<@U01SBMJT5BP> Do you support python interface for...
# xycea
Amro Tork
06/08/2021, 6:23 PM@User Do you support python interface for sweeps and results in numpy?
e
Eric Keiter
06/08/2021, 6:24 PMThere is a python interface you can use to call Xyce. It is basically just the Xyce “C” interface, with a python wrapper. You can see some stuff about it in the Xyce source tree under Xyce/utils/XyceCInterface.
Eric Keiter
06/08/2021, 6:25 PMI should mention, I’m not sure it is developed enough to do sweeps conveniently.
Eric Keiter
06/08/2021, 6:25 PMBut if it isn’t we should work on that …
a
Amro Tork
06/08/2021, 6:25 PMJust to give you some hint what we do
Amro Tork
06/08/2021, 6:26 PMWe automate Analog design
e
Eric Keiter
06/08/2021, 6:26 PMThere is also a much newer python interface for plugging models written in python into Xyce. That is a separate effort that we call the “PythonModelInterface”
Eric Keiter
06/08/2021, 6:26 PMGot it.
a
Amro Tork
06/08/2021, 6:27 PMOne the steps that we do, is to run massive DC simulation to characterize the transistors at different sizes and voltages
Amro Tork
06/08/2021, 6:27 PMWe do that by DC sweep and parameter sweep
e
Eric Keiter
06/08/2021, 6:27 PMIf you want to do sweeps over lots of parameters, you might find the “DATA” specification useful.
a
Amro Tork
06/08/2021, 6:28 PMThanks for the insight
Amro Tork
06/08/2021, 6:28 PMI’ll give it a try.
e
Eric Keiter
06/08/2021, 6:28 PMThat allows you to specify a table of values. Each row of the table is a different sweep point.
Eric Keiter
06/08/2021, 6:28 PMAlso, you can “nest” sweeps via .STEP and .DC
a
Amro Tork
06/08/2021, 6:28 PMOh
Amro Tork
06/08/2021, 6:28 PMNice
Amro Tork
06/08/2021, 6:28 PMThe first one is nicer
e
Eric Keiter
06/08/2021, 6:29 PMIf using DATA, then you can change multiple things at once. Each column is for a different parameters (or DC value, potentially).
Eric Keiter
06/08/2021, 6:29 PMIt mimics the Hspice DATA statement.
a
Amro Tork
06/08/2021, 6:29 PMCould I pass this DATA as a csv file?
e
Eric Keiter
06/08/2021, 6:30 PMCurrently I don’t think it can take a csv file for input. But we might be able to add that.
Eric Keiter
06/08/2021, 6:30 PMV1 1 0 PAT (5 0 0n 1n 2n 5n b1010 R=0)R1 1 0 1.STEP data=test.DATA test+ V1:VHI V1:VLO V1:TD V1:TR V1:TF V1:TSAMPLE+ 5 1 0 1ns 2ns 5ns+ 6 2 5ns 2ns 1ns 10ns.ENDDATA.TRAN 0 50n.OPTIONS OUTPUT INITIAL_INTERVAL=0.5n.PRINT TRAN V(1).ENDEric Keiter
06/08/2021, 6:31 PMThat is a simple example from our test suite. .STEP is the command that tells Xyce to execute a sweep around whatever the analysis is. It refers to a table named “test”.
a
Amro Tork
06/08/2021, 7:13 PM@Eric Keiter thanks for sharing this..
Amro Tork
06/08/2021, 7:14 PMThe problem is that we sweep about 1Million iterations. I don't think it's easy to write that down in the spice netlist like this.
Amro Tork
06/08/2021, 7:14 PM1 Million iterations in a single run.
e
Eric Keiter
06/08/2021, 7:14 PMAh. That is a lot 🙂
Eric Keiter
06/08/2021, 7:14 PMhow many different parameters?
a
Amro Tork
06/08/2021, 7:15 PMNgspice do them in about 4h for a single transistor on 4 cores machine i9.
Amro Tork
06/08/2021, 7:15 PMCompiled with openmpi
Amro Tork
06/08/2021, 7:15 PMAnd all proper switches to make it use the right SSE and other good processor features.
Amro Tork
06/08/2021, 7:16 PMW, L , Ldiff, Vgs, Vds, Vbs, NF, Temp, Corners
Amro Tork
06/08/2021, 7:17 PMAnd we measure
Amro Tork
06/08/2021, 7:18 PMgm, Vth, Cgs, Cgd, Cgg, Cdd, ro, Vdsat
Amro Tork
06/08/2021, 7:21 PMI'll try to reproduce that setup in Xyce and keep you posted.
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