[R] .Internal(optim)

Thomas Lumley tlumley at u.washington.edu
Thu Jul 10 17:37:04 CEST 2003

On Wed, 9 Jul 2003, Spencer Graves wrote:

> I haven't used optim enough to know, but simular functions ostensibly
> with box constraints would still test values outside the box and quite
> if it got an NA or possibly Inf.  I've had good luck transforming the
> inputs to remove constraints.  For example, if you need x > 0, then

optim() doesn't test values outside the box (even using finite difference
approximations for derivatives), but it does test values on the boundary.

Box constraints are for x>=0, which you can't get with transformations.
For x>0 transformations may well be indicated.


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