Re: [sv-ec] soft constraints and .size randomization

i've registered it as:
http://www.verilog.org/mantis/view.php?id=5215


W dniu 2/9/2015 4:22 PM, Mark Strickland (mastrick) pisze:
> Ah, thanks.  I was focusing on the wrong part of your question. 
>  Essentially your question is whether if the only constraints on a 
> variable are "discarded" soft constraints, that variable is considered 
> "unconstrained".  It does seem like a sentence clarifying that would 
> be good.
>
> Mark
>
> From: Daniel Mlynek <danielm@aldec.com.pl <mailto:danielm@aldec.com.pl>>
> Date: Monday, February 9, 2015 10:09 AM
> To: Mark Strickland <mastrick@cisco.com <mailto:mastrick@cisco.com>>
> Cc: "sv-ec@eda.org <mailto:sv-ec@eda.org>" <sv-ec@eda.org 
> <mailto:sv-ec@eda.org>>
> Subject: Re: [sv-ec] soft constraints and .size randomization
>
> This is special case when is smth is random is decided basing on 
> constraints.
> Array size is random when .size is used in constraints.
> All other variables are randomized if they are declared as random or 
> used as argument to randomize method or function.
>
>
> DANiel
>
> W dniu 2/9/2015 3:53 PM, Mark Strickland (mastrick) pisze:
>> Daniel,
>>
>> I would think it would have to be "remain to be random but constrain 
>> on it should be removed".  Do you see text in the LRM that could 
>> suggest soft constraints can control whether randomization happens?
>>
>> Mark
>>
>> From: Daniel Mlynek <danielm@aldec.com.pl <mailto:danielm@aldec.com.pl>>
>> Date: Monday, February 9, 2015 6:52 AM
>> To: "sv-ec@eda.org <mailto:sv-ec@eda.org>" <sv-ec@eda.org 
>> <mailto:sv-ec@eda.org>>
>> Subject: [sv-ec] soft constraints and .size randomization
>>
>> See example:
>>
>>     class D;
>>         rand bit[2:0] arr[]='{1,2};
>>        rand int a=1,b=10;
>>         constraint con1 { soft arr.size < a && arr.size > b; }
>>
>>     endclass
>>
>>     D d = new;
>>
>>     module top;
>>         initial repeat(10) begin
>>                //d.arr = new[5];
>>            // d.con1.constraint_mode(0); d.con2.constraint_mode(0);
>>             assert(d.randomize() with {a<b;}) else
>>     $fatal("Randomization failed.");
>>             $display("%p",d.arr);
>>         end
>>     endmodule
>>
>>
>> LRM is not clear what should happen in such case.
>> "arr" size should not be randomized because soft constraints con1 is 
>> discarded by inline constraint.
>> or
>> "arr" size should remain to be random but constrain on it should be 
>> removed
>>
>>
>>
>> DANiel
>>
>>
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