"gmethod" option in Spectre

[hamidrezah]

Dear Cadence experts:

Would anyone please tell me what "gmethod" option does in Spectre?

I have a circuit that under certain design variable settings, produces
unwanted DC operating point result (notice it converges but the result
it produces is far different than expected). When I set "gmethod=both"
the circuit produces expected results for all design variable
settings. But I need to know what "gmethod=both" does to my
simulation?

Any hint/remark is very much appreciated.

Thank you.

Regards,

Hrh

 

[Andrew Beckett]

On 04/23/12 11:55, hamidrezah wrote:

Dear Cadence experts:

Would anyone please tell me what "gmethod" option does in Spectre?

I have a circuit that under certain design variable settings, produces
unwanted DC operating point result (notice it converges but the result
it produces is far different than expected). When I set "gmethod=both"
the circuit produces expected results for all design variable
settings. But I need to know what "gmethod=both" does to my
simulation?

Any hint/remark is very much appreciated.

Thank you.

Regards,

Hrh

I believe (from looking at the "spectre -h options" output) that this
only affects how conductances are stamped into the matrix during some of
the homotopy methods used in difficult convergence - but I believe the
effect is removed once convergence is reached. To be sure, you should
contact Cadence Customer Support at http://support.cadence.com
and ask there.

Andrew