eldo_user

Running Parametric Analyses
Altering Netlist Data For Simulation Reruns
Altering Netlist Data For Simulation Reruns
You can rerun simulations with a modified netlist using the .ALTER command. An alter block
consists of Eldo element, subcircuit, command, and comment statements. The alter block ends
with the next .ALTER or .END command. All Eldo statements in an alter block are backsubstituted
in the original netlist except for some commands which are always added to the
netlist with no substitution attempted. The circuit_name.chi ASCII log file contains a trace of
all modifications made.
The way Eldo processes a netlist with .ALTER blocks is as follows:
1. Eldo reads the netlist up to the first .ALTER statement and performs the analyses. This
is the first simulation run.
2. Eldo then reads the block of statements between the first .ALTER and .END (or another
.ALTER) statements.
3. Eldo modifies the netlist using these alter block statements.
4. Eldo reruns the simulation with the modified netlist.
For multiple .ALTER blocks, the initial netlist is always as the reference to be altered, not the
result of the previous .ALTER command. If there is an error in a .ALTER block, it will be
skipped and the next .ALTER block will be used.
To run a specific .ALTER block without first running the main netlist, invoke Eldo with the
-alter argument together with the corresponding name or index of the alter block required.
Specifying an index of 0 means the nominal run without any alters.
Multiple indexes can be specified without separators. When Eldo identifies -alter, it interprets
the following arguments as indexes until another argument is found (beginning with “-”). For
example:
eldo foo.cir -alter 2 5 10 11 12 13 20 21 22
Tip
See the “.ALTER” command and the “-alter” command-line argument in the Eldo
Reference Manual.
Removing .EXTRACT Statements from a Simulation Rerun. . . . . . . . . . . . . . . . . . . . . 299
Controlling Alter Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
.ALTER Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
298
Eldo® User's Manual, 15.3