Re: How to set variable number of inputs/outputs in Python OOT modules

[Tim Huggins]

I am using 3.8.2 and was trying to quickly test it in an embedded python block (the block was displaying that error). If I get a chance I'll compare with a full OOT block.

On Thursday, February 4, 2021, 3:06:58 PM EST, Jeff Long <willcode4@gmail.com> wrote:

The line

  in_sig = gr.io_signature(3,3, gr.sizeof_gr_complex)

just worked for me on both 3.8 and master. Are you using an older version?

On Thu, Feb 4, 2021 at 2:48 PM Tim Huggins <huggins.timothy@yahoo.com> wrote:

I do not believe that you want to encapsulate the call with [ ], even so there may be an issue with that command. I am unsure what the issue is but when I make the call:

in_sig = gr.io_signature(3,3, gr.sizeof_gr_complex)

The error message is: Can't create an instance of your block: object of type 'io_signature_sptr' has no len()

Instead try this:

            in_sig = 3*[np.complex64],

Where 3 will end up being your variable for number of inputs.

Tim

On Thursday, February 4, 2021, 1:23:35 PM EST, George Edwards <gedwards.eng@gmail.com> wrote:

Hi Tim,

Thanks for your suggestion! I just tried it and it does not work. The Python OOT def __init__(self, ....) method requires that one fills in in_sig = xxx and out_sig = xxx.

I tried your suggestion above for variable number of inputs and set:

in_sig = [gr.io_signature(1, -1, gr.sizeof_gr_complex)]

and I leave the yml file as is when I had the static number of inputs (in_sig = [complex64, complex64, complex64]) shown below

inputs:

-      domain:  stream

       dtype:  complex

       multiplicity:  '3'

It gives a TypeError: data type not understood

I tried a bunch of combinations based on the above change you suggested, but GRC kept failing when I tried to run it.!

Thanks again for your suggestion!

Regards,

George

On Thu, Feb 4, 2021 at 8:01 AM Tim Huggins <huggins.timothy@yahoo.com> wrote:

George,

I would recommend taking a look at some of the existing blocks that have variable inputs to accomplish this (especially for the YML file). A YML example for a variable input can be found here:

https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/grc/blocks_multiply_xx.block.yml

I haven't run a test using this line in a python block yet, but two different examples are shown below that I believe should work (or should with some minor tweaks). The first doesn't limit the number of inputs while the second one does (at 8).

gr.io_signature(1, -1, gr.sizeof_gr_complex)) 

gr.io_signature(1, 8, gr.sizeof_float)

I don't know if there is a complete python reference for GNURadio 3.8, but this should be helpful to get you close as well: https://www.gnuradio.org/doc/sphinx-v3.7.9.2/

Good luck,

Tim

On Thursday, February 4, 2021, 12:01:07 AM EST, George Edwards <gedwards.eng@gmail.com> wrote:

Hi Gavin,

Thanks for the information!

Does this mean that if I wanted 3 inputs and 5 outputs and all floating point values, then inside the Python code, I simply set 

 in_sig = [numpy.float32]

 out_sign = [numpy.float32]

And, in the yml file I set:

inputs:

-      domain:  stream

       dtype:  float

       multiplicity:  '3'

outputs: 

-        domain:  stream

         dtype:  float

         multiplicity:  '5'

Would this be correct?

Thanks again for your help!

Regards,

George

On Wed, Feb 3, 2021 at 5:26 PM Gavin Jacobs <apriljunkbox@hotmail.com> wrote:

In 3.7, you would use the <nports> tag, but in 3.8 the trick to setting multiple ins/outs in the YML file, is the keyword "multiplicity". You can see the details of how to configure here:

https://wiki.gnuradio.org/index.php/YAML_GRC

YAML GRC - GNU Radio

Starting with release 3.8, YAML replaces XML as the file format for GNU Radio Companion. This is triggered by switching from Cheetah to Mako as the templating engine, since Cheetah does not support Python 3.

wiki.gnuradio.org