\\ c21\\ c32\) + \(c11\\ c23\\ c32\) + \
\(\\[LeftSkeleton] 20 \\[RightSkeleton]\)\) &\), 3\)]\)."
General::"stop":
"Further output of \!\(Eigensystem :: \"eivec\"\) will be suppressed \
during this calculation."
--
______________________________________________________
Neil E. Klepeis, UC Berkeley, School of Public Health,
and Lawrence Berkeley National Laboratory,