How to only create a dynamic array and not do randomize on 'rand int a[ ]' in sequence item?

[enchanter]

I have a dynamic array in sequence item as below:

 

rand int array_size;

rand int a [];

 

constraint c_order {solve array_size before a;};

constraint c_size { a.size() == array_size;};

 

 

In some tests, I hope to only create the array according to the randomized value of array_size but not do randomize on the value of it. Is there any way I can do that?

 

 

[dave_59]

Why is it you don't want the elements of array a to be randomized? If it is because you want the array values to be 0, then just add that constraint - foreach(a) a == 0;

[enchanter]

Why is it you don't want the elements of array a to be randomized? If it is because you want the array values to be 0, then just add that constraint - foreach(a) a == 0;

 

Most time, I expect random value to test DUT. But sometimes I hope to get some simple patterns to test my verification environment, for example I expect the size is random but the value are constant or in/decreasing etc.

 

If I use foreach, could I turn it off when I expect random value?

[tudor.timi]

You can put the foreach constraint that dave_59 suggested in a separate constraint block and disable that using constraint_mode(0). Ex;
 

// somewhere in your class
constraint fixed_vals_c {
  foreach (a[i])
    a[i] == 0;
}

// somewhere where you randomize
some_obj.fixed_vals_c.constraint_mode(0);
some_obj.randomize();  // will gen random vals for array