[PD] freeverb~ problem

[Kjetil Matheussen]

If you mean turning on DAZ and FTZ, they shouldn't. But there should have
been a CPU flag to turn off NaNs too (i.e. create zero's instead).
Maybe there is such a flag though, I don't know.



On Mon, Feb 8, 2016 at 8:13 PM, Ivica Bukvic <ico at vt.edu> wrote:

> 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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