Re: [Discuss-gnuradio] Transcendental block itemsize mismatch (no custom blocks)

[Martin Braun]

For your type, try 'complex_float' instead of 'complex_double'. The latter is unfortunately mapped to 'complex' (in the GRC options), which is not a common data type in GNU Radio.

For 3.9, I would even suggest changing the default from complex_double to complex_float -- if you want to submit a PR, there you go :)

-- M

On Thu, Oct 17, 2019 at 2:02 PM Nicholas Bruce <address@hidden> wrote:

Hi all,

I am running GNU Radio 3.7.13.4 and working in GNU Radio Companion on Ubuntu 18.04

I have a very simple flowgraph where I have a source of type complex (I've tried both a signal source and a constant source) which I connect to a transcendental block (of type complex) and then output to a sink of type complex (I don't think anything after the transcendental block matters).

I have tried the transcendental block with functions "sin", "cos" and "exp". When I execute the flowgraph, I get the error:

ValueError: itemsize mismatch: sig_source_c0:0 using 8, transcendental0:0 using 16

The transcendental block is meant to take any cmath functions so I thought perhaps there were different function names for the complex and float cases? Something like "ccos" or csin" but I haven't seen any on the list of available functions.

I have seen similar questions where people are creating custom blocks and OOT modules and seeing this problem. They have often used the wrong datatype (numpy complex 32 instead of 64).

I am not using any custom blocks. This problem is with stock/shipped GR blocks.

Any help is appreciated!

Nick

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