x1*(A1+B1+C1)-A1=0.
This will give you 12 equations in 9 unknowns. For this, "lm" will give you the least squares solution. If the system has a single unique solution, "lm" will find it and report a residual standard deviation equivalent to round-off error. To do this, it helps to make a "data.frame", described, e.g., in "An Introduction to R" available via help.start().
spencer graves
Olivier ETERRADOSSI wrote:
Dear R-gurus,
being very new to R, (as well as lazy and not too smart !) I have some problems (and get lost in the docs) trying to write something to find the 9 values (A1,B1,C1,A2,B2,C2....C3) which are solutions of a 12 equations system of the form :
> x1-(A1/(A1+B1+C1)) = 0
> y1-(B1/(A1+B1+C1))= 0
> z1-(C1/(A1+B1+C1)) = 0
> 3 same equations with subscript 2
> 3 same equations with subscript 3
> A1*K+A2*L+A3*M = S
> B1*K+B2*L+B3*M = T
>C1*K+C2*L+C3*M = U
where x1,y1,.....y3,z3, K,L,M,S,T and U are known.
Can any of you give me some light to begin ? I guess something already exists but can't find it...
Thanks a lot for any hint.
Olivier
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