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 APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" 

Last post Fri, Feb 3 2012 2:21 AM by Andrew Beckett. 8 replies.
Started by Aldo2 19 Oct 2011 05:08 AM. Topic has 8 replies and 5765 views
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  • Wed, Oct 19 2011 5:08 AM

    • Aldo2
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    APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Hello!

    How can I avoid the following error running an aps-pss with mmsim 10.1?

    Error found by spectre during periodic steady state analysis `pss'.
        ERROR: ZERO DIAG reordering in Matrix factor
        ERROR: ZERO DIAG reordering in Matrix factor
        ERROR: ZERO DIAG reordering in Matrix factor
        ERROR: ZERO DIAG reordering in Matrix factor
        ERROR: ZERO DIAG reordering in Matrix factor

    ...

    Thank you

    Aldo

    • Post Points: 20
  • Wed, Oct 19 2011 5:19 AM

    Re: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Aldo,

    I would suggest you log a service request for this issue. It looks like CCR 941065 which is to do with the beat frequency calculated by the GUI not matching the actual beat frequency due to rounding error and thus getting an inaccurate match (probably looking at the analysis statements in the input.scs would reveal this). You could try typing "autofund=yes" into the Additional Parameters field at the bottom of the PSS options form - but this is very much a wild guess - it may not be this problem at all. Without seeing the data, it's very hard to be sure (there are very few reports of this precise error message).

    So that's why a service request makes sense - we can then take a more detailed look at the data.

    Regards,

    Andrew.

    • Post Points: 35
  • Wed, Oct 19 2011 6:23 AM

    • Aldo2
    • Top 200 Contributor
    • Joined on Mon, Aug 29 2011
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    Re: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Thank you Andrew!

    Can I attach your answer to the service request?

    Best Regards

    Aldo

    • Post Points: 20
  • Wed, Oct 19 2011 6:30 AM

    Re: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Aldo,

    Of course!

    Andrew.

    • Post Points: 5
  • Thu, Feb 2 2012 7:46 AM

    • matzowicz
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    • Joined on Mon, Jan 31 2011
    • Posts 2
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    Re: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Hello Mr. Beckett,

     I have experienced the same problems as Aldo:

    When using the spectre-pss everything works fine, when I switch to aps-pss I will get the error message:

    ERROR: ZERO DIAG...

    (Error message after finishing the third iteration.)

     Has anything happened since Aldo posted the request?

    (The autofund=yes did not fix the problem.)

     

    ****************************************************
    Periodic Steady-State Analysis `pss': fund = 200 MHz
    ****************************************************
    Trying `homotopy = gmin' for initial conditions.
    Zero diagonal found in Jacobian at `I1125.I81:out_flow' and `I1125.out1'.
    Zero diagonal found in Jacobian at `I1125.I81:out_flow' and `I1125.out1'.
    Zero diagonal found in Jacobian at `I1125.I81:out_flow' and `I1125.out1'.
    Zero diagonal found in Jacobian at `I1125.I81:out_flow' and `I1125.out1'.
    Zero diagonal found in Jacobian at `I1125.I81:out_flow' and `I1125.out1'.
    Trying `homotopy = source' for initial conditions.
    Trying `homotopy = dptran' for initial conditions..
    Zero diagonal found in Jacobian at `net035' and `net035'.
    Zero diagonal found in Jacobian at `net035' and `net035'.
    Zero diagonal found in Jacobian at `net035' and `net035'.
     

     I think the problem is hidden somewhere in the above lines, which aps shows, but spectre does not (copied from outputLog).

    Regards,

    matzowicz

    • Post Points: 35
  • Thu, Feb 2 2012 10:49 AM

    • Tawna
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    RE: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply
    Hi Matzowicz,
     
    I suggest filing a Service Request at http://support.cadence.com .  There are a number of things that can cause this
    error message.  For example, it could be from dangling inductors in the circuit or a bug in the software (and a number of other things
    as well).   Please check the warnings in the spectre output log for clues ... they contain valuable information.
     
    It always helps to post what subversion of Spectre/APS that you are using.  You can find this near the
    top of the spectre.out logfile.  Or by typing in an xterm:
    spectre -W
     
    best regards,
    Tawna
    Best regards, Tawna Wilsey Staff Support AE, Global Customer Support Cadence Design Systems, Inc.
    • Post Points: 5
  • Thu, Feb 2 2012 12:04 PM

    • Tawna
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    • Snohomish, WA
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    RE: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply
    Hi Matzowicz,
     
    It is possible that you've run into a recent issue reported in Solution

    11769272 (COS) Error:  Zero diagonal found in Jacobian

    The issue is fixed in MMSIM 11.1 ISR4.  You may download the latest ISR from  http://downloads.cadence.com .

    best regards,
     
    Tawna
    Best regards, Tawna Wilsey Staff Support AE, Global Customer Support Cadence Design Systems, Inc.
    • Post Points: 20
  • Fri, Feb 3 2012 12:20 AM

    • matzowicz
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    • Joined on Mon, Jan 31 2011
    • Posts 2
    • Points 55
    Re: RE: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

     Hi Tawna,

    thanks for the quick reply.

     (I'm using MMSIM 10.1)

     I think I was imprecise formulating the problem:

    The above warnings arised with aps but not with spectre when trying to find the dc-solution. Both simulators find a DC-operating point and start to simulate.

     I have used tstab so that the signals can settle.

    After the second iteration, the pss aborts.

    ...

        pss: time = 4.625 ns    (72.5 %), step = 650.1 fs      (13 m%)
        pss: time = 4.876 ns    (77.5 %), step = 1.407 ps    (28.1 m%)
        pss: time = 5.128 ns    (82.6 %), step = 3.777 ps    (75.5 m%)
        pss: time = 5.376 ns    (87.5 %), step = 2.209 ps    (44.2 m%)
        pss: time = 5.625 ns    (92.5 %), step = 3.092 ps    (61.8 m%)
        pss: time = 5.876 ns    (97.5 %), step = 964.7 fs    (19.3 m%)
    Conv norm = 69e+03, max dV(I1151.hold) = -2 V, took 55.62 s.


    Error found by spectre during periodic steady state analysis `pss'.
        ERROR: ZERO DIAG reordering in Matrix factor
    ...(plenty of repetitions here)
        ERROR: ZERO DIAG reordering in Matrix factor

    Analysis `pss' was terminated prematurely due to an error.

    I think that there is a problem when the simulator compares the new simulation results (2nd run) with the old ones (from the 1st run).

    The pss runs perfectly fine with spectre, but it's too slow. (I have to use the pss, otherwise the results will be to imprecise.)

    A wonderful day,

     Matzowicz

     

    • Post Points: 20
  • Fri, Feb 3 2012 2:21 AM

    Re: RE: APS-PSS error: "ERROR: ZERO DIAG reordering in Matrix factor" Reply

    Hi Matzowicz,

    It's still possible that the problems are related - since the solution that Tawna mentioned had similar symptoms and was also a difference between APS and standard spectre. I would suggest trying the hotfix that is mentioned in the solution and if that doesn't work, please log a service request as she suggested.

    Regards,

    Andrew.

    • Post Points: 5
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Started by Aldo2 at 19 Oct 2011 05:08 AM. Topic has 8 replies.