RE: [R] Roots of quadratic system.

From: <Bill.Venables_at_csiro.au>
Date: Mon 02 May 2005 - 10:20:11 EST


Are you looking for a unique solution or families of solutions?

Can't you turn a root-finding problem for a system of equations with a unique solution into an optimisation problem, anyway?

E.g. You want to solve

f1(x) = g1
f2(x) = g2
...

Why not optimise L(x) = (f1(x) - g1)^2 + (f2(x) - g2)^2 + ... with respect to x? If the minimum value is zero, then you are done; if it is greater than zero your original system does not have a solution.

If you are in the complex domain the changes needed are obvious.

V.

: -----Original Message-----
: From: r-help-bounces@stat.math.ethz.ch
: [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of John Janmaat
: Sent: Monday, 2 May 2005 12:48 AM
: To: r-help@stat.math.ethz.ch
: Subject: [R] Roots of quadratic system.
:
:
: Hello,
:
: I have a system of quadratic equations (results of a
: Hamiltonian optimization)
: which I need to find the roots for. Is there a package
: and/or function which
: will find the roots for a quadratic system? Note that I am
: not opimizing, but
: rather solving the first order conditions which come from a

: Hamiltonian. I am
: basically looking for something in R that will do the same
: thing as fsolve in
: Matlab.
:
: Thanks,
:
: John.
:
: ==============================================
: Dr. John Janmaat
: Department of Economics
: Acadia University
: Tel: 902-585-1461
:
: ______________________________________________
: R-help@stat.math.ethz.ch mailing list
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: PLEASE do read the posting guide!
: http://www.R-project.org/posting-guide.html
:



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon May 02 10:27:23 2005

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