dist inside set that is not consecutive

Question

Obviously you can write constraints that give a weight to a consecutive range of values:

rand int value;
constraint dist_name {value dist { [0:5] :/ 50, [6:23] :/ 50}; }

But how could one go about creating a weighted distribution for a non-consecutive set of values?

Something like:

rand int value;
constraint dist_name {value dist { inside {0,4,7} :/ 50, inside {2,3,9}  :/ 50}; }

Obviously without some kind of "inside" operator, the {} are treated as concatenation... is there a way?

Answer 1

Solution

ce_2015

Full Access

41 posts

April 24, 2019 at 6:41 am

In reply to ce_2015:

This post:

https://verificationacademy.com/forums/systemverilog/distributed-weightage-constraint

gave me the idea to have another variable that is restricted to the amount of "sets" of numbers you want, then set the distribution on that variable rather than the variable that belongs to one of the sets:

rand bit [1:0] selector; // Range of variable values to represent number of sets
rand int value;
constraint set_dist  {selector dist { 2 := 20, 1 := 30, 0 := 50 };}
constraint dist_name {selector == 2 -> value inside {1,5};
                      selector == 1 -> value inside {0,4,7}; 
                      selector == 0 -> value inside {2,3,9}; }

Languages & Standards

Methodologies

Techniques & Tools

Universal Verification Methodology (UVM)

Featured Courses

Additional Courses

Formal-Based Techniques

Analog/Mixed Signal

UVM Forum

SystemVerilog Forum

Coverage Forum

Additional Forums

Implementation Patterns

Specification Patterns

Pattern Resources

UVM Cookbook

Coding Guidelines & Deployment

Coverage Cookbook

Upcoming & Featured Events

On Demand Seminars

Recording Archive

Mentor Training Center

Mentor Learning Center

Blog & News

Verification Horizons Publication

About Us

Training

Solution