13 Dec
2002
13 Dec
'02
6:24 a.m.
On Fri, Dec 13, 2002 at 02:50:52AM +0000, Simon Jenkins wrote:
Its just programmer lazyness, the modules are resolved in an order
determined by a hashtable they get stored in.
I went as far
as defining a biquad filter in the graph format
(http://plugin.org.uk/blockless/blockless/modules/biquad.g), but it
dosen't quite work because the execution order is more or less random.
I haven't looked closely yet but do you mean that the atoms are being
executed in some compiler-determined order that doesn't reflect the flow
of data through the graph? Someone suggested here that single sample latencies,
eg in feedback loops,
shouldn't cause noticeable problems. (There's got to be one somewhere
in a feedback loop anyway). The combined effect of whole load of atoms
executing in the wrong order might be a different matter though.
Yes, especially in a biquad.
value that hasn't been evaluated yet. (OTOH the
Modular is a synth not
an FPGA and I was well across the line which divides use from abuse
before I even noticed that I wasn't in control of the evaluation order).
You can control it, its goverened by the order you place the modules in
the patch. I managed to build an AD converter that way, but it was damn
hard work.
The optimisations I'm really hoping to see are for
the compiler to strip out
dead code when an output isn't connected, and to propogate a constant 0
through the graph when an input isn't connected.
Well that happens, the constant 0.0 gets propagated, because I manually
set it in the source :)
Thinking again about what the Nord Modular does: You
can make and break
connections between existing modules as much as you like with neither a
glitch nor a change in (what it claims to be its) CPU usage. As soon as you
add a new module, though, all the existing modules reset themselves and
everything "starts again" with the new module, suggesting that the existing
modules have all lost their contexts. This is *really* annoying if
you're trying
to develop a patch or sequence that evolves very slowly.
Yes, It might be possible to replicate this by use of exteme binary
mangling, but its not somewhere I want to go.
I just did this to see what would happen, if someone were going to take a
more serious stab at it they would have to take account of these issues.
- Steve