Re: solving equation system



TG wrote:
Sorry for the poor explanation. I'm trying to put it clear now.

i've got A and B. I'm looking for X. I made a mistake in my equation
:-/

It's more like :

A.X - B >= O

Well, maybe it will be much more simple if I explain the underlying
problem :

I have an array of N dimensions (generally 2).
- A first calculation gives me a set of integer coordinates inside this
array, which I will call the point W.
- After several other calculations, I've got a set of coordinates in
this N dimensional space that are floating values, and not bound to the
limits of my original N-array. This is the point L.

What I want to do is to translate the point L along the vector LW in
order to get a point L' which coordinates are inside the original
N-dimensional array. Then it will be easy to get the closest integer
coordinates from L'.

I see. You have a simple linear programming problem. These can be
tricky in general. Because you only have one variable, it's probably
ok to use brute force. Try this:

given X, A, and B:

E = A*X-B
C = numpy.where(E<0,B/A,X)
X = min(C)

This assumes that you've designed the problem such that B/A would be
less than X where A*X-B<0 (if the opposite were true then of course
you'd need max(C)).


Carl Banks

.



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