From: Bill Dally [billd@csl.stanford.edu]
Sent: Wednesday, October 10, 2001 9:40 PM
To: Ian Buck
Cc: lance@leland.Stanford.EDU; ujk@leland.Stanford.EDU;
Billmark@lambert.stanford.edu; horowitz@chroma.stanford.edu;
hanrahan@graphics.stanford.edu
Subject: Brook - retained state

Ian,

Nice job on the Brook language definition so far.  I like the idea of 
moving the template declaration to the argument list.

A major difference between Brook and StreamC or my "generalized streams" 
proposal is the lack of retained state in kernels between stream 
elements.  Since you have no explicit in ">>" operator the kernel starts 
"fresh" with each input element.

With this approach, how do you handle kernels that need to communicate 
retained values between stream elements?  A simple example would be a 
kernel that sums a list of numbers.  More complex examples include things 
like sort, merge, and the composite kernel in the Imagine renderer.

----Bill
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Bill Dally                billd@csl.stanford.edu             (650)725-8945
Professor of Electrical Engineering and Computer Science  FAX(650)725-6949
Computer Systems Laboratory, Stanford University
Gates Room 301
Stanford, CA  94305                         http://csl.stanford.edu/~billd
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