Re: [Discuss-gnuradio] Problems passing the control between blocks - message passing

[Jose Torres Diaz]

Hi John, 

Also, I am trying to use boost::this_thread::yield() between blocks, but when I add a third block into the chain, the control passes between BLOCK 1 <-> BLOCK 2. When they finish, the control is passed to BLOCK 3.

Thanks again for your suggestions, 

Jose

On Mon, Oct 22, 2012 at 9:17 AM, Jose Torres Diaz <address@hidden> wrote:

Hi John,

Please, find attached the codes (.cc) for BLOCK 1 and BLOCK 2. I'm still unable to control the correct order of them, when I generated an infinite loop.

Thanks a lot for your help in this issue,

Regards,

Jose

On Thu, Oct 18, 2012 at 9:58 AM, John Malsbury <address@hidden> wrote:

Can you send me the files?

-John

On Wed, Oct 17, 2012 at 4:16 PM, Jose Torres Diaz <address@hidden> wrote:

Hi John,

Yes, I also checked the examples in your branch. In regards to your questions.

1. BLOCK 2 is processing the data from BLOCK 1, but only when BLOCK 1 has finished the routine "N times". Let me post a piece of code from BLOCK 1:

int work(
        const InputItems &,
        const OutputItems &
    ){
     
             

        for (int i = 0; i < d_pkt_len; i++) {
               if (d_mode == 2)
          { elements[i] = ((i % d_pkt_len) + d_num_pkts_output) & 0xff;
                  }
        else if (d_mode == 0)
          {elements[i]=0;
                 }
             else // ones
        {elements[i]=0xFF;
        }
        num_output++;
      } //End of for
      d_num_pkts_output++;

      //(4.1) adding data into the dictionary
      dictionary = pmt::pmt_dict_add(dictionary, data_key, vector_data);
      std::cout << std::endl << "(4) Now, the dictionary is" << dictionary <<std::endl;
  

      //Posting a message downstream
      this->post_msg(0, AMSG_KEY, dictionary, _d_my_unique_id);
      std::cout << std::endl << "posting the message downstream " <<std::endl;
       
      return -1;  // <--The problem seems to be here
    
   }


2. N is the number of packet that I want to transmit from BLOCK 1. In my code, I'm using the variable d_max_pkts. So, when d_num_pkts_output >= d_max_pkts, the program stops:

    if (d_num_pkts_output >= d_max_pkts)
      return 0;

3. Yes, my BLOCK 1 is as follows:

block(
          //"gr uhd amsg source",
          "BLOCK 1",
            gr_make_io_signature(0, 0, 0),
            gr_make_io_signature(0, 0, 0),
            msg_signature(false, 1)


Thanks again for your advice,

Regards,

Jose

On Wed, Oct 17, 2012 at 5:14 PM, John Malsbury <address@hidden> wrote:

So, block 2 is never processing the data?  What are you using to set the "N"?  Does the uhd_amsg_source have the same i/o as the original block - no inputs, one msg output?

If you're looking to something to generate periodic msg's with arbirtrary key and value, the heart_beat block in my pre-cog branch might help...

-John

On Tue, Oct 16, 2012 at 11:34 PM, Jose Torres Diaz <address@hidden> wrote:

Hi John,

I wrote the code in C++ based on UHD_AMsg_source.cc, provided in GRExtras. In my work function, I've finished it using return -1 (ie. the block has finished processing correctly) as shown below:

int work(
        const InputItems &,
        const OutputItems &
    ){
      //work definition here (ie. generate a packet and post downstream)
      return -1; //done running, work done status
    }

However, in that way the block in GNU Radio Companion runs only once. The other possibility is not to use "return" at all, but in that case what I have is:

1. BLOCK 1 generates a packet
2. BLOCK 1 post the packet downstream

Step 1 and 2 repeats "N times". When finishes, it gives the control to BLOCK 2 to process the message. However, I need a sequence as follows:

1. BLOCK 1 generates a packet
2. BLOCK 1 post the packet downstream
3. BLOCK 2 process the packet
4. BLOCK 2 post the message again downstream and so on...

Step 1 to 4 should repeat "N times".

Thanks again for your help,

Jose

On Wed, Oct 17, 2012 at 4:52 PM, John Malsbury <address@hidden> wrote:

Jose,

Try a while(1) with a block and  a blocking call to pop msg's off the queue:

self.pop_msg_queue()

Should help you avoid the return -1

Or maybe I've misunderstood your problem...?

-John

On Tue, Oct 16, 2012 at 11:18 PM, Jose Torres Diaz <address@hidden> wrote:

Hi All,

I'm working with 2 blocks that I've created using "UHD_AMsg_Source" as a reference model. In these blocks, I am passing pmt_dict type as messages, ie:

 this->post_msg(0, AMSG_KEY, dictionary,_id);

Where, dictionary contains data/metadata that I can read in the next block downstream.

BLOCK 1  -- (pmt_dict included in the message) -->  BLOCK 2

The blocks are working ok, but the problem is that when I want to generate several packets and post them downstream, BLOCK 1 runs until finishes and then BLOCK 2 takes the control until finishes. The problem is the "return" sentence in my work function. I did 2 possible ways

Option 1: Using -1

work {
//work here
return -1
}
 
In this way BLOCK 1 stops working after one iteration and it does not run as many times as I want.

Option 1: Not using return

work {
//work here
}

In this way BLOCK 1 runs many times and posts messages downstream all those times, but it gives the control to BLOCK 2 when it finishes. Then, BLOCK 2 takes the messages from the message queue. However, this implementation is not useful for me. BLOCK 1 should post a message downstream and then, BLOCK 2 takes the message and work with the packet.

Any suggestion is welcome, thanks a lot for your time,

Regards,

Jose

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