Hi,

I need an answer to a simple question.

I need to define constraints such as f(x) in [a,b].

Must I separe it into two different constraints f(x)>=a and f(x)<=b ?

Does Ibex consider it to be the same as f(x)=[a,b] ? Even though it is mathematically different, Ibex seems to do the same (considering lots of tests I made).

Thanks !

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zenno

Thu, 07/17/2014 - 10:43

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## Hi Etienne,

Hi Etienne,

Indeed, you don't need to separate f(x) in [a,b] into two constraints f(x)>=a and f(x)<=b because Ibex accepts interval constants in expression. So f(x)=[a,b] is correct. You can even directly use the CtcIn contractor instead of CtcFwdBwd. Here are the two variants:

With CtcFwdBwd:

With CtcIn:

In both cases the display is:

before contraction: ([-inf, inf])

after contraction: ([1, 2])

Gilles