Davide Rocchesso wrote:
>
>
> I think that the distinction between a-rate and k-rate is a serious
> semantic problem in csound and saol. This immediately appears when one
> tries to write his own digital filter without using the predefined
> blocks: the results are likely to be correct only if s-rate = k-rate.
No, what you say is incorrect; this is a difference between SAOL and
csound. The digital filter in SAOL does "the right thing" when you
define it in the obvious way. I agree that this is a semantic problem
in csound; that's why it's fixed in SAOL.
The problem that you get in return is the one I mentioned: you
can't block-process every segment of code and get the right
answer. Some SAOL code *must* be sample-by-sample processed to
get the conforming answer. (saolc does everything sample-by-sample).
So changing the language semantics as we've done in SAOL leads to
a potential efficiency hit.
> Still, I think that some efficiency might
> be gained from distinguishing k-rate from a-rate without doing block
> computation, if we just execute the operations for k-variables every a/k
> samples. This might save time for envelopes or LFOs.
This is exactly the way 'saolc' works. Also, k-rate variable are
used for message-passing between instruments, between the score and
the orchestra, and between the "host" (the systems layer) and the
SA decoding process -- you can't whip a-rate variables back and forth
for these purposes.
> I would like to see only a small set of significant primitives, thus
> avoiding the jungle of versions such as in csound. I have some ideas
> about what should be there and I would be pleased to share them if
> needed.
It is very important to note that the ONLY core primitives in
SAOL are the ones defined in the standard. When the standard finishes
in October, the process of adding core opcodes and wavetable
generators is CLOSED, and the language is fixed for all time.
If you have some idea for important primitives which aren't in
the language yet, post them right away so we can talk about them!
Best,
-- Eric
-- +-----------------+ | Eric Scheirer |A-7b5 D7b9|G-7 C7|Cb C-7b5 F7#9|Bb |B-7 E7| |eds@media.mit.edu| < http://sound.media.mit.edu/~eds > | 617 253 0112 |A A/G# F#-7 F#-/E|Eb-7b5 D7b5|Db|C7b5 B7b5|Bb| +-----------------+
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