a-rate if

[Joseph Sanger]

Hello again list,

I really want to do something like this:

        if a1>a2 then

        ; some stuff

        endif

But if-statements don't work with a-rate variables.

I'm doing non-real-time stuff with ksmps=1, and I even tried changing
all variables to k-rate and then using a(kout) at the end but ended up
having all sorts of other difficulties, which I haven't got to the
bottom of yet.

The only workaround I have so far is to copy the arate to krate using
max_k (which is the only opcode I could find to do this) and then
compare them, but I feel like I'm going round the houses a bit, so:

1. Is there a simpler / more elegant solution?

2. Is there another opcode which I've overlooked? Like the 'a' opcode,
but in reverse; something which simply copies the a-rate variable to
k-rate every ksmps, without averaging or finding the maximum.

3. Is there any reason why 'if' can't be made to accept a-rate variables
in the (near!) future?

Yours gratefully,

Joe


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Andres Cabrera]

Hi,
If you are using ksmps=1 then k-rate variables are the same as a-rate variables. If something is amiss, it's a bug. If you can nail it down, please report it.

Cheers,
Andrés

On Mon, Jul 7, 2008 at 9:12 AM, Joseph Sanger <joseph.sanger@...> wrote:

Hello again list,

I really want to do something like this:

       if              a1>a2   then

       ; some stuff

       endif

But if-statements don't work with a-rate variables.

I'm doing non-real-time stuff with ksmps=1, and I even tried changing all variables to k-rate and then using a(kout) at the end but ended up having all sorts of other difficulties, which I haven't got to the bottom of yet.

The only workaround I have so far is to copy the arate to krate using max_k (which is the only opcode I could find to do this) and then compare them, but I feel like I'm going round the houses a bit, so:

1. Is there a simpler / more elegant solution?

2. Is there another opcode which I've overlooked? Like the 'a' opcode, but in reverse; something which simply copies the a-rate variable to k-rate every ksmps, without averaging or finding the maximum.

3. Is there any reason why 'if' can't be made to accept a-rate variables in the (near!) future?

Yours gratefully,

Joe


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Joseph Sanger]

Hi Andres,

OK that's good to know. I'll do my best to nail it down, I imagine it's
a typo somewhere - I'll let you know if not. Right now it's making my
head hurt so I'm going to bed.

Joe

Andres Cabrera wrote:

> Hi,
> If you are using ksmps=1 then k-rate variables are the same as a-rate
> variables. If something is amiss, it's a bug. If you can nail it down,
> please report it.
>
> Cheers,
> Andrés
>
> On Mon, Jul 7, 2008 at 9:12 AM, Joseph Sanger <joseph.sanger@...
> <mailto:joseph.sanger@...>> wrote:
>
>     Hello again list,
>
>     I really want to do something like this:
>
>            if              a1>a2   then
>
>            ; some stuff
>
>            endif
>
>     But if-statements don't work with a-rate variables.
>
>     I'm doing non-real-time stuff with ksmps=1, and I even tried
>     changing all variables to k-rate and then using a(kout) at the end
>     but ended up having all sorts of other difficulties, which I haven't
>     got to the bottom of yet.
>
>     The only workaround I have so far is to copy the arate to krate
>     using max_k (which is the only opcode I could find to do this) and
>     then compare them, but I feel like I'm going round the houses a bit, so:
>
>     1. Is there a simpler / more elegant solution?
>
>     2. Is there another opcode which I've overlooked? Like the 'a'
>     opcode, but in reverse; something which simply copies the a-rate
>     variable to k-rate every ksmps, without averaging or finding the
>     maximum.
>
>     3. Is there any reason why 'if' can't be made to accept a-rate
>     variables in the (near!) future?
>
>     Yours gratefully,
>
>     Joe
>
>
>     Send bugs reports to this list.
>     To unsubscribe, send email sympa@...
>     <mailto:sympa@...> with body "unsubscribe csound"
>
>

Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Michael Bechard]

For handling a-to-k-rate manipulations I use downsamp to get from a to k-rate, and upsamp going the other way. I think downsamp does use averaging (or something like that?), but at ksmps=1 it won't matter.

Michael Bechard



----- Original Message ----
From: Joseph Sanger <joseph.sanger@...>
To: csound@...
Sent: Monday, July 7, 2008 9:12:00 AM
Subject: [Csnd] a-rate if

Hello again list,

I really want to do something like this:

    if        a1>a2    then

    ; some stuff

    endif

But if-statements don't work with a-rate variables.

I'm doing non-real-time stuff with ksmps=1, and I even tried changing
all variables to k-rate and then using a(kout) at the end but ended up
having all sorts of other difficulties, which I haven't got to the
bottom of yet.

The only workaround I have so far is to copy the arate to krate using
max_k (which is the only opcode I could find to do this) and then
compare them, but I feel like I'm going round the houses a bit, so:

1. Is there a simpler / more elegant solution?

2. Is there another opcode which I've overlooked? Like the 'a' opcode,
but in reverse; something which simply copies the a-rate variable to
k-rate every ksmps, without averaging or finding the maximum.

3. Is there any reason why 'if' can't be made to accept a-rate variables
in the (near!) future?

Yours gratefully,

Joe


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"



     


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Mark Van Peteghem-2]

No, it's not that easy. When ksmps=1, opcodes that require either k-rate
or a-rate for a certain argument, still don't accept the other. E.g.

    afil butterlp asig, afreq

doesn't work. You continuously need upsamp (or interp) and downsamp to
switch between the two rates.

Andres Cabrera schreef:

> Hi,
> If you are using ksmps=1 then k-rate variables are the same as a-rate
> variables. If something is amiss, it's a bug. If you can nail it down,
> please report it.
>
> Cheers,
> Andrés
>
> On Mon, Jul 7, 2008 at 9:12 AM, Joseph Sanger
> <joseph.sanger@... <mailto:joseph.sanger@...>> wrote:
>
>     Hello again list,
>
>     I really want to do something like this:
>
>            if              a1>a2   then
>
>            ; some stuff
>
>            endif
>
>     But if-statements don't work with a-rate variables.
>
>     I'm doing non-real-time stuff with ksmps=1, and I even tried
>     changing all variables to k-rate and then using a(kout) at the end
>     but ended up having all sorts of other difficulties, which I
>     haven't got to the bottom of yet.
>
>     The only workaround I have so far is to copy the arate to krate
>     using max_k (which is the only opcode I could find to do this) and
>     then compare them, but I feel like I'm going round the houses a
>     bit, so:
>
>     1. Is there a simpler / more elegant solution?
>
>     2. Is there another opcode which I've overlooked? Like the 'a'
>     opcode, but in reverse; something which simply copies the a-rate
>     variable to k-rate every ksmps, without averaging or finding the
>     maximum.
>
>     3. Is there any reason why 'if' can't be made to accept a-rate
>     variables in the (near!) future?
>
>     Yours gratefully,
>
>     Joe
>
>
>     Send bugs reports to this list.
>     To unsubscribe, send email sympa@...
>     <mailto:sympa@...> with body "unsubscribe csound"
>
>

--
  Mark
  _________________________________________
  When you get lemons, you make lemonade.
  When you get hardware, you make software.



Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Andres Cabrera]

True. I meant that k-rate variables are updated at the same rate as a-rate variables. If you use upsamp and downsamp to convert between one and the other, you get the same signal.

Cheers,
Andrés

On Mon, Jul 7, 2008 at 10:12 AM, Mark Van Peteghem <Mark.Van.Peteghem@...> wrote:

No, it's not that easy. When ksmps=1, opcodes that require either k-rate or a-rate for a certain argument, still don't accept the other. E.g.

  afil butterlp asig, afreq

doesn't work. You continuously need upsamp (or interp) and downsamp to switch between the two rates.

Andres Cabrera schreef:

Hi,
If you are using ksmps=1 then k-rate variables are the same as a-rate variables. If something is amiss, it's a bug. If you can nail it down, please report it.

Cheers,
Andrés

On Mon, Jul 7, 2008 at 9:12 AM, Joseph Sanger <joseph.sanger@... <mailto:joseph.sanger@...>> wrote:

   Hello again list,

   I really want to do something like this:

          if              a1>a2   then

          ; some stuff

          endif

   But if-statements don't work with a-rate variables.

   I'm doing non-real-time stuff with ksmps=1, and I even tried
   changing all variables to k-rate and then using a(kout) at the end
   but ended up having all sorts of other difficulties, which I
   haven't got to the bottom of yet.

   The only workaround I have so far is to copy the arate to krate
   using max_k (which is the only opcode I could find to do this) and
   then compare them, but I feel like I'm going round the houses a
   bit, so:

   1. Is there a simpler / more elegant solution?

   2. Is there another opcode which I've overlooked? Like the 'a'
   opcode, but in reverse; something which simply copies the a-rate
   variable to k-rate every ksmps, without averaging or finding the
   maximum.

   3. Is there any reason why 'if' can't be made to accept a-rate
   variables in the (near!) future?

   Yours gratefully,

   Joe


   Send bugs reports to this list.
   To unsubscribe, send email sympa@...

   <mailto:sympa@...> with body "unsubscribe csound"

--
 Mark
 _________________________________________
 When you get lemons, you make lemonade.
 When you get hardware, you make software.

Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[John Lato]

Joseph Sanger wrote:

 > 2. Is there another opcode which I've overlooked? Like the 'a' opcode,
 > but in reverse; something which simply copies the a-rate variable to
 > k-rate every ksmps, without averaging or finding the maximum.

In general this isn't possible.  Since an a-rate variable is an array of data (with
length ksmps), it's clear that to convert from a-rate to k-rate you need some sort of
aggregating function (e.g. calculate the average or maximum).  In the special case of
ksmps=1 aggregating is unnecessary, but both averaging and taking the maximum would
return the same value then anyway, so it doesn't make any difference.

I agree this can seem inelegant to many csound users, but if you think of how the
orchestra is interpreted by csound it should be clear.

 >
 > 3. Is there any reason why 'if' can't be made to accept a-rate variables
 > in the (near!) future?
 >

I can think of several.  Again, understanding that an a-rate variable is really an
array should make it clear.  Csound operates at the k-rate.  'if' accepting a-rate
variables only makes syntactic sense in the case of ksmps=1, all other values would
mean creating separate execution paths within a single a-variable array.  I doubt
that could be implemented in any fashion that doesn't defeat the purpose of the
k-rate (which means that ksmps=1 is what you really want anyway).

Working at ksmps=1, I would use max_k as you are already.  Downsamp and interp are
other options.

John W. Lato
Sarah and Ernest Butler School of Music
The University of Texas at Austin
1 University Station E3100
Austin, TX 78712-0435
[phone]


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Joseph Sanger]

Thanks everyone for all of your replies, they've clarified matters
considerably (and given me a more in-depth knowledge of csound's
internals!). I'll check out downsamp and interp as well, to see if they
seem more appropriate.

Thanks again,

Joe

John Lato wrote:

>
> Joseph Sanger wrote:
>
>  > 2. Is there another opcode which I've overlooked? Like the 'a' opcode,
>  > but in reverse; something which simply copies the a-rate variable to
>  > k-rate every ksmps, without averaging or finding the maximum.
>
> In general this isn't possible.  Since an a-rate variable is an array of
> data (with length ksmps), it's clear that to convert from a-rate to
> k-rate you need some sort of aggregating function (e.g. calculate the
> average or maximum).  In the special case of ksmps=1 aggregating is
> unnecessary, but both averaging and taking the maximum would return the
> same value then anyway, so it doesn't make any difference.
>
> I agree this can seem inelegant to many csound users, but if you think
> of how the orchestra is interpreted by csound it should be clear.
>
>  >
>  > 3. Is there any reason why 'if' can't be made to accept a-rate variables
>  > in the (near!) future?
>  >
>
> I can think of several.  Again, understanding that an a-rate variable is
> really an array should make it clear.  Csound operates at the k-rate.  
> 'if' accepting a-rate variables only makes syntactic sense in the case
> of ksmps=1, all other values would mean creating separate execution
> paths within a single a-variable array.  I doubt that could be
> implemented in any fashion that doesn't defeat the purpose of the k-rate
> (which means that ksmps=1 is what you really want anyway).
>
> Working at ksmps=1, I would use max_k as you are already.  Downsamp and
> interp are other options.
>
> John W. Lato
> Sarah and Ernest Butler School of Music
> The University of Texas at Austin
> 1 University Station E3100
> Austin, TX 78712-0435
> [phone]
>
>
> Send bugs reports to this list.
> To unsubscribe, send email sympa@... with body "unsubscribe
> csound"
>

Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Oeyvind Brandtsegg-2]

If you write an UDO, you can use a "local" ksmps=1, so you don't have
to run everything at such a high k-rate.
Oeyvind

2008/7/7, Joseph Sanger <joseph.sanger@...>:

> Thanks everyone for all of your replies, they've clarified matters
> considerably (and given me a more in-depth knowledge of csound's
> internals!). I'll check out downsamp and interp as well, to see if they seem
> more appropriate.
>
> Thanks again,
>
> Joe
>
>
> John Lato wrote:
> >
> > Joseph Sanger wrote:
> >
> >  > 2. Is there another opcode which I've overlooked? Like the 'a' opcode,
> >  > but in reverse; something which simply copies the a-rate variable to
> >  > k-rate every ksmps, without averaging or finding the maximum.
> >
> > In general this isn't possible.  Since an a-rate variable is an array of
> data (with length ksmps), it's clear that to convert from a-rate to k-rate
> you need some sort of aggregating function (e.g. calculate the average or
> maximum).  In the special case of ksmps=1 aggregating is unnecessary, but
> both averaging and taking the maximum would return the same value then
> anyway, so it doesn't make any difference.
> >
> > I agree this can seem inelegant to many csound users, but if you think of
> how the orchestra is interpreted by csound it should be clear.
> >
> >  >
> >  > 3. Is there any reason why 'if' can't be made to accept a-rate
> variables
> >  > in the (near!) future?
> >  >
> >
> > I can think of several.  Again, understanding that an a-rate variable is
> really an array should make it clear.  Csound operates at the k-rate.  'if'
> accepting a-rate variables only makes syntactic sense in the case of
> ksmps=1, all other values would mean creating separate execution paths
> within a single a-variable array.  I doubt that could be implemented in any
> fashion that doesn't defeat the purpose of the k-rate (which means that
> ksmps=1 is what you really want anyway).
> >
> > Working at ksmps=1, I would use max_k as you are already.  Downsamp and
> interp are other options.
> >
> > John W. Lato
> > Sarah and Ernest Butler School of Music
> > The University of Texas at Austin
> > 1 University Station E3100
> > Austin, TX 78712-0435
> > [phone]
> >
> >
> > Send bugs reports to this list.
> > To unsubscribe, send email sympa@... with body "unsubscribe
> csound"
> >
> >
>
>
> Send bugs reports to this list.
> To unsubscribe, send email sympa@... with body "unsubscribe
> csound"
>

Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[jpff]

One could easier create an opcode that takes an audio signal and gives
a k-value as either a "random" value in the kperiod, or the first
value.  Is it worthwhile?
==John ffitch


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"

[Matt J. Ingalls]

doesn't downsamp do the first value
with window size of 0 (default)

rand value might be cool.
also max and min

________________________________________
From: jpff [jpff@...]
Sent: Saturday, July 19, 2008 12:18 PM
To: csound@...
Cc: csound@...
Subject: [Csnd] Re: Re: a-rate if

One could easier create an opcode that takes an audio signal and gives
a k-value as either a "random" value in the kperiod, or the first
value.  Is it worthwhile?
==John ffitch


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"


Send bugs reports to this list.
To unsubscribe, send email sympa@... with body "unsubscribe csound"