eldo_user

.SAVE END in Combination with .RESTART
Setting Up An Analysis
Saving and Restarting Transient Simulations
It is possible to run a transient simulation and save the final state of the run. Thereafter, it is
possible to restart the transient simulation from the time the last simulation was ended. To
achieve this, use the .SAVE command in combination with the END parameter.
To restart the simulation, the circuit description file must be modified. The original .SAVE
command must be removed and the .TRAN command must be modified to reflect the new end
time. Furthermore, a .RESTART command must be included in the circuit description file:
.RESTART
Using the above procedure, the simulation will produce a new binary output file (.wdb file) that
contains data starting from the end of the last simulation. To concatenate old and new .wdb files,
the old .wdb file should be renamed to, for example, tmpfile and the previous .RESTART
command modified as follows:
.RESTART FILE=
The system then concatenates the old .wdb file data with the new .wdb data.
More Sophisticated .SAVE and .RESTART Procedures
The complete .SAVE syntax shown in the line below includes provision to save the simulation
state either periodically or at predefined times and/or temperature or sweep (STEP) parameter
conditions:
.SAVE [fname] {DC|END|TIME=value} [REPEAT] [TEMP=value] [STEP=value]
It is possible to save the result of the simulation periodically (with REPEAT), to save the run for
a particular temperature (with TEMP) or for a particular swept parameter (with STEP).
In each case, the rule to restart the simulation from a predefined state is the same; to restart the
simulation, the .RESTART command needs to be added to the circuit description file. The
.SAVE commands contained therein should be removed.
The transient simulation parameters in the .TRAN command may also need to be modified to
reflect the new desired simulation time stop.
Save and Restart Example
1. Run a simulation on the netlist file restart.cir containing the following command to save
simulation information at 400ns to file test.sav:
.SAVE test.sav time=400ns
2. Rename the generated simulation results file restart.wdb as test_previous.wdb.
3. Relaunch Eldo with the following command in the netlist:
Eldo® User's Manual, 15.3 221