[PD] reading arrays from an external

[oscar pablo di liscia]

Many thanks. I am trying to load in a table spectral data to make
these data available to an arbitrary number of "readers". I will see
how I can deal with this using the tabread and tabwrite externals.
Also, it is not clear to me the meaning and the use of the function:
"garray_usedindsp" and what is the effect of it. Of course I know that
the code is available, but if if somebody can give me a brief idea,
I will save a lot of time.
Best

Oscar Pablo Di Liscia

2015-09-21 4:27 GMT-03:00 IOhannes m zmoelnig <zmoelnig at iem.at>:

> On 2015-09-21 00:22, oscar pablo di liscia wrote:
> > Hi list.
> > I have a question on allocating data and reading it through an external.
> > As I have seen so far, the externals that reads arrays, as tabread,
> allocate
> > the data in their own memory space. As far as I can understand, this
> result
> > in a "double allocation" of the data. One in the array itself and the
> other
> > one in the
> > internal memory space of the instance of the tabread external.
> > The point is that I would like to use an array to hold in memory a
> > considerable
> > amount of data and to make it available to an arbitrary "reader" objects
> > without the need of allocating the data again in each one of the readers.
> > Is it possible to write an external that that reads data from an array
> "on
> > the fly"
> > without the need of allocating the data in its own memory space?
> > Any help will be most appreciate.
>
> virtually all¹ objects accessing table data reference the data
> "directly" using the "garray_getfloatwords()" function to get a pointer
> where the array stores its data.
> this does not involve any double allocation at all.
> it is also the only sane way to always use up-to-date data: if the user
> modifies the data via [tabwrite] or whatever, there is no way to signal
> the table consumers that the table data has changed (so that they can
> copy the relevant new data into their local copy), so the consumer must
> use the changed data directly.
>
> which objects have you found that proxy the data?
>
> gfasd,rt
> IOhannes
>
>
>
> ¹ i seem to remember that [partconv~] does copy the data during
> DSP-graph recompilation, mainly because it does some heavy processing on
> the data (FFTs and what not), which it doesn't want to do for each
> signal block. i might be mistaken though.
>
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