who can interpret use of soft constraint ?

[wszhong631]

Hi,I have  such a question

 

https://verificationacademy.com/forums/uvm/how-use-soft-constraint

 

who can help me ?

 

 

thanks

 

/wszhong

[apfitch]

Your soft constraint only covers the case when my_pkt is ether_pkt, so perhaps my_pkt is *not* ether_pkt,

 

Suppose there are four packet types, and data_len is 16 bits. Then you're randomizing 18 bits, that's 262144 values. But your constraint is only satisfied for 512 of those values, so there's only a 1 in (262144/512) = 1 in 512 chance of generating the value you seem to want.

 

regards

 

Alan

[tudor.timi]

I don't really get what your requirements are here. Do you want to have packets with a data length bigger than 512 or not? If 512 is a global global limit, then just don't make the constraint soft.

[uwes]

hi,

 

asking for help but raise the question in some other forum isnt helpful.

 

/uwe