List Scaling Factors

Type

Selection

Range

The settings listed below

Default

Off

This option controls whether AIMMS should print the scaling factors, found by one of its scaling algorithms, to the listing file. Possible values are:

  • Off

  • Automatic

  • Individual

  • Symbolic

The scaling algorithm used by AIMMS is controlled by the option Scaling Algorithm. The Optimization based algorithm scales variables and constraints at the symbolic level. This is illustrated by the following example: if the model contains the variable X(i), with i in {1,…,5}, then the scaling factor found for X(i) will be the same for all i, so the scaling factor found for X(1) will be the same as for X(2) to X(5). The other two scaling algorithms, Iterative and Combination, find scaling factors at the individual (column and row) level. Using the same example, the scaling factors found for X(i) might be different, so the scaling factor found for X(1) might be different than the one found for X(2).

The ‘Symbolic’ setting is only available if the Scaling Algorithm option has been set at ‘Optimization Based’, or at ‘Automatic’ and (only) the Optimization Based algorithm is used. The ‘Individual’ setting is available for all scaling algorithms, including the Optimization based algorithm.

At the ‘Automatic’ setting AIMMS will select ‘Symbolic’ if the Scaling Algorithm option has been set at ‘Optimization Based’, or at ‘Automatic’ and (only) the Optimization Based algorithm is used. AIMMS will select ‘Individual’ otherwise.

Note

  • This option is only used if the option Scale Model has been switched on.

  • The scaling factors will also be printed in the listing file if the Scale Model inside the Math Program Inspector is used and this option is set to ‘Automatic’ or ‘Symbolic’.

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