eldo_user

Optimization
Optimization of Sweep Simulations
Using the OUTER Parameter To Specify Outer Design Parameters
By default, the parameters specified with a .PARAM command are inner design parameters.
Use the OUTER parameter in the .OPTIMIZE command to specify one or more parameters as
outer. The command syntax is:
.OPTIMIZE
+ [QUALIFIER=VALUE {, QUALIFIER=VALUE}]
+ [PARAM=LIST_OF_VARIABLES|*]
+ [RESULTS=LIST_OF_MEASURES|*]
+ [OUTER=LIST_OF_PARAMETERS|*]
There are some rules associated to the OUTER parameter:
• The order of the design variables specified within the list of parameters
LIST_OF_PARAMETERS has no precedence over the order specified in the netlist.
• The OUTER parameter is not considered when the OPSELDO_OUTER is active and all
the parameters are outer.
• The OUTER parameter specification is not valid for .STEP commands using the library
(corners) or temperature sweeps variants.
For example:
.OPTION OPSELDO_OUTER
.STEP PARAM P1
.STEP PARAM P2
Both parameters are outer parameters:
.STEP PARAM P1
.STEP PARAM P2
.OPTIMIZE OUTER=P2
The parameter P2 is the only candidate for the outer loop.
If the parameter of the .OPTIMIZE command is:
.OPTIMIZE OUTER=P2,P1
Then the parameter P1 would still be the outer-most within the outer loop as this is the order of
the .STEP PARAM commands.
A full optimization is performed for each outer design parameter.
Using the OPSELDO_OUTER Option To Specify Outer Design Parameters
It is also possible to reverse the behavior of optimization and sweep simulations using the
OPSELDO_OUTER option. When specified, the sweep on all design parameters becomes outer
with respect to the optimization process. An outer sweep is performed on the complete set of the
636
Eldo® User's Manual, 15.3