[R] solving system of equations involving non-linearities
Ravi Varadhan
rvaradhan at jhmi.edu
Thu Aug 6 16:29:58 CEST 2009
You have two options:
1. The `BBsolve' function in the "BB" package to solve this system of 3 equations.
2. Try `nleqslv' function in the "nleqslv" package.
These would work even if the residual is not zero.
Hope this helps,
Ravi.
____________________________________________________________________
Ravi Varadhan, Ph.D.
Assistant Professor,
Division of Geriatric Medicine and Gerontology
School of Medicine
Johns Hopkins University
Ph. (410) 502-2619
email: rvaradhan at jhmi.edu
----- Original Message -----
From: Werner Wernersen <pensterfuzzer at yahoo.de>
Date: Thursday, August 6, 2009 7:56 am
Subject: [R] solving system of equations involving non-linearities
To: r-help at stat.math.ethz.ch
> Hi,
>
> I would appreciate if someone could help me on track with this problem.
>
> I want to compute some parameters from a system of equations given a
> number of sample observations. The system looks like this:
>
> sum_i( A+b_i>0 & A+b_i>C+d_i) = x
> sum_i( C+d_i>0 & C+d_i>A+b_i) = y
> sum_i( exp(E+f_i) * ( A+b_i>0 & A+b_i>C+d_i) = z
>
> A, C, E are free variables while the other letters represent values
> given from sample observations. The equations involve counts of the
> number of fulfilled conditions and therefore non-linearities.
> Furthermore, since I have many observations i, the equations will
> unlikely hold exactly and solving will require some closeness measure
> like the sum of the squared deviations or so.
>
> Is there any function in R suitable for solving this problem?
>
> Thanks so much for your help,
> Werner
>
>
>
>
>
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