How to use solve before constraint for array elements

SystemVerilog
1

Hi,

I want to achieve to have high priority to solving mode first in the below sequence. (or picking solution space where mode is equally 0 and 1)
How do i say solve mode before elements size or each elements[i] ?
I understand in the case of simple variables i can say solve mode before var;

rand bit mode;
rand bit elements[];

constraint elements_c{
elements.size() == 1024;
foreach(elements[i])
if (mode == 1) 
  elements[i] == 128;
else
 elements[i] == 256;
}

thanks in advance

for the help!

2

In reply to theketi:
There is no need for the poorly named
solve-before constraint in this example. There are only two possible solutions, and they have equal probability of being chosen.