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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,

    Thanks for clarifying what you are seeing. Do you see a contradiction in the code example that you have displayed? I have tried to replicate a contradiction on my side using SPMN 6.2-s003 using several hundres seeds however, I could not (I limited the list_of_desired_errors size to 7 and had to wrap some context around your example).

    I am not sure if you have code that processes each of these errors as you reset the bools however, I am curious as to why you would use a procedural loop to perform this task considering that similar functionality can be implemented using pure generation. Consider the example below:

    <'
    extend sys {

    // testwriter can constrain the error location
    error_location: uint;
    keep soft error_location in range [0..6];

    // testwriter can constrain whether frames are errored or not
    errored_frame: bool;

    list_of_desired_errors[7]: list of bool;

    keep for each in list_of_desired_errors {
    soft it == FALSE; // default no errors
    }; // keep for each i...

    // if frame is to be errored, pick a single random error location
    keep errored_frame => list_of_desired_errors[error_location] == TRUE;

    }; // extend sys

    '>

    As coded above, we are only targeting one location however I have coded random error generation schemes many times in the past that inserts any number of faults in any number of locations, allowing complete control to the testwriter to constrain the behaviour from the testcase.

    Would something like this work in your situation?

    regards,
    Corey


    Originally posted in cdnusers.org by cgoss
Reply

  • Hi SomeDude,

    Thanks for clarifying what you are seeing. Do you see a contradiction in the code example that you have displayed? I have tried to replicate a contradiction on my side using SPMN 6.2-s003 using several hundres seeds however, I could not (I limited the list_of_desired_errors size to 7 and had to wrap some context around your example).

    I am not sure if you have code that processes each of these errors as you reset the bools however, I am curious as to why you would use a procedural loop to perform this task considering that similar functionality can be implemented using pure generation. Consider the example below:

    <'
    extend sys {

    // testwriter can constrain the error location
    error_location: uint;
    keep soft error_location in range [0..6];

    // testwriter can constrain whether frames are errored or not
    errored_frame: bool;

    list_of_desired_errors[7]: list of bool;

    keep for each in list_of_desired_errors {
    soft it == FALSE; // default no errors
    }; // keep for each i...

    // if frame is to be errored, pick a single random error location
    keep errored_frame => list_of_desired_errors[error_location] == TRUE;

    }; // extend sys

    '>

    As coded above, we are only targeting one location however I have coded random error generation schemes many times in the past that inserts any number of faults in any number of locations, allowing complete control to the testwriter to constrain the behaviour from the testcase.

    Would something like this work in your situation?

    regards,
    Corey


    Originally posted in cdnusers.org by cgoss
Children
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