# Testing block written in block **URL:** \ **Category:** GNU Radio\ **Created:** [June 18, 2014, 11:01am UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441 "2014-06-18T11:01:44Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![jason\_sam](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7993a0/32.png) [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Post date:** [June 18, 2014, 11:01am UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441/1 "2014-06-18T11:01:44Z")
Hi I’m new to GNU radio and is trying to develop my own block. I want to develop a block that intake a vector and out put sum of the vector elements. I used the out of tree module and followed tutorial using python code. How should be the arguments of blocks.vector\_source\_f to be given if i am inputting vector stream of four integers is used. the python code and test file is given below. Code: def **init** (self, in\_arg): gr.sync\_block. **init** (self, name=“sream\_ff”, in\_sig=[(numpy.float32, 4)], out\_sig=[numpy.float32]) def work(self, input\_items, output\_items): in0 = input\_items[0] out = output\_items[0] # \<+signal processing here+\> out[:] = sum(in0)\*in\_arg return len(output\_items[0]) Test code: def test\_001\_t (self): src\_data = (([1,1,1,1],4), ([1,2,3,4],4)) expected\_result = (8, 20) src = blocks.vector\_source\_f(src\_data) fxn = sream\_ff(2) snk = blocks.vector\_sink\_f() # set up fg self.tb.connect(src, fxn) self.tb.connect(fxn, snk) self.tb.run () # check data result\_data = snk.data () self.assertFloatTuplesAlmostEqual (expected\_result, result\_data, 6) ---
**Author:** ![sreena\_p\_h](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/47e85d/32.png) [@sreena\_p\_h](https://www.ruby-forum.com/u/sreena_p_h)\ **Post date:** [June 18, 2014, 11:31am UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441/2 "2014-06-18T11:31:27Z")
Hi Sreena, a few quick remarks: - where does in\_arg come from? - in0 should be seen as a vector of vectors. It’s often useful to “print in0.shape”, if in0 is a numpy array - potential mistake: just returning len(input\_items[0]). Be _very_ aware of what the return value of a work call should be (i.e. the number of items produced). I think you meant to calculate but one sum, is that right? Greetings, Marcus ---
**Author:** ![sreena\_p\_h](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/47e85d/32.png) [@sreena\_p\_h](https://www.ruby-forum.com/u/sreena_p_h)\ **Post date:** [June 18, 2014, 12:01pm UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441/3 "2014-06-18T12:01:10Z")
On Wed, Jun 18, 2014 at 4:57 PM, sreena p h [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi > > I’m new to GNU radio and is trying to develop my own block. I want to > develop a block that intake a vector and out put sum of the vector > elements. I used the out of tree module and followed tutorial using python > code. How should be the arguments of blocks.vector\_source\_f to be given if > i am inputting vector stream of four integers is used. the python code and > test file is given below. Does your intake vectors have fixed-length or variable length? If they are variable length, then your sream\_ff block won’t be very useful in graphical GRC flowgraph, because there the vector streams are usually fixed-length. If they are fixed-length, then your problem could be easily solved; just create sream\_ff as a decimator block. ---
**Author:** ![sreena\_p\_h](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/47e85d/32.png) [@sreena\_p\_h](https://www.ruby-forum.com/u/sreena_p_h)\ **Post date:** [June 18, 2014, 3:15pm UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441/4 "2014-06-18T15:15:29Z")
From: discuss-gnuradio-bounces+sean.nowlan=removed\_email\_address@domain.invalid [[mailto:discuss-gnuradio-bounces+sean.nowlan=removed\_email\_address@domain.invalid](mailto:discuss-gnuradio-bounces+sean.nowlan=removed_email_address@domain.invalid)] On Behalf Of Activecat Sent: Wednesday, June 18, 2014 5:59 AM To: removed\_email\_address@domain.invalid Cc: sreena p h Subject: Re: [Discuss-gnuradio] testing block written in block On Wed, Jun 18, 2014 at 4:57 PM, sreena p h \ wrote: Hi I’m new to GNU radio and is trying to develop my own block. I want to develop a block that intake a vector and out put sum of the vector elements. I used the out of tree module and followed tutorial using python code. How should be the arguments of blocks.vector\_source\_f to be given if i am inputting vector stream of four integers is used. the python code and test file is given below. Does your intake vectors have fixed-length or variable length? If they are variable length, then your sream\_ff block won’t be very useful in graphical GRC flowgraph, because there the vector streams are usually fixed-length. If they are fixed-length, then your problem could be easily solved; just create sream\_ff as a decimator block. If you’d rather use stock GR blocks or you would like a flowgraph with identical functionality, you can hook up a Vector to Stream block (with num\_items=vector\_length) to an Integrate block (with decimation=vector\_length). … vector\_length = 10 self.vec2stream = blocks.vector\_to\_stream(gr.sizeof\_gr\_complex, vector\_length) self.integrate = blocks.integrate\_cc(vector\_length) self.connect((self.vec2stream, 0), (self.integrate, 0)) … Sean ---
**Author:** ![sreena\_p\_h](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/47e85d/32.png) [@sreena\_p\_h](https://www.ruby-forum.com/u/sreena_p_h)\ **Post date:** [June 19, 2014, 5:37am UTC](https://www.ruby-forum.com/t/testing-block-written-in-block/230441/5 "2014-06-19T05:37:50Z")
On Wed, Jun 18, 2014 at 9:14 PM, Nowlan, Sean [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Sean I agree, that the Integrate block is a decimator block that implement this perfectly. Just that she may want to use integrate\_ff rather than integrate\_cc, depending on her needs. Also we are assuming that the intake vectors are fixed in length. ``` int integrate_ff_impl::work(int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) { const float *in = (const float *)input_items[0]; float *out = (float *)output_items[0]; for (int i = 0; i < noutput_items; i++) { out[i] = (float)0; for (int j = 0; j < d_decim; j++) out[i] += in[i*d_decim+j]; } return noutput_items; } ```