Hello! I am pretty new to Pd and have some background in modular synthesis, less so in programming, so I apologize if this specific question has a simple answer, but I have really been banging my head against a wall with this.

Essentially I have an external device, connected to my computer via USB, that is sending voltage input data about 10 times per second. I've confirmed that it works as intended, and I can even get Pd to print these values, but I'm having a lot of trouble using these values. I think I have a blind spot somewhere around the scale or something...

The full setup:

• External device: an Adafruit Feather M4 Express, running CircuitPython code. This device sends a signal that varies between 0-3.3V.

• In Pd: [comport /dev/ttyACM0 115200] is bringing in the data from that device.'

• If I print directly from the [comport], it's printing numbers ranging from 10-60. Still not sure why that's different from the 0-3.3V I see when I print in the python code editor.

• I am using the Automatonism library of modules. I have a simple patch of a BASIC-OSC, connected to a LP Filter, connected to VCA, connected to Maestro4 (Mixer) connected to [dac~].

• The goal is for the output from this external device to control the Frequency Modulation on the BASIC-OSC. So far it has no effect.

• I've tried: connecting the [comport] output directly to FM, routing it through S&H first, using the simple math objects to divide the output from [comport] by 6 and subtract 5 (in an effort to get the numbers to a range of -10 to 10), and a longer sequence of objects suggested by GitHub Copilot involving [route], [scale], [pack], [line], and some more math. None of these produce a discernible effect.

• Along each of these troubleshooting attempts, I connect the output to OSCILLOSCOPE (or [print] if it's a data output) to check what's going on. The oscilloscope consistently does not show any fluctuation, but [print] continues to print a series of variable values.

I really appreciate any suggestions! Like I said I've been struggling to get this working for a while and I am not sure what I'm missing.

If it helps to upload screenshots or the patch, I can do that too.

Thanks!!!

@jamcultur said:

If the code on Windows was the same as the code on Mac, they would work the same.

One source of confusion here is the difference between source and object code.

Most of the time, humans never look at the object code produced by a compiler. We only look at the source code. So, when porres says there's no difference in the code between platforms, this is talking about source code.

The source code gets compiled into object code. In Mac vs Windows, the compilers are different, and the CPUs (architectures and instruction sets) are different. If the Mac is using an M-series CPU, then it's impossible for the object code to be the same as Windows (Intel or AMD chip), because the instruction sets are completely different. (That's also not considering the differences in OS function calls, which of course will not be the same between different OSes.) So in fact, "the code" isn't the same -- but this isn't porres's fault, and there's no way for the code not to be different.

Ideally, the same source code compiled for different chips should produce equivalent results. Programmers usually take this as a safe assumption. But there are edge cases where it might not work out that way (we just saw one of those over in SC-land, related to floating-point rounding). These cases can be extremely difficult to debug, and at the end of the day, one is at the mercy of the CPU and the compiler's behavior.

In such cases, it isn't helpful to accuse a developer of writing different code for Windows (this is implausible for DSP code in any case, which is mostly math operations that are well abstracted -- you don't need #ifdefs for std::xxx() math functions) or of "not caring" enough.

We want to assume that the compiler and CPU are transparent with respect to the source code's meaning. When that isn't the case, it's necessary to inspect every operation. It's painful, and if porres doesn't have access to a machine where the problem occurs, it can be very slow (test builds, relying on other people to run the specific tests). A little patience goes a long way.

hjh

Interesting that both responses assumed that atux wants to send pitch bend messages out, but "modulate the pitch in real time by moving a slider" says nothing about MIDI being the target.

The question might just as easily be, "How to map a slider onto a frequency ratio, to multiply with the note's main frequency?"

Normalize the slider value. Because pitch bend normally goes both up and down, I normalize to -1 .. +1.

line~ for smoothing. (Also, I'm stealing the mouse-release logic from porres, good tip!)

Pitch bend range is given in semitones. We need a fraction of an octave = pbrange / 12.

Scale the normalized pb value onto the fraction of the octave = [*~].

The ratio for one octave = 2. So, the ratio for the fraction of the octave = 2 ^ fraction.

Now you have a ratio that you can multiply by any frequency, and get pb.

(More generally, almost any kind of exponential modulation i.e. frequency can be expressed as baselineValue * (modRatio ** modulator). Pitch bend is a specific case of this, where modRatio = 2 and the modulator is scaled to the range +-pbrange / 12. Linear modulation just demotes the math ops: baselineValue + (modFactor * modulator). With these 2 formulas you can handle a large majority of modulation scenarios.)

hjh

@porres said:

I didn;t know about "LFDNoise3", is it a new one?

It's been there for years, I'd guess at least 10 years though I didn't check the commit history to confirm that.

Wow, I can't believe they have so many
I see this one is dynamic....

(Deleted snarky and irrelevant comment about the quality of the documentation, which still is better than Max/MSP's help in many respects. But there I go, being snarky and irrelevant.)

The original LFNoise UGens behave like envelopes, where the time to the next control point gets sampled-and-held. So if the frequency happens to be 0.01, the next control point will happen 100 seconds later, no matter how the frequency modulates.

Wow, that's bad

The existence of LFDNoise UGens tells you that SC developers agree with you, and solved the problem (a long time ago). So there's really not much point to taking potshots at this particular target.

and for someone not that much into math, this is not enough, can anyone help? What kind of interpolation is spline? I don't wanna look into their source code

You're into math enough to maintain a DSP-and-other-stuff library for Pd anyway a little dive into the source code shows that SC's plugin_interface headers define a function cubicinterp() that uses the same formula mentioned in the other thread, that's used in tabread4c~.

hjh

Hello, this is my first post on the forum.

I'm trying to create a high pass filter with Q using Biquad~.

As I don't have enough mathematical knowledge about filters and coefficients, I asked Chat GPT to help me understand the math, and I think I almost got it now.

The problem is that I'm executing everything it said me to, and I think the equations are correct, but it is not working properly, I get a kind of filter, but for sure it is not a high pass, and the Q always starts around 2000 Hz and I don't know why.

Can anybody please help me to understand what is going wrong?
I have some experience with Pd, but not with math or DSP.biquad_test_filter.pd

Ok, the cat is out of the bag --> https://github.com/porres/pd-else/releases/tag/1.0-rc13 I'm officialy announcing the update and uploaded binaries to deken for mac (intel/arm), Win and Linux. It all looks ok but tell me if you see something funny please. There's also a raspberry pi binary but not working 100%yet and we'll still look into that. Hopefully someone could help me/us with it. I might make another upload just for the pi later on if/when we figure it out. Find release notes and changelog below.

RELEASE NOTES:

Please support me on Patreon https://www.patreon.com/porres I'll now try to add special content for subscribers. You can follow me on instagram as well if you like... I'm always posting Pd development stuff over there https://www.instagram.com/alexandre.torres.porres/

It's been a little bit over 7 months since the last update and I almost broke the record for taking too long to release an update (which had happened in my previous update). So yeah, there's just too much to talk about! I guess the delays in releasing updates is because it's been a little tricky and hard to sync the release cycles of ELSE with PlugData, which includes ELSE in its download.

Plugdata 0.9.2 should come out soon with ELSE RC13 and it's supposedly the last update before 1.0.0, so I've heard. And the plans was to get to that still in 2025! This means ELSE could be at its last "Release Candidate" phase as I'm aiming to sync the final release with PlugData. Until then, I'll still make breaking changes and I can't wait until I can't do that anymore as I really feel bad. On the other hand, it's kind of inevitable when I'm always adding new stuff and redesigning and reconfiguring objects to include more functionalities. And I always got a lot of new stuff! So I'm thinking that I will eventually try some mechanism like Pd's compatibility flag or something. I'll try to come up with something like that in the next update.

This update has 22 new objects for a total of 573 and 26 new examples in my tutorial for a total of 554 examples. Let's dive into the highlights (see full changelog below after the release notes).

• Multichannel Support: Last release had 92 MC aware objects, now it's 139! Over a 50% increase that include old and new objects (all the new ones have been coming with MC support). Virtually all oscillators and envelope generators now have MC support, plus some other random ones. Let me highlight the new [lace~]/[delace~] objects that are 'MC' tools that perform interleave/deinterleave in Multichannel connections. My bare minimum number of objects "to start with" would be at least a bit over half the number of signal objects. That was my target for 1.0! ELSE right now has 319 signal objects, so that'd be at least 160. I will definitely pass this milestone in the next update. I guess a good number of MC objects would be around 75% of the signal objects. I will aim for that as soon as I can. Some objects simply can't be MC at all, so 100% will never be the case, but maybe an ideal 90% eventually? We'll see... I am just proud and happy that ELSE is taking such a big jump on MC awareness in less than a couple years.

• Envelope generators ([adsr~]/[asr~]/[envgen~]/[function~]) now have more curve options. For [adsr~]/[asr~] the default is now a new log curve that you can set the curve parameter (and was 'stolen' from SuperCollider). A new [smooth~] family of objects perform the same kind of curved smoothening for alternating inputs - [envgen~] and [function~] also have that but also '1-pole' filtering, 'sine' and 'hann' curves. You can now trigger [adsr~] and [asr~] with impulses.

• The [play.file~] object now supports even more file formats besides MP3 and stuff. Hey, you can even stream the supported formats from weblinks! The [sfload] object (which loads files into arrays) also gained support for more formats and can download from weblinks as well! It also has a new threaded mode, so loading big files won't choke Pd. It now also outputs the file information, which is a way to tell you when loading finished in threaded mode. The [sample~], [player~], [gran.player~] and [pvoc.player~] objects are now also based on [sfload], so they support all these file formats!!! Now [sample~] and [tabplayer~] are integrated in a way that [tabplayer~] is always aware of the sample rate of the file loaded in [sample~] (so it reads in the "correct speed"). A new [sfinfo] object is able to extract looping regions and instrument metadata information from AIFF files (which is something I wanted for ages) - it should do more stuff in the future.

• [knob] has become the ultimate featured bloated creep GUI I always feared and avoided. MAX is envy! but I'm happy with this structure and I want to replicate in other GUIs in the future (yeah, I got plans to offer alternatives to all iemguis). I wanna highlight a new 'param' symbol I added that allows you to remotely set a particular method in an object, so you don't to connect to a "method $1" message and you can even do this wirelessly with a send symbol. [knob] now also acts like a number box, where you can type in the value, which may also be displayed in different ways or the value can be sent elsewhere via another send symbol so you can temper with it using [makefilename] or [else/format]. I've been using this for the MERDA modules and it's really cool.

• We finally have a [popmenu] GUI object! This was in my to do list forever and was crucial to improve the MERDA modules to set waveforms, instruments and whatnot.

• Let's about MERDA, the "Modular Euroracks Dancing Along" subset of abstractions in ELSE. It was first released in the last update and it's been driving lots of the development in ELSE as you can see. I now added a MIDI Learn feature for all knobs that feels great and quite handy! There are many fixes and improvements in general and some new modules. I wanna highlight the new [sfont.m~] module, which loads "sound font" banks and you can just click on a [popmenu] to choose the instrument you want. The default bank has numerous (hundreds) options and also comes with PlugData. The sequencer module [seq8.m~] was rather worthless but it's now a whole new cool thingie. It allows you to set pitches with symbols and even has quarter tone resolution. I added a right outlet to send impulses to trigger envelopes and stuff (there's still more stuff of course, see full changelog below).

• There are newly designed/renamed/recreated [resonbank~]/[resonbank2~] objects that are well suited for Modal Synthesis.

• What actually drives my development is my Live Electronics tutorial, which got a fair upgrade with a new chapter on Modal Synthesis amongst other things, such as new subtractive synthesis examples and a revision of envelope generators with examples on AHDSR and DAHDSR - by the way, there are new gaterelease~/gatedelay~ objects for handling envelopes (and other processes).

• I have to thank some people. Tim added 'zoom' to the [pic] object, as well as an image offset. Tim also implemented a new and better technique for bandlimited oscillators. Ben Wesh gave me a new [scope3d~] GUI object, pretty cool, that plots an oscilloscope in 3 dimensions, which is coded in LUA - and ELSE has been carrying a modified version of [pdlua] because it now depends on it for a couple of GUIs. Tim and Ben made many improvements to [pdlua] (as well as Albert Graef, of course).

• For more new objects, let me also tell you about the simple and cool [float2imp~], that is based on [vline~] and can convert floats to impulses with sample accuracy (don't know why I didn't think of that earlier). A new [tanh~] object has Multichannel support. A bit earlier I made an update to Cyclone that actually "borrows" and includes this one from ELSE instead of its original one (which does not have Multichannel support). PlugData users will load the one from ELSE. This is another tiny step that sort of integrates ELSE and Cyclone, specially for PlugData users.

happy patching.

CHANGELOG:

LIBRARY:

Breaking changes:

• [adsr~]/[asr~]: now a gate off before reaching the sustain point does not start the release right away (this allows you to trigger it with impulses). There's a new mode just for immediate release. There's a new exponential setting for curve factors, the old 'log' mode is renamed to 'lag' as it's the same as used in the [lag~] object. For [adsr~], a bang now is not "retrigger", but an impulse at control rate, there's a new 'retrigger' message for control rate retriggering (and now it only retriggers if the gate is on). For [asr~] a bang now also works like an impulse.
• [sample~]: no more 'load' message, args to 'open' message changed, size is now only in 'ms'.
• [format]: outputs are now always symbols, before you could get float outputs. Also, we just have a simplified symbol output, no more lists or anythings. Hopefully I'll be able to get the 'list' output back, but it involved some bugs that I couldn't fix so I just removed it. You cannot use bangs and lists in secondary inlets no more (this is cylone/max crappy paradigm we don't want here). Bang method was actually removed as well.
• [pack2]: no more support for anythings, also no more support for lists in secondary inlets and output has a list selector (I wanna make this more Pd like and not a silly clone from MAX's [pak], cause fuck MAX).
• [merge]/[unmerge]/[group]: no more '-trim' flag (again, respecting pd's usual list paradigm), in [merge] now there's no more 'hot' argument and a bang now represents an empty list and inlets initialized with empty lists
• [mono]: 1st argument is now 'glide' in ms.
• [sfont~] now uses 'mma' for bank selection (this alters how CC messages set the bank number).
• [player~]/[play.file~]: 'open' message does not play files right away anymore.
• [tabplayer~]/[player~]: play message without args now play at the default settings (whole file at regular speed).
• [envgen~]: removed the 'maxsustain' parameter, use the new [gaterelease~] or [gaterelease] objects instead. Removed the rightmost inlet just to set envelopes, now a list input only sets the envelope and doesn't trigger it. The 'set' message is then removed.
• [envgen~]/[function~]: simplified and got rid of '-exp' flag and message, also deleted 'expl' and 'expi' messages. A new 'curve' and cimpler message sets exponential factors for all or individual segments, and includes more curve formats.
• [knob]: 'esc' key now deactivates the object. The 'ticks' message is renamed to 'steps' and there is a new 'ticks' message that toggles showing ticks on and off. The 'start' message has been renamed to 'arcstart'. The 'outline' message has been renamed to 'square' for better clarity. Design changed a bit to make it like it is in PlugData (they won), so we now fill the whole background color when in 'square mode' and the knob circle has an 85% proportion in this case inside the full 100% square size (so it grows bigger when not in 'square' mode). Now, by default, the GUI is in a new 'loadbang' mode (I don't think this will influence old patches). I'm afraid some old patches might behave really weird since I added a lot of new stuff. I changed the 'load' message behaviour to not update the object (this can arguably be considered a bug fix).
• [wavetable~], [bl.wavetable~] and [wt2d~]: 'set' message now sets frequencies because of the MC support in [wt~] and [wt2d~], while there's a new 'table' method to set the table name.
• [gbman~]/[cusp~] list method is now for MC, old list method is now renamed back to an old 'coeffs' method.
• [f2s~]/[float2sig~] default value is now 10 ms.
• [op] now behaves like [*~] where the smaller list wraps til reaching the size of the longer one.
• [list.seq] does not loop anymore by default.
• [impseq~] list input removed, use the new [float2imp~] object to convert floats to impulses.
• [resonant~] now has 'q' as the default.
• [resonant2~] has been removed.
• [decay2~] has also been removed ([asr~] much better).
• [vcf2~] has been renamed to [resonator2~].
• [resonbank~]/[resonbank2~] have basically been deleted and replaced by new objects with the same name... [resonator~] is based on a new [resonator~] object which is similar to [resonant~] and [resonbank2~] is now based on [resonator2~] (old [vcf2~] instead of [resonant2~] that got deleted). These are well suited objects for Modal Synthesis.
• [oscbank~] now uses a 'partial' list and not a frequency list. The freq input now defaults to '1' and this makes [oscbank2~] completely obsolete.
• [oscbank2~] has been deleted since it became completely obsolete.
• [sfload] load message changed the behaviour a bit.

Enhancements/fixes/other changes:

• [adsr~]: We have now a new mode for immediate release (see breaking changes above, I'm not repeating it). Fixed ADSR signal inputs (it was simply not really working, specially for linear). Fixed status output for MC signals. There's a new curve parameter that allows you to set the curvature.
• [asr~] I actually just made the new [adsr~] code into a new [asr~] code as a simplified version (as it was before)... so it's got the same impromevents/fixes.
• [play.file~]: added support for more file formats and even weblinks for online streaming!
• [sfload]: added an outlet to output information, added threaded mode, added support for more file formats and even weblinks for downloading.
• [sample~], [player~], [gran.player~] and [pvoc.player~] are now also based on [sfload], so they support more file formats!
• [sample~]: improved extension management with [file splitext].
• [sample~] and [tabplayer~] now are automatically integrated in a way that [tabplayer~] is always aware of the sample rate of the file loaded in [sample~], so it automatically adjusts the reading speed if it is different than the one Pd is running with.
• [numbox~]'s number display is not preceded by "~" anymore (that was just kinda stupid to have).
• [format]: fixed issues where empty symbols and symbols with escaped spaces didn't work. Added support '%a' and '%A' type. Added support for an escaped 'space' flag. Improved and added support for length modifiers. Improved syntax check which prevents a crash. Improved documentation.
• [knob]: added new 'param', 'var', 'savestate', 'read only', 'loadbang', "active", "reset" and 'ticks' methods. Added the possibility to type in number values and also modes on how to display these number values, plus new send symbols for 'activity', 'typing', 'tab' and 'enter'. New design more like plugdata. Changed some shortcuts to make it simpler. If you have the yet unreleased Pd 0.56-0 you can also use 'double clicking' in the same way that works in PlugData. Properties were also significantly improved (I'm finally starting to learn how to deal with this tcl/tk thingie). Yup, a lot of shit here...
• [autofade2~]/[autofade2.mc~]: fixed immediate jump up for 0 ramp up.
• [synth~]: fixed polyphony bug.
• [metronome~]: fixed bug with 'set' message.
• [midi2note]: fixed range (octaves 0-8).
• [pulsecount~]: fixed reset count to not output immediately, added bang to reset counter at control rate
• [click]: fixed regression bug where it stopped working.
• [else]: new 'dir' method to output ELSE's binary directory in a new rightmost outlet. The print information also includes the directory.
• [pic]: added zoom capability finally (thanks to tim schoen) and added offset message (also thanks to tim).
• [store]: added 'sort' functionality.
• [scales]: fixed octave number argument. Added functionality to allow octave number as part of the note symbol.
• [mono]: added 'glide' parameter, as in [mono~].
• [pluck~]: fixed list input.
• [rescale]/[rescale~]: added a "reverse log" mode.
• [limit]: added a new second ignore mode.
• [graph~]: added an external source input for plotting the graph and a 'clear' message.
• [canvas.setname]: added a new argument for "abstraction mode" and methods to set name, depth (and mode).
• [midi.learn]: added a new argument for "abstraction mode", fixed 'dirty' message sent to parent.
• [brickwall~]: fixed initialization.
• [list.seq]: added a loop mode and a 2nd outlet to send a bang when the sequence is done.
• [delete]: fixed index for positive numbers.
• [dust~]: added 'list', 'set' and '-mc' flag for managing the already existing Multichannel capabilities.
• Thanks to Tim we have many fixes and a whole new technique for band limited oscillators. Now [bl.saw~], [bl.saw2~], [bl.vsaw~], [bl.square~], [bl.tri~], [bl.imp~] and [bl.imp2~] have been redesigned to implement elliptic blep, which should provide better anti-aliasing.
• [parabolic~] now uses and internal wavetable for more efficiency.
• [resonant~]: added 'bw' resonance mode.
• [lowpass~]/[highpass~]: added 't60' resonance mode.
• [quantizer~]/[quantizer]: added a new mode, which combines floor (for negative) and ceil (for positive) values.
• [crusher~]: now uses the new [quantizer~] mode from above (arguably a breaking change).
• [envgen~]: fixed a bug (actually a misconception) where ramps started one sample earlier. Fixed 0-length lines. Added a possibility to set time in samples instead of ms. Maximum number of lines is now 1024. Added loop mode. Added many curve options (sin/hann/log curve/lag).
• [function~]: Added many curve options (sin/hann/log curve/lag).
• [The out~] family of abstractions now use [bitnormal~] so you won't blow your speakers beyond repair in edge cases.
• [trig.delay~]/[trig.delay2~]: fixed bug where impulse values different than '1' didn't work.
• Added MC support to: [trig.delay~], [trig.delay2~], [gatehold~], [vca.m~], [gain2~], [decay~], [asr~], [envgen~], [function~], [bl.osc~], [bl.saw~], [bl.saw2~], [bl.vsaw~], [bl.square~], [bl.tri~], [bl.imp~], [bl.imp2~], [imp2~], [tri~], [saw~], [saw2~], [vsaw~], [square~], [pulse~], [parabolic~], [gaussian~], [wavetable~], [wt2d~], [randpulse~], [randpulse2~], [stepnoise~], [rampnoise~] [pink~], [gbamn~], [cusp~], [gray~] and [white~].
• Also added MIDI input and soft sync to [imp2~], [tri~], [saw~], [saw2~], [vsaw~], [square~], [pulse~], [gaussian~] and [parabolic~].
• [wavetable~] and [wt2d~] gained args to set xfading.
• Updated pdlua to 0.12.23.
• M.E.R.D.A: Added MIDI-LEARN for all modules (this is only for the knobs). Replaced some number boxes that were attached to knobs by an internal number display mechanism (new feature from knob). Improved interface of [gendyn.m~]. Preset/symbol name fixes to [flanger.m~]. Now we have automatic MIDI mode detection for [plaits.m~] and [pluck.m~] when no signals are connected (still trying to get plaits right, huh? Yup! And bow MIDI input with monophony and trigger mode has been fixed in [plaits.m~]). Added MC support to [vca.m~]. Increased range of [drive.m~] down to 0.1. Changed some objects to include the new [popmenu] GUI. [vco.m~] now uses the new MC functionalities of oscillators and doesn't need to load abstractions into [clone], I hope it makes this more efficient and clean. The [seq8.m~] module was worthless and got a decent upgrade, it's practically a new module. Added new modules (see below). Note that MERDA is still at alpha development phase, much experimental. Expect changes as it evolves.
• 22 new objects: [float2imp~], [lace], [delace], [lace~], [delace~], [gatehold], [gatedelay],[gatedelay~], [gaterelease~], [gaterelease], [popmenu], [scope3d~], [tanh~], [resonator~], [sfinfo], [smooth], [smooth2], [smooth~], [smooth2~], [dbgain~], [level~] plus [crusher.m~], [sfont.m~] and [level.m~] MERDA Modules.

Objects count: total of 573 (319 signal objects [139 of which are MC aware] and 254 control objects)!

• 323 coded objects (210 signal objects / 113 control objects)
• 227 abstractions objects (87 signal objects / 140 control objects)
• 23 MERDA modular abstractions (22 audio / 1 control)

TUTORIAL:

• New examples and revisions to add the new objects, features and breaking changes in ELSE.
• Added the MERDA modules into the examples for reference.
• Revised section on envelopes.
• New subtractive synthesis examples.
• New chapter on Modal Synthesis.
• Total number of examples is now 554! (26 new ones)

@oid said:

@inari said:

However what's not clear is how these different sample rates get into the filter blocks, which use x_sr for calculating their coefficients.

But they also use c_coef and c_x which take current sample rate into account because they are type _samplerate. From d_ugen.c:

/* ------------------------ samplerate~~ -------------------------- */

static t_class *samplerate_tilde_class;

typedef struct _samplerate
{
    t_object x_obj;
    t_float x_sr;
    t_canvas *x_canvas;
} t_samplerate;

static void samplerate_tilde_bang(t_samplerate *x)
{
    outlet_float(x->x_obj.ob_outlet, canvas_getsr(x->x_canvas));
}

static void *samplerate_tilde_new(void)
{
    t_samplerate *x = (t_samplerate *)pd_new(samplerate_tilde_class);
    outlet_new(&x->x_obj, &s_float);
    x->x_canvas = canvas_getcurrent();
    return (x);
}

static void samplerate_tilde_setup(void)
{
    samplerate_tilde_class = class_new(gensym("samplerate~"),
        (t_newmethod)samplerate_tilde_new, 0, sizeof(t_samplerate), 0, 0);
    class_addbang(samplerate_tilde_class, samplerate_tilde_bang);
}

/* -------------------- setup routine -------------------------- */

void d_ugen_setup(void)
{
    block_tilde_setup();
    samplerate_tilde_setup();
}

I think if you do the math it will work out but I could be missing something, OOP in C plus heavy pointer use plus math symbols thrown about with pointer symbols always leaves me a but unsure of what is going on if not completely lost.

The use of globals across multiple files in the PD source as well as the breaking of OOP principles by calling member functions of blocks that aren't used (looking at you osc~, vcf~ and cos~) amounts to a crime against humanity... A shame really. If you don't look at how the sausage is made, PD is a nifty little language, but the moment something breaks or needs to be extended, watch out...

@inari said:

However what's not clear is how these different sample rates get into the filter blocks, which use x_sr for calculating their coefficients.

But they also use c_coef and c_x which take current sample rate into account because they are type _samplerate. From d_ugen.c:

/* ------------------------ samplerate~~ -------------------------- */

static t_class *samplerate_tilde_class;

typedef struct _samplerate
{
    t_object x_obj;
    t_float x_sr;
    t_canvas *x_canvas;
} t_samplerate;

static void samplerate_tilde_bang(t_samplerate *x)
{
    outlet_float(x->x_obj.ob_outlet, canvas_getsr(x->x_canvas));
}

static void *samplerate_tilde_new(void)
{
    t_samplerate *x = (t_samplerate *)pd_new(samplerate_tilde_class);
    outlet_new(&x->x_obj, &s_float);
    x->x_canvas = canvas_getcurrent();
    return (x);
}

static void samplerate_tilde_setup(void)
{
    samplerate_tilde_class = class_new(gensym("samplerate~"),
        (t_newmethod)samplerate_tilde_new, 0, sizeof(t_samplerate), 0, 0);
    class_addbang(samplerate_tilde_class, samplerate_tilde_bang);
}

/* -------------------- setup routine -------------------------- */

void d_ugen_setup(void)
{
    block_tilde_setup();
    samplerate_tilde_setup();
}

I think if you do the math it will work out but I could be missing something, OOP in C plus heavy pointer use plus math symbols thrown about with pointer symbols always leaves me a but unsure of what is going on if not completely lost.

@Luizagimenez said:

I have a work assigned to translate some Graphs from UV lightning on molecules to an array in Pure Data. Im trying to find a way to get the Quadratic Equations that have complex numbers to show on a somewhat precise array or graph, so i can use these numbers for frequencies, to create a movable bar to select a pixel of the graphic.

Pd can express any math formula, but it's more cumbersome for complicated math expressions than a text-based language. [expr] helps somewhat, though. A real-number (no complex) quadratic would look like this:

If a quadratic is ax2 + bx + c, and you need complex numbers, is it that a, b and c can be complex, or only x? Your graph suggests a real-number domain, in which case complex a, b, c would be the sum of 2 quadratics, one multiplied by i. So, the above patch, but duplicated, to give you a real and an imaginary result.

If x can be complex too, then it's more involved than that.

hjh

you could make a simple abstraction that just outputs a certain number when banged:
multi-math.zip