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MathGroup Archive 2008

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Problem using Solve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg89728] Problem using Solve
  • From: "Dario Caldara" <dario.caldara at gmail.com>
  • Date: Thu, 19 Jun 2008 05:42:39 -0400 (EDT)

Dear Sirs,

I am new to Mathematica. I am trying to solve a linear system of equations
(28 equations/unknowns). The coefficients of this system of equations are
function of a set of parameters (deep parameters of my model). I need to
solve this system of equations for different values of the deep parameters.
To solve the system I use the following command:

solution = Solve[Thread[test4[[cho2]] == 0]];

I can solve the system of equations for some values of the parameters. But
in most cases I get the following warning message:

RowReduce::luc: "Result for RowReduce of badly conditioned matrix \
{{0.0920865234989278,0.*10^-16,0,0,0,0,0,0,0,0,<<19>>},<<9>>,<<18>>} \
may contain significant numerical errors"

I do not know how to interpret and make good use of the information
contained in this message. To what extend can I trust the output of
Mathematica? Is there anything I can do to fix this problem? The parameter
values I use are in a range for which - according to theory - a solution to
the system exists.

I apologize if my question is trivial or if I was not clear enough. I am
ready to provide any further explanation

Kind Regards

Dario



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