[PD] expr "copysign" function doesn't seem to work

Alexandre Torres Porres porres at gmail.com
Tue Jun 9 08:54:14 CEST 2015 

oops, found another issue - it won't if you try to load the name of a table
as an argument inside expr, something like [expr $2 [ $1 ]] won't load.
This seems to be related to what I've been already mentioning... workaround
would be [expr $s1 [ $1 ]] and then send table name via [symbol $2] as
illustrated by attached image.

cheers



2015-06-09 3:47 GMT-03:00 Alexandre Torres Porres <porres at gmail.com>:

> thought I'd send a patch with the last issues I brought up. Find it
> attached, it sumarizes well the issues.
>
> I thought of an easier workaround for "$0" and arrays, just send the name
> via [symbol $0-x]. I included that in my patch.
>
> I thought of another good reason to use an array instead of in a [table]
> object. You can store values in an array, save it in the patch. Somehow
> this is not possible with [table], so you always need to set it and fill it
> when you load the patch.
>
> One last thing, I guess it'd be good to make a more detailed and extensive
> help file for expr. It'd make cristal clear how to use all the functions
> with the correct syntax and there'd be no need for checking the
> documentation website. For instance, it isn't clear anywhere in the
> documentation or help file what is the syntax for "sum"/"size", for
> instance.
>
> The help file could also show possible issues and workarounds like I'm
> raising up here.
>
> cheers
>
>
>
> 2015-06-09 3:18 GMT-03:00 Alexandre Torres Porres <porres at gmail.com>:
>
>> Hi, I got more stuff !!! Not really about the functions in expr, though.
>> The thing is that expr has a hard time managing symbols and numbers in pd.
>>
>> *ISSUE 1* - Problems with "$1", "$2", etc...
>>
>> You can load arguments in expr with no problems IF it is actually being
>> loaded into an abstraction that is receiving arguments. But when it is not
>> receiving arguments you need to be careful on where it is placed, it needs
>> to be placed by itself with spaces before and after.
>>
>> For example, if you have [expr $1+1] in an abstraction that is receiving
>> one argument it's ok. But if that's not the case, it won't load the object.
>> The only way you can load the object with no argument being passed to it is
>> like [expr $1 + 1], then $1 will receive a value of "0" like it should, and
>> everything is fine.
>>
>> Another example, if you have an "if" expression, such as [expr if($1 ==
>> 1, x, y)] - there's no deal if it's not getting an argument. But if you
>> have it as [expr if( $1 == 1, x, y)] is fine!
>>
>> I can't think of any good reason why it works when arguments are passed,
>> but if fails when there are no arguments and they're getting values of "0".
>> If it works one way it also should work the other way. So it's a bug for
>> me...
>>
>> *ISSUE 2 *- Problems with $0
>>
>> expr can read tables from the patches, and also variables in the [value]
>> object. But when these elements are being used with the local variable "$0"
>> we have issues.
>>
>> Influenced by the 13.locality example in Pd, I'm used to create local
>> variables such as "$0-x". But in expr this won't load as a symbol, $0 will
>> become the patch code number "-" will define subtraction and "x" will be
>> considered the variable. I guess it'd make sense if if it worked
>> considering "$0-x" as a symbol (thus, a variable) but I understand expr is
>> actually doing what makes sense to it. I also think it may be a pain trying
>> to make this work. I'm actually fine with it if it turns out to be too
>> troublesome, but it'd be nice to mention this in the documentation or help
>> file.
>>
>> But if we need to do this in some other way, we also have a hard time
>> dealing with it. If you try "$0x", "$0.x" or "$0_x" it won't load! Now, I
>> assume this problem might be closely related to the first issue I mentioned
>> here with "$1". So it might be fixable in a similar fashion.
>>
>> Continuing, the only way it works is if you put "$0" after a symbol, such
>> as "x$0" or "x_$0". I can't think of a reason why this works and not the
>> other, so looks like a bug for me too.
>>
>> But then, is there any problem if you have to do it only like this?
>> Actually, there is! All is fine in the case of [value], it'll load [v x$0]
>> or whatever. All is also fine if you are using a table object, such as
>> [table x$0] or [table x_$0]. The problem emerges when you are using an
>> array not loaded as an object. So, if you're using a table that you need
>> for display, it's quite a headache.
>>
>> This is because "array" has issues of his own. If you have an array named
>> "x$0" it won't read in an object like [tabread x$0]! Maybe this is a
>> parallel issue that should be looked into. I guess they way Pd handles $0
>> in messages is tricky, but it is the opposite issue of expr. The array will
>> work fine with $0 before symbols, but won't work well if it's afterwards.
>> So an array named "x$0" won't work...
>>
>> Well, it does work if you set it as "$0-x" for example. But I've already
>> mentioned how it won't load in [expr]...
>>
>> So, basically, if you want to do this, you need a somewhat complicated
>> workaround. Since expr will only load something like "x_$0", you need to
>> create an array and replace $0 by the actual number of that patch. Further
>> workarounds may allow you to automatically rename that array when you load
>> the patch, but it's not easy.
>>
>> I know arrays are not making it easy, and maybe they could collaborate -
>> but it'd be just fine if expr allowed something like "$0_x" like all other
>> objects do! That'd be great.
>>
>> *ISSUE 3 *- Problems with exponential numbers
>>
>> Pd will automatically convert "0.00001" to "1e-05". This will work in
>> every object in Pd, but not expr! Because of this, we need workarounds such
>> as putting it in parenthesis, like [expr (0.00001)], or use the pow
>> function in expr, like [expr pow(10, -5)]. But since the behaviour in expr
>> is different than everything else, I consider it a bug that may be worked
>> out.
>>
>> Looking forward for the fixes. Please tell me if you think you can work
>> this all out.
>>
>> Thanks
>>
>>
>>
>> 2015-06-08 12:32 GMT-03:00 Shahrokh Yadegari <sdy at ucsd.edu>:
>>
>>> Thank Alexandre for that detailed list. It is very helpful. I will
>>> address them in the next couple of weeks, and now that Miller has suggested
>>> a path forward for committing the changes, hopefully the fixes show up in
>>> the official releases soon.
>>>
>>> As for Max/MSP versions, yes I have had plans for a while, and it is on
>>> my list to be done this summer, if something else does not take over my
>>> allocated time.
>>>
>>> cheers,
>>> Shahrokh
>>>
>>>
>>> On Sun, Jun 7, 2015 at 11:45 PM, Alexandre Torres Porres <
>>> porres at gmail.com> wrote:
>>>
>>>> Hello, great to hear from you. Yes, I got that fix, but I never
>>>> compiled it and was just hoping someday it'd show up as an update, and I'm
>>>> just worried it never came to be. Sorry to put you on the spot. I'm still
>>>> learning about the bug reports work and get dealt with in Pd, people in the
>>>> list were explaining to me today in fact. But since everyone is gathered
>>>> here, instead of me making a bug report, I'll just post everything I found
>>>> wrong or funny. I spent a great deal of time testing, here we go:
>>>>
>>>> - the help file of [expr] gives the wrong link to expr documentation,
>>>> it points to http://www.crca.ucsd.edu/~yadegari/expr.html where it
>>>> should point to the new link http://yadegari.org/expr/expr.html
>>>>
>>>> - The random function is not listed in the documentation link above.
>>>> But it's great and I always use it. It has a bug in Pd extended 0.42 where
>>>> [expr random(1000, 100001)] will eventually give negative numbers. But,
>>>> somehow, this seems to be fixed in vanilla 0.46-6.
>>>>
>>>> - the "if" function is mentioned twice in the documentation
>>>>
>>>> - The function "Sum" is not working yet.
>>>>
>>>> - In the code we see other functions for tables that are not mentioned
>>>> on the
>>>> documentation link They are: "avg", "Avg" and "Store" - but none of
>>>> which seem to be working as well!
>>>>
>>>> - there's this "copysig" issue (which is written wrong int the
>>>> documentation as "copysign") and it seems to not be working.
>>>>
>>>> - expr will consider integers as integers, so [expr 5 / 4] results in
>>>> "1". You can do something like [expr 5./ 4] for it to work, or use the
>>>> float function like this:  [expr float(5) / 4]. Now, this may not be a bug
>>>> or wrong, but if you use [expr float(1.4)] it'll return you "1" instead of
>>>> "1.4", and I guess it should be "1.4" anyway...
>>>>
>>>> - [expr imodf($f1)] and [expr ldexp($f1)] are not loading
>>>>
>>>> - [expr drem($f1)] loads with one argument, but the documentation says
>>>> it takes two arguments. Even though it loads, it doesn't seem to be
>>>> working, it sends lots of errors, such as "error: expr: FUNC_EVAL(1291):
>>>> bad right type 0 /// expr: bang: unrecognized result 0 /// error: expr:
>>>> FUNC_EVAL(1291): bad right type 3
>>>>
>>>> - One's comlpement will load like this [expr $f1 ~ $f2]. Not sure what
>>>> it's supposed to be, but it seems the second argument doesn't affect it at
>>>> all.
>>>>
>>>> - "floor" and "ceil" will load with two arguments, documentation says
>>>> it was only one! Not sure what they're supposed to be, but it doesn't seem
>>>> right cause it always returns the 1st argument in both of them.
>>>>
>>>> - "fmod", wrong number of arguments in the documentation, it takes two!
>>>>
>>>> - In the documentation, you have "
>>>> atan()
>>>> 1
>>>> inverse hyperbolic tangent"
>>>> but I belive it should be "atan*h*"
>>>>
>>>> - Code says
>>>>
>>>>  *      The following are done but not popular enough in math libss
>>>>  *      to be included yet
>>>>  *              hypoth - Euclidean distance function
>>>>  *              trunc
>>>>  *              round
>>>>  *              nearbyint -
>>>>
>>>>
>>>> So, maybe they are popular enough nowadays? Maybe they're ready to be
>>>> included?
>>>>
>>>> Well, that's what I found so far. I'm no mathematician, so I can't find
>>>> anything else I guess. I could test other functions but I wouldn't know if
>>>> they are correct.
>>>>
>>>> Anyway, sorry I can't help more getting into the code issues. I'm at a
>>>> point now that I wish I know more about programming so I can help Pd
>>>> development.
>>>>
>>>> Thanks
>>>>
>>>>
>>>>
>>>> 2015-06-08 3:08 GMT-03:00 Shahrokh Yadegari <sdy at ucsd.edu>:
>>>>
>>>>> Hi Alexandre,
>>>>>
>>>>> This seems to be a bug. I am not sure why I missed the 'n' on the name
>>>>> either. As it seems that this function has never worked, we should fix the
>>>>> name as well. The solution is simple as follows:
>>>>>
>>>>> extra/expr~/vexp_fun.c
>>>>>
>>>>> 188c188
>>>>>
>>>>> <         {"copysign",    ex_copysign,    2},
>>>>>
>>>>> ---
>>>>>
>>>>> >         {"copysig",     ex_copysign,    1},
>>>>>
>>>>>
>>>>> I checked the mailing list (I am sorry that I am not a regular reader)
>>>>> and I see some concerns about the maintenance of the code. I am happy to
>>>>> fix the problems and I thought I sent you a fix for the last problem you
>>>>> had found in 2009. Can somebody point me to a document or a webpage that
>>>>> explains what the best way is to introduce new changes to the pd source
>>>>> base.  Miller, should I pass the fixes to you, or is there another
>>>>> repository?
>>>>>
>>>>> In the meanwhile, if there are other bugs in expr that anybody else
>>>>> knows, please send them to me and I will fix them as soon as I can.
>>>>>
>>>>> best,
>>>>> Shahrokh
>>>>>
>>>>> On Sun, Jun 7, 2015 at 12:57 PM, Alexandre Torres Porres <
>>>>> porres at gmail.com> wrote:
>>>>>
>>>>>> hi there, I was checking the source of expr (find it attached) and
>>>>>> saw this "copysign" function that I needed for a formula, but I can't get
>>>>>> it to work/load.
>>>>>>
>>>>>> I'm trying something like [expr copysign($f1)] and it's not
>>>>>> happening. The expr manual page in http://yadegari.org/expr/expr.html
>>>>>> tells about this function as well, here it is:
>>>>>>
>>>>>> copysign()
>>>>>> 1
>>>>>> copy sign of a number(added in version 0.4)
>>>>>>
>>>>>> So it seems I'm supposedly doing the right thing... is it a bug? I'm
>>>>>> on extended 0.42 and it says that it's expr version 0.4 when it loads.
>>>>>>
>>>>>> cheers
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Shahrokh Yadegari
>>>>> Professor of Composition and Sound Design,
>>>>> Theatre and Dance Department
>>>>> University of California, San Diego
>>>>> Director, Initiative for Digital Exploration of Arts and Science,
>>>>> (IDEAS)
>>>>> California Institute for Telecommunications and Information
>>>>> Technologies (Calit2)
>>>>> Email: sdy at ucsd.edu
>>>>> Web: http://yadegari.org
>>>>> Tel: (858) 822-4113
>>>>> Fax: (858) 534-1080
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> Shahrokh Yadegari
>>> Professor of Composition and Sound Design,
>>> Theatre and Dance Department
>>> University of California, San Diego
>>> Director, Initiative for Digital Exploration of Arts and Science, (IDEAS)
>>> California Institute for Telecommunications and Information Technologies
>>> (Calit2)
>>> Email: sdy at ucsd.edu
>>> Web: http://yadegari.org
>>> Tel: (858) 822-4113
>>> Fax: (858) 534-1080
>>>
>>>
>>
>
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