janick@bcrkd13.bnr.ca (Janick Bergeron) (02/26/91)
In article <1991Feb7.152251.29436@src.honeywell.com>, carpent@SRC.Honeywell.COM (Todd Carpenter) writes: > > RANDOM_pack.VHDL > -- This has some interesting problems. Namely, saving a seed. > -- You can do that with a global signal in a package, but it gets ugly > -- when you want to have multiple threads for uncorrelated > -- sequences. Anyone have some good ideas for a solution? > -- > -- Another route is to have the calling routine track the seed value, > -- as is the case in ZyCad's "distributions.vhd" random number package. > -- > -- Obvious functions: > -- uniform, normal, exponential. Look in the proceedings of the 1989 Canadian Conference on VLSI, pp 91-98 "Some Elements for High-Level Modelling in VHDL" by E. Cerny, M. Aboulhamid and S. Curry. It describes (amongst other things) a mechanism for random number generation and mutual exclusion. All three authors read this newsgroup so you might reach them directly... -- Janick Bergeron Bell-Northern Research, Ltd Ph.: (613) 763-5457 VHDL Tools P.O. Box 3511, Station C Fax: (613) 763-7241 Ottawa, Ontario, Canada, K1Y 4H7 Flame: 1-800-DEV-NULL janick@bnr.ca library disclaimer; use disclaimer.all;
drc@coelho (David R. Coelho) (03/01/91)
>In article <1991Feb7.152251.29436@src.honeywell.com>, >carpent@SRC.Honeywell.COM (Todd Carpenter) writes: >> >> RANDOM_pack.VHDL >> -- This has some interesting problems. Namely, saving a seed. An alternative approach I have taken to generating random numbers in VHDL is to create a simple VHDL function which reads random numbers as needed from an ascii text file using VHDL text I/O. I then wrote a simple C program which creates the ascii text file. This keeps the VHDL package tight and simple, and offers much greater flexibility in generating the random data.