Scaling
From Glossary
Changing the units of measurement, usually for the numerical stability of an algorithm. The variables are transformed as where The diagonal elements are the scale values, which are positive: Constraint function values can also be scaled. For example, in an LP, the constraints can be scaled by where such that (This affects the dual values.) Some LP scaling methods simply scale each column of A by dividing by its greatest magnitude (null columns are identified and removed).
Example  A column scaling  A row scaling  



Another method is logarithmic scaling, which scales by the logarithm of the greatest magnitude. More sophisitcated methods are algorithmic, taking both row and column extremes into account.