Feature #394

Hello all,

I would like to help expand the C++ API, so I’m attempting to work on
Feature #394 or “Re-implement hierarchical blocks currently living in
blks2
in C++ and put into gnuradio-core/src/lib/hier.” I’ve started on
am_demod.py but this requires optfir, which is also in python, I think
this
should also be available to us C++ users, so i’m converting it too. I’m
new to GnuRadio and would like to know if i’m on the right track before
I
get to far. The files so far are included.

Thank you.

Thanks, I think i’ll work on QA too while i’m at it then.

On Tue, Feb 7, 2012 at 9:52 PM, Andrew D.
[email protected]wrote:

Thank you.

Hi Andrew,
It looks to me like you’re on the right track! Thanks for making a go at
it.

So you seem to have the general style correct in the files that I looked
at. Once it’s coded, the ultimate test is, obviously, to make sure that
the
data produced by any of these guys is the same as is produced by the
Python
versions. This is a good case where the QA code would be useful, so we
would have a set of tests with known output that you could compare
against
the new implementations. Unfortunately, I don’t see an QA for the
optfir,
but it would probably be good to have one.

Tom

On Fri, Feb 24, 2012 at 9:48 PM, Andrew D.
[email protected]wrote:

the API a bit.
Andrew,
Thanks. It might be easier to handle these in stages from a merge
standpoint. Since you’re just adding stuff, it’s easy to add bits and
pieces. If the optfir is ready, we can look into merging it while you
make
another branch for other conversions to C++.

Thanks!
Tom

Ok, I’ve got a branch on github:
https://github.com/glneo/gnuradio-davisaf/tree/optfir with optfir
ported and working in C++, it’s part of gr ( gr.optfir ) like firdes.
This keeps the filter design tools together and allows the old optfir
to still be imported and used until I can get all the examples ported
( which will just be changing “optfir” to “gr.optfir” )

This is kinda just an update, it will probably not be ready for
merging until I finish porting the blks2 hier to C++. Then all the
examples can be done in both python and C++, hopefully this opens up
the API a bit.

Thanks,

All the ‘fix’ comments are there as I was debugging on a remote
machine using github as an intermediate for all my little changes.
I’ll get those merged into real comments before the real merge. Same
for the AM demods, my github optfir branch is for my local testing and
will only include optfir core in the merge to my master repo. I think
I’ll get the QA done over spring break ( next week ) along with more
of blks2.

Which brings me to a few questions, complex_band_pass appears to just
be a complex shifted low pass and therefor does not actually do what
it says it does ( the first band edge is only used to find the center
frequency and not shape the actual band edge ), it is also not used
anywhere ( except the filter design demo ), would anyone object if it
was not included in the C++ version? Also I found a few small bugs in
porting ( for instance ‘desired_ampls = (0, 1)’ I believe should have
been ‘desired_ampls = (0, gain)’ ) so my version might not produce the
exact same results in all cases but produce hopefully more correct
taps.

I figured float to be enough for any practical use, just a little
venting in comments :slight_smile:

Now if only the FSF would get back with me…

~Andrew

On Thu, Mar 8, 2012 at 1:07 PM, Andrew D.
[email protected]wrote:

Thanks,

All the ‘fix’ comments are there as I was debugging on a remote
machine using github as an intermediate for all my little changes.
I’ll get those merged into real comments before the real merge. Same
for the AM demods, my github optfir branch is for my local testing and
will only include optfir core in the merge to my master repo. I think
I’ll get the QA done over spring break ( next week ) along with more
of blks2.

Ah, of course. I understand that mode of working. Not ideal, but
sometimes
necessary. I mistook the state of your branch.

I figured float to be enough for any practical use, just a little
venting in comments :slight_smile:

Now if only the FSF would get back with me…

~Andrew

If there’s any way we can fix those bugs in the Python code, first, I’d
prefer to do that. It’d be nice to make sure both worlds agree.

As for the complex bandpass, we really do need that. I know I’ve used it
in
GNU Radio-based projects before, and I’d bet others have/are, too.
Creating
it as an LPF and the frequency shifting it is a perfectly valid way of
creating this kind of a filter, and it enforces symmetrical transition
bands. It might actually be nice to have a complex bandpass that fully
utilizes the PM algorithm to set the transition bands as desired on
either
ends, but that would only be useful for a special cases.

Thanks,
Tom

On Thu, Mar 8, 2012 at 5:40 PM, Andrew D.
[email protected]wrote:

As for the complex bandpass, we really do need that. I know I’ve used it
in GNU Radio-based projects before, and I’d bet >others have/are, too.
Creating it as an LPF and the frequency shifting it is a perfectly valid
way of creating this kind of a >filter, and it enforces symmetrical
transition bands.

OK, I have the code done It just uses different arguments, Instead of
giving ignored lower transition band starts and stops, it just asks
for the desired center. ( If again no one objects )

So one thing to keep in mind is how we deal with changes in the API of
the
code. Any time there is a change to an interface or arguments list
(unless
it’s a new argument with a default value at the end of the the list),
it’s
an API change, which means that it has to go into the ‘next’ branch.

For this, since we’re talking about removing the Python code and
replacing
it with the C++ versions, it’s probably safer to just say that this will
go
into ‘nex’ and be a part of the 3.6 release.

If there’s any way we can fix those bugs in the Python code, first, I’d
prefer to do that.

If I can remember what they are, most problems didn’t change the
output though ( like unused, redundant, or improper code ).

~Andrew

If they didn’t effect the output, no problem, but since it might
slightly
here or there, it’s just another reason to think about doing this on the
‘next’ branch.

This probably means that you don’t have to do anything more, and I’m
assuming that you branched this off master initially. Since next is a
superset of master, the merge should be pretty easy and clean (conflicts
with autotools files, but that’s expected). I’m just telling you this so
you understand how we thing about these things and making changes to the
code.

Thanks,
Tom

Ok, sounds good, also I’ve only been updating cmake files, is there a
date when the switch from autotools will become official?

~Andrew

On Thu, Mar 8, 2012 at 6:05 PM, Andrew D.
[email protected]wrote:

Ok, sounds good, also I’ve only been updating cmake files, is there a
date when the switch from autotools will become official?

~Andrew

No, no official date. We’re still have a few things in mind to try out
and
work with, so it comes down to a matter of finding the time to complete
it
all. We’ll try to give a head’s up on this when we’ve made a decision.

Tom

As for the complex bandpass, we really do need that. I know I’ve used it in GNU
Radio-based projects before, and I’d bet >others have/are, too. Creating it as an
LPF and the frequency shifting it is a perfectly valid way of creating this kind
of a >filter, and it enforces symmetrical transition bands.

OK, I have the code done It just uses different arguments, Instead of
giving ignored lower transition band starts and stops, it just asks
for the desired center. ( If again no one objects )

If there’s any way we can fix those bugs in the Python code, first, I’d prefer to
do that.

If I can remember what they are, most problems didn’t change the
output though ( like unused, redundant, or improper code ).

~Andrew

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