Date: Sun Apr 15 2007 - 22:24:49 PDT
From Verification Guild: Item 58 - Topic: How does Rand Join work in SV? ( http://verificationguild.com/modules.php?name=Forums&file=viewtopic&t=17 59) Posted by: zjzzjz at 10 Apr 2007, 04:04 AM EDT Subject : How does Rand Join work in SV? Hi All, I am learning the section about random sequence generation of SV these days. The SV spec @ 12.16.5 discusses 'Interleaving productions - rand join'. It gives the following decription of the optional expression following the rand join keywords, which I can not quit understand. The example it gives seems too simple to say how RandJoin works. It only talks about the two sequences which are 'rand join', how about the more than 3 sequences are joined randomly together? And How about the length of the sequence which are joined is not same? How about the case like? T:rand join S1, S2, S3; S1: A B C S2: D E S3: F G H I Thank you very much. ///////////////////////////////////////// The optional expression following the rand join keywords must be a real number in the range 0.0 to 1.0. The value of this expression represents the degree to which the length of the sequences to be interleaved affects the probability of selecting a sequence. A sequence's length is the number of productions not yet interleaved at a given time. If the expression is 0.0, the shortest sequences are given higher priority. If the expression is 1.0, the longest sequences are given priority. For instance, using the previous example: TOP : rand join (0.0) S1 S2 ; Gives higher priority to the sequences: A B C D C D A B TOP : rand join (1.0) S1 S2 ; Gives higher priority to the sequences: A C B D A C D B C A B D C A D B If unspecified, the generator used the default value of 0.5, which does not prioritize any sequence length. At each step, the generator interleaves nonterminal symbols to depth of one. ///////////////////////////////////////// ( http://verificationguild.com/modules.php?name=Forums&file=viewtopic&p=78 87#7887) Shalom Bresticker Intel Jerusalem LAD DA +972 2 589-6852 +972 54 721-1033 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
