Re: [Discuss-gnuradio] gr-trellis broken on next branch

[Achilleas Anastasopoulos]

Tom,

this requires some further discussion.

We need to know what is the plan with gr-digital.
In some sense EVERYTHING can be included in there,
however this is not a good design.

gr-trellis is not an "implementation of digital
modulation"; it provides digital encoding/decoding techniques
that is important to keep modulation INDEPENDENT.
This was the design philosophy from the first line of
code that went into this and can be seen in all the examples
that are provided: the only aspect of these examples that depends on
a specific modulation is the lookuptable of the constellation.

I would like to welcome more users/developers to comment
on this before we make any significant changes to the module.

best,
Achilleas


On 10/21/2011 3:19 PM, Tom Rondeau wrote:
> On Thu, Oct 20, 2011 at 10:34 PM, Achilleas Anastasopoulos
> <address@hidden <mailto:address@hidden>> wrote:
>
>     After installing the next branch i realized that gr-trellis is not
>     working properly!
>
>     This is due to some work (by Ben Raynwar) that makes gr-trellis
>     dependent on gr-digital (???)
>     In particular the constants related to trellis_metric_type.h cannot be
>     accessed in python/grc
>     as part of the trellis module, but as part of the digital module
>     (this problem appears for instance if you run some of the pccc/sccc
>     examples in gnuradio-examples/grc/trellis).
>
>     This can be an easy fix (import digital in all the grc blocks
>     requiring metric types, and make appropriate changes).
>
>     However I wonder what is the point of making a self-contained
>     module like gr-trellis dependent on another module (gr-digital)
>     If the only reason is to to use the "constellation" object in the
>     "metrics" blocks then these blocks should
>     reside in the gr-digital module instead of the gr-trellis, so that the
>     latter can still be self-contained.
>
>     Ben, can you please explain what is your rational in doing these
>     changes.
>
>     thanks,
>     Achilleas
>
>
>
> Achilleas,
> This was my doing. Ben had moved the metric types into gnuradio-core to
> work with his constellation work, so I moved them over with everything
> else into gr-digital. I then made gr-trellis depend on gr-digital
> because of this. Because gr-trellis is an implementation of digital
> modulation, it makes sense that it should depend on gr-digital.
>
> I made sure that gr-trellis would both build and pass 'make check,' so
> the QA code is obviously not testing all of the proper dependencies and
> cases in gr-trellis. We need to fix that to make sure the applications
> still run as we move stuff around.
>
> Depending on what gr-trellis requires out of gr-digital, we could
> possibly import digital into the trellis module inside of the
> __init__.py file.
>
> Tom