System Verilog rand and randc

[sam33r]

Hi,

Rand generates same iteration of randomized values again and again.
randc randomly iterates over all the values in the range and no value is repeated within an iteration.

Now can we generate the functionality of randc using only rand keyword. ?

 

[qieda]

Hi,

maybe you can do something like this.

Make a list of as many elements as the size of the range in randc
e.g. randc has a range of 0..7 you need 8 elements

each element has an index. This index is going from 0 ... 7
each element has a weight. This can be a real number between 0.0 ... 1.0

now fill your list. For the idx use your range. For the weight you can use the rand function
e.g. you will get
E[0].idx = 0; E[0].weight = 0.453;
E[1].idx = 1; E[1].weight = 0.150;
E[2].idx = 2; E[2].weight = 0.934;
E[3].idx = 3; E[3].weight = 0.443;
E[4].idx = 4; E[4].weight = 0.109;
E[5].idx = 5; E[5].weight = 0.034;
E[6].idx = 6; E[6].weight = 0.657;
E[7].idx = 7; E[7].weight = 0.234;

now you can sort your list by the the weight
in may example you will get
E[0].idx = 5; E[0].weight = 0.034;
E[1].idx = 4; E[1].weight = 0.109;
E[2].idx = 1; E[2].weight = 0.150;
E[3].idx = 7; E[3].weight = 0.234;
E[4].idx = 3; E[4].weight = 0.443;
E[5].idx = 0; E[5].weight = 0.453;
E[6].idx = 6; E[6].weight = 0.657;
E[7].idx = 2; E[7].weight = 0.934;

If you now use the idx of your sorted list you have a randc function
In may example you get 5,4,1,7,3,0,6,2


best regards