Hi Miller,

Meanwhile as Guenter Geiger suggested, I could simply add a noise~ multiplicated with a small value (0.000000000001) to the input of the offending patch.

About the patches involved in the problem, the rev4~ is one of them...

I've found the same problem in jMax too :-)

And what about my previous message (Consistency Check failed: signal_free 2) ?

Many thanks.

Alessandro Fogar

----- Original Message ----- From: Miller Puckette mpuckett@man104-1.UCSD.Edu To: sfogar@libero.it Cc: PD-list pd-list@iem.mhsg.ac.at Sent: Friday, June 16, 2000 9:16 PM Subject: Re: delwrite/vd question

Hi all,

There is a recurring problem in Pd whose symptom is that CPU usage sometimes shoots upward unexpectedly. The cause is usually arithmetic underflows in tilde objects. I've tried to find ways to prevent this but it looks like I haven't got it quite right yet.

For example, in a delay feedback loop, if there's input followed by a stream of zeros, eventually the recirculating values drop below 1E-38 or so. Each time a calculation does this the processor receives a hardware interrupt!

I believe the I386 offers a way to disable this interrupt but I haven't been able to find out how to do it in Linux. Does anyone on the list know about this???

My workaround has been to fix delwrite~ to bash its input to zero whenever it drops below 1E-20. Apparently this doesn't work in every case. If anyone would like to e-mail me an offending patch I'll be happy to try to figure out where the underflows are occurring and fix Pd so they will stop.

cheers Miller

Does anyone on the list know if On Tue, Jun 13, 2000 at 04:16:48PM +0200, sfogar@libero.it wrote:

...

Hi everybody,

I'm developing my new installation with pd under Linux but I notice a strange behaviour.

I'll try to explain it...

When, in patchers which use delwrite~+vd~, there is no audio flowing, the cpu utilization increases.

For example, you have a patcher which reads a sample, plays it through a chorus or a reverb, the audio goes to a dac~, when the sample is played, the cpu utilization is at a certain level, when the sample is not played, the cpu utilization increases.

Is this normal ? Am I wrong ? Is there a possible workaround ?

I'm using an RME Hammerfall 9636.

Regards

Alessandro Fogar