**keywords:**

`USE-SCALING-FACTORS`

`USE-CONSTRAINT-SCALING-FACTORS`

`USE-VARIABLE-SCALING-FACTORS`

`GET-SCALING-FACTORS`

`PRINT-SCALING-FACTORS`

It may happen that a user's problem uses variables or general
constraints
whose normal numerical values are wildly different in
magnitude. This poor scaling can cause difficulties for *
LANCELOT*. As a precaution, the user may ask that the problem be
(implicitly) rescaled before the optimization commences. The scaling
algorithm used is not foolproof and should only really be used if the
user encounters difficulties when solving the problem unscaled. It is
frequently far better for the user to rescale his or her problem him
or herself, so that all the variables have roughly the same value at a
``typical point''; the same advice hold for constraint functions.

*LANCELOT*'s scaling algorithm is invoked by the `
GET-SCALING-FACTORS` keyword. This produces appropriate scale factors.
These values may be printed by specifying the `
PRINT-SCALING-FACTORS` keyword and are applied to the problem during
the optimization when `USE-SCALING-FACTORS` is specified. The
scale factors are applied to the general constraints
and variables
separately when the `USE-CONSTRAINT-SCALING-FACTORS` and `
USE-VARIABLE-SCALING-FACTORS` keywords are, respectively, included.
The default is that no scaling is performed.