[PD] freeverb~ problem

[Ivica Bukvic]

Do denormal optimizations also handle NaNs?

-- 
Ivica Ico Bukvic, D.M.A.
Associate Professor
Computer Music
ICAT Senior Fellow
Director -- DISIS, L2Ork
Virginia Tech
School of Performing Arts – 0141
Blacksburg, VA 24061
(540) 231-6139
ico at vt.edu
www.performingarts.vt.edu
disis.icat.vt.edu
l2ork.icat.vt.edu
ico.bukvic.net
On Feb 8, 2016 1:59 PM, "Kjetil Matheussen" <k.s.matheussen at gmail.com>
wrote:

> Carl Hetherington has a good write up on denormals:
> http://carlh.net/plugins/denormals.php
>
> This is the most interesting point:
>
>    "The P3 always has problems with denormals no matter what GCC flags or
> CPU modes are used.".
>
> So unless you want your program to function on a P3, you can safely compile
> your denormal-creating program with sse math and turn on DAZ and FTZ.
> You won't get any problems with denormals then.
>
>
>
>
>
>
>
> On Mon, Feb 8, 2016 at 4:13 PM, Ivica Ico Bukvic <ico at vt.edu> wrote:
>
>> I thought this, too. I seem to (mis)remember somewhere that -O2
>> optimization at compile-time would help with this, which is what pd-l2ork's
>> freeverb~ uses and still exhibits previously reported behavior. That said,
>> I wonder if denormals would also solve potential NaNs. At any rate, I've
>> updated freeverb~ to explicitly use denormal function's return value in
>> pd-l2ork and will run some tests and let you know. If you'd like to test it
>> out, download the latest deb dated 20160208 (64bit build only for the time
>> being).
>>
>> Best,
>>
>> Ico
>>
>>
>> On 2/8/2016 4:44 AM, Kjetil Matheussen wrote:
>>
>> Regarding denormals, if that's the problem, shouldn't it be good enough
>> to compile with -fpmath=sse -msse2 and run the following code one time in
>> the dsp thread?
>>
>> #ifdef __SSE__
>>     #ifdef __SSE2__
>>         #define AVOIDDENORMALS _mm_setcsr(_mm_getcsr() | 0x8040)
>>     #else
>>         #define AVOIDDENORMALS _mm_setcsr(_mm_getcsr() | 0x8000)
>>     #endif
>> #else
>> #   error "must compile with -fmpath=sse"
>> #endif
>>
>>
>>
>>
>> On Mon, Feb 8, 2016 at 10:28 AM, Kjetil Matheussen <
>> k.s.matheussen at gmail.com> wrote:
>>
>>> You could use the faust version of freeverb and compile it for pd. It's
>>> probably less likely to have bugs.
>>> For instance by pasting
>>> http://sourceforge.net/p/faudiostream/code/ci/master/tree/examples/freeverb.dsp?format=raw
>>> into http://faust.grame.fr/onlinecompiler/
>>>
>>>
>>> On Sun, Feb 7, 2016 at 4:08 AM, Ivica Bukvic < <ico at vt.edu>ico at vt.edu>
>>> wrote:
>>>
>>>> Thank you, Katja. Is there a newer version than this out there?
>>>>
>>>> Best,
>>>>
>>>> --
>>>> Ivica Ico Bukvic, D.M.A.
>>>> Associate Professor
>>>> Computer Music
>>>> ICAT Senior Fellow
>>>> Director -- DISIS, L2Ork
>>>> Virginia Tech
>>>> School of Performing Arts – 0141
>>>> Blacksburg, VA 24061
>>>> (540) 231-6139 <%28540%29%20231-6139>
>>>> ico at vt.edu
>>>> www.performingarts.vt.edu
>>>> disis.icat.vt.edu
>>>> l2ork.icat.vt.edu
>>>> ico.bukvic.net
>>>> On Feb 6, 2016 10:25 AM, "katja" <katjavetter at gmail.com> wrote:
>>>>
>>>>> If the freeverb~ version you use looks like the one in
>>>>>
>>>>> http://sourceforge.net/p/pure-data/svn/HEAD/tree/trunk/externals/freeverb~/freeverb~.c
>>>>> ,
>>>>> there's a function 'fix_denorm_nan_float() defined starting at line
>>>>> 154. The function is called later (in line 225 and others) but the
>>>>> return value is never stored. Therefore freeverb~ doesn't flush
>>>>> denormals.
>>>>>
>>>>> On Sat, Feb 6, 2016 at 3:34 PM, Ivica Bukvic <ico at vt.edu> wrote:
>>>>> > Thank you all. Looks like I've got some troubleshooting to do and
>>>>> will
>>>>> > report what I find.
>>>>> >
>>>>> > Best,
>>>>> >
>>>>> > --
>>>>> > Ivica Ico Bukvic, D.M.A.
>>>>> > Associate Professor
>>>>> > Computer Music
>>>>> > ICAT Senior Fellow
>>>>> > Director -- DISIS, L2Ork
>>>>> > Virginia Tech
>>>>> > School of Performing Arts – 0141
>>>>> > Blacksburg, VA 24061
>>>>> > (540) 231-6139 <%28540%29%20231-6139>
>>>>> > ico at vt.edu
>>>>> > www.performingarts.vt.edu
>>>>> > disis.icat.vt.edu
>>>>> > l2ork.icat.vt.edu
>>>>> > ico.bukvic.net
>>>>> >
>>>>> > On Feb 6, 2016 9:20 AM, "IOhannes m zmölnig" <zmoelnig at iem.at>
>>>>> wrote:
>>>>> >>
>>>>> >> On 02/06/2016 10:29 AM, katja wrote:
>>>>> >> > Possibly an inf or nan recirculating in the delay lines? It seems
>>>>> that
>>>>> >> > freeverb~ calls function fix_denorm_nan_float(float v) but
>>>>> doesn't use
>>>>> >> > the return value.
>>>>> >>
>>>>> >> you *might* be able to confirm this by sending the output for
>>>>> >> [freeverb~] to [print~] (the silent samples would be NaN or Inf
>>>>> rather
>>>>> >> than 0 (or some other constant value))
>>>>> >>
>>>>> >> gamds
>>>>> >> IOhannes
>>>>> >>
>>>>> >>
>>>>> >>
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>>>>>
>>>>
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>>
>>
>
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