Stats

  • Locked Locked
  • Replies 9
  • Subscribers 126
  • Views 16844
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Anyone done trim-and-sim with Monte Carlo?

swdesigner

Is it possible to run a monte-carlo simulation with two extractions per sample?

The tool generates a set of values for the variables (process/mismatch) per sample. The question is, can I, for this sample, take a measurement, based on that measurement, set some user-variables to non-default values and run another sim to take another measurment (maybe at a different temperature)?

This is what happens in the real world on silicon - you're going to trim your circuit at room-temp and look at it at different temps regardless of what the process/mismatch are for a particular unit.

How difficult is this? Can we add such capability soon?

 

Thanks

Parents

  • It can be (also) done by running a pair simulations for each monte carlo run. The first simulation would be a "trim" simulation to find out  the variable values. The second sim would be  the real sim run with these values.

    The key is that you use exactly same "seed" and "run" number for each "trim" and "sim" pair. As long as seed/run numbers are the same, the netlist would be identical for each pair of sims.

    This can be a lot of manual labor, but it might be possible to automate it with an oceanScript. You can have an outer for loop that increments run numbers. Within this loop, you run 2 monte carlo analyses in sequence, each with number of runs=1 and starting run=loop variable. You process the results out of the first monte Carlo and then set your variables etc before you start your second monte carlo.

    You probably got a general idea. However you may have work on getting the ocean-script code right.

     

Reply

  • It can be (also) done by running a pair simulations for each monte carlo run. The first simulation would be a "trim" simulation to find out  the variable values. The second sim would be  the real sim run with these values.

    The key is that you use exactly same "seed" and "run" number for each "trim" and "sim" pair. As long as seed/run numbers are the same, the netlist would be identical for each pair of sims.

    This can be a lot of manual labor, but it might be possible to automate it with an oceanScript. You can have an outer for loop that increments run numbers. Within this loop, you run 2 monte carlo analyses in sequence, each with number of runs=1 and starting run=loop variable. You process the results out of the first monte Carlo and then set your variables etc before you start your second monte carlo.

    You probably got a general idea. However you may have work on getting the ocean-script code right.

     

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.