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Contradiction only without collect gen

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Helle there,

I'm currently having a hard time figuring out some odd behaviour.

when I run a test in a certain configuration, specman throws a contradiction and request a rerun with collect gen. When running with collect gen on, the whole test runs flawlessly as it should.

I'm fresh out of ideas after battling the for some time now. The irritating thing is:

when I constrain a struct in two bool flags as true, a method randomly picks one and resets it. 

If I manually reset all of them in the function, everything works as well.
Having both on true also works out fine.

resetting one of them in the method with the code below breaks a list somewhere in a completely different struct of the environment with a contradiction I cannot see. So using the "random resetter" I coded below, Specman goes nuts.

while list_of_desired_errors.count(it == TRUE) > 1
{
    message(FULL,"list_of_desired_errors.size() is still > 1, randomly resetting desired errors");
    var tmp_err_index_list : list of uint;
    tmp_err_index_list.clear();
    for each (err) using index (i) in list_of_desired_errors
    { 
        if err == TRUE
        { 
            tmp_err_index_list.add(i); 
        }; 
    };
    message(FULL,"tmp_err_index_list is: ",tmp_err_index_list);
    var t_uint : uint;
    message(FULL,"t_uint before random assignment is ",t_uint);
    gen t_uint keeping { it in tmp_err_index_list; };
    message(FULL,"t_uint after random assignment is ",t_uint);
    list_of_desired_errors[t_uint] = FALSE;
    message(FULL, "SINGLE_FRAME_ERR resetting error index ",t_uint); };
};

Ideas, anyone?

regards


Originally posted in cdnusers.org by SomeDude
Parents

  • Hi SomeDude,

    Ajeetha has a good question about which generation technology you are using and it is one that I have as well for you before I can offer you more advanced assistance. Are you using the current default generator (Pgen) or the new generator (IntelliGen)? If you are unsure, you can always type the command "show config gen" to see the results.

    One thing I would like to mention is that IntelliGen has been used on many customer projects successfully over the past year empowering customers with increased ease of use, solvability and performance. The ease of use features including improved contradiction handling and the new Generation Debugger GUI have proved very useful for many customers.

    I did take your example code and ran it however, I did not see any contradiction however, there may be other portions of your environment that are contributing to the contradiction. Could you clarify the below statement:


    when I constrain a struct in two bool flags as true, a method randomly picks one and resets it.


    Did you mean when you constrain two bool flags in a struct to be TRUE?

    Some other techniques for assistance with debug:
    -> (Pgen) Use the "show constraints" command to list all constraints acting on the field causing the contradiction
    -> (Pgen) Place a call to "specman("collect gen");" in procedural code (perhaps in a pre/post_generate() extension) at or near where the contradiction occurs rather than run with it on from the beginning of the simulation as this will localize the collection of generation information.
    -> (Pgen or IntelliGen) The "trace gen" command will output generator solving steps to the screen to assist in debug
    -> (IntelliGen) You can set a general breakpoint at or near where the contradiction occurs and then step into the generation results using the new Generation Debugger GUI by issuing the "gtree" command (there is no need for issuing a "collect gen" command in IntelliGen)

    I hope this helps. If you can replicate the issue you are seeing in a smaller testcase, please repost here however, I would also follow Ajeetha's suggestion and start a support request in parallel with the Cadence support team.

    regards,
    Corey


    Originally posted in cdnusers.org by cgoss
Reply

  • Hi SomeDude,

    Ajeetha has a good question about which generation technology you are using and it is one that I have as well for you before I can offer you more advanced assistance. Are you using the current default generator (Pgen) or the new generator (IntelliGen)? If you are unsure, you can always type the command "show config gen" to see the results.

    One thing I would like to mention is that IntelliGen has been used on many customer projects successfully over the past year empowering customers with increased ease of use, solvability and performance. The ease of use features including improved contradiction handling and the new Generation Debugger GUI have proved very useful for many customers.

    I did take your example code and ran it however, I did not see any contradiction however, there may be other portions of your environment that are contributing to the contradiction. Could you clarify the below statement:


    when I constrain a struct in two bool flags as true, a method randomly picks one and resets it.


    Did you mean when you constrain two bool flags in a struct to be TRUE?

    Some other techniques for assistance with debug:
    -> (Pgen) Use the "show constraints" command to list all constraints acting on the field causing the contradiction
    -> (Pgen) Place a call to "specman("collect gen");" in procedural code (perhaps in a pre/post_generate() extension) at or near where the contradiction occurs rather than run with it on from the beginning of the simulation as this will localize the collection of generation information.
    -> (Pgen or IntelliGen) The "trace gen" command will output generator solving steps to the screen to assist in debug
    -> (IntelliGen) You can set a general breakpoint at or near where the contradiction occurs and then step into the generation results using the new Generation Debugger GUI by issuing the "gtree" command (there is no need for issuing a "collect gen" command in IntelliGen)

    I hope this helps. If you can replicate the issue you are seeing in a smaller testcase, please repost here however, I would also follow Ajeetha's suggestion and start a support request in parallel with the Cadence support team.

    regards,
    Corey


    Originally posted in cdnusers.org by cgoss
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