Multi Dimensional Dynamic Array Constraint support Issue in System Verilog/UVM

Hello Mahesh.

Dynamic arrays do not get allocated by randomisation, so based on the small snippet of code you've shared, the array_of_frames will still be empty after the randomize() call.

I assume you are allocating the array before calling randomize(). What are the dimensions that you've set?

You also appear to have missed some constraints on the size of array_of_frames, there is nothing linking that to the other rand variables in your constraints.

If you can share a runnable example that show the error, it'll be a lot easier to help you. You should also state which simulator version you're using.

Hi Stephen,

     I've missed some logic in the previous post. Below is the complete example in system verilog;

program main();

    class base;

       rand int array_of_frames[][][];

       rand int frame_height;

       rand int frame_width;

       rand int no_of_frames;

       constraint no_of_frames_c { no_of_frames>1;no_of_frames<3;}

       constraint frame_height_c { frame_height>10;frame_height<20;}

       constraint frame_width_c {frame_width>1;frame_width<100;}

       constraint array_of_frames_c {       

             array_of_frames.size == no_of_frames;  

             foreach (array_of_frames[i]) {           array_of_frames[i].size == frame_height;          }  

            foreach (array_of_frames[i,j]) {            array_of_frames[i][j].size == frame_width;      }  

      }

  function void post_randomize();

   for(int i=0; i<array_of_frames.size; i++) begin    

      for(int j=0; j<array_of_frames[i].size; j++) begin          

         for(int k=0; k<array_of_frames[i][j].size; k++) begin              

               $write("0x%x ", (array_of_frames[i][j][k] & 32'hFF));      

        end        

       $display(" ");  

     end      

   $display(" ");  

 end

endfunction

endclass

base b0 = new();

initial  

void'(b0.randomize());

 endprogram

After simulation I've been observed the below message from irun.log;

void'(b0.randomize());
|
ncsim: *W,SVRNDF (./multi_ddynamic_array.sv,53|19): The randomize method call failed.
Observed simulation time : 0 FS + 1
ncsim: *W,RNDOCS: These constraints contribute to the set of conflicting constraints:

constraint frame_height_c { frame_height>10;frame_height<20;} (./multi_ddynamic_array.sv,19)
foreach (array_of_frames[i]) { (./multi_ddynamic_array.sv,25)
ncsim: *W,RNDOCS: These variables contribute to the set of conflicting constraints:

rand variables:
frame_height [./multi_ddynamic_array.sv, 11]

I'm using the below NCSIM Version;

   /tools/icad/cadence_lnx/ius/141.014/tools/bin/irun

Please help in this regard whether I've missed something on constraints. However the above code is working fine with the other tools.

Thanks,

Regards,

Mahesh.

Hi,

   Does anyone tell me that the above issue will get resolved by using the latest IUS  version 15.20?

Thanks,

Regards,