Re: Problem with the OOT forecast() method in Python

[George Edwards]

Hi Jeff, thanks for bearing with me. 

When I retested the last approach just now upon receiving your email it works. Earlier, l forgot to take out some extraneous stuff in my code, which broke it. The code snippet I sent implies a one to one relationship between input and output. The forecaster does its job to ensure the number of input samples is at least the same size as the output, but in many instances the input is larger. This, however, will present a problem to the signal processing algorithm I have in mind which requires the post-pending samples (the size of my filter) to the end to the incoming data before upsampling. It seems the forecaster may be too loose in its input/output sample relationship and will mess up my algorithm.

Anyway, if you have any thought on this and do not mind sharing I would appreciate it.

Thank again for your assistance.

George 

On Wed, Oct 12, 2022, 2:58 PM Jeff Long <willcode4@gmail.com> wrote:

The last one looks correct, and would not have given the error you mention above. What happened?

On Wed, Oct 12, 2022 at 4:49 PM George Edwards <gedwards.eng@gmail.com> wrote:

Hi Jeff, thank you very much for the response. 

I tries:

ninput_items_required[0]=[noutput_items]

ninput_items_required=[noutput_items]

and

return [noutput_items]

None of these worked for me.

Regards 

George

On Wed, Oct 12, 2022, 8:07 AM Jeff Long <willcode4@gmail.com> wrote:

For Python, the forecast() function should return a list, containing the number of items required for each input.

On Wed, Oct 12, 2022 at 8:08 AM George Edwards <gedwards.eng@gmail.com> wrote:

Hello GNURadio Community, 

I am getting a TypeError when I fill in the code in the forecast() method in my Gnuradio OOT block design. I know, if I want to interpolate or decimate, I can simply pick the block type in the gr_modtool design menu, however, I would like to develop the capability to design my own. Here is how I fill in the forecast() method in Python to do either decimation or interpolation:

ninput_items_required[0] = noutput_items*self.sps  # for decimation

OR

ninput_items_required[0] = noutput_items/self.sps  # for interpolation

On running the flowgraph in GRC Console I see TypeError: 'int' object does not support item assignment.

Will appreciate any suggestion to fix this problem.

George