Characteristic values to scale continuous design variables


  • Alias: cdv_scales

  • Arguments: REALLIST

  • Default: vector values = 1 . (no scaling)


Each real value in scales is a nonzero characteristic value to be used in scaling each continuous design variable. They only have effect when the associated method specifies scaling.

This keyword is required for scale_types of <tt>’value’</tt> and optional for <tt>’auto’</tt> and <tt>’log’</tt>. When specified in conjunction with log, scale values are applied prior to the logarithm, to permit log scaling of strictly negative design variables.

If a single real value is specified it will apply to all continuous design variables. Otherwise, a scale value must be specified for each continuous design variable.

Usage Tips:

When scales are specified, but not scale_types, the scaling type is assumed to be ‘value’ for all continuous design variables.

Use scale values of 1.0 to selectively avoid scaling a subset of the variables.

Scaling for linear constraints is applied after any continuous variable scaling.

See the scaling information under specific methods, e.g., method-*-scaling for details on how to use this keyword.


Two continuous design variables, one scaled by the characteristic value 4.0, the other log-scaled without additional value scaling

continuous_design = 2
  initial_point    -1.2      1.0
  lower_bounds     -200      0.001
  upper_bounds      200      2.0
  descriptors       'x1'     "x2"
  scale_types = 'value' 'log'
  scales = 4.0 1.0