Re: Compact formulation of array of constraints
- To: mathgroup at smc.vnet.net
- Subject: [mg132221] Re: Compact formulation of array of constraints
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Mon, 20 Jan 2014 03:59:24 -0500 (EST)
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With "patterns": expr = Sqrt[x[2]^2] + Sqrt[x[3]^2]; Assuming[Thread[Cases[Variables[expr], x[_]] > 0], Simplify[expr]] x[2] + x[3] Assuming[Cases[Variables[expr], x[n_] -> (x[n] > 0)], Simplify[expr]] x[2] + x[3] Bob Hanlon On Sun, Jan 19, 2014 at 2:55 AM, Yi Wang <tririverwangyi at gmail.com> wrote: > For this example, yo can do > > Apply[And, (x[#] >= 0) & /@ Range[5]] > > For example, > > Assuming[(x[#] >= 0) & /@ Range[5], Simplify[Sqrt[x[2]^2]]] > > On the other hand, AFAIK patterns do not work in this situation. > > > Dear All, > > > > > > > > How can one formulate the set of constraints > > > > > > > > x[1] >= 0, x[1] >= 0, x[2] >= 0, x[3] >= 0, x[4] >= 0, x[5] >= 0 > > > > > > > > by using a compact form? > > > > > > > > Thanks in advance, > > > > > > > > Paul > >