Re: [Discuss-gnuradio] Complex numbers in math operations

[Michael Dickens]

Hi Vipin - You're doubly dereferencing IdealFMCW. I think your code should read:

{{{

        *Tx1 = *Tx1 + (IdealFMCW[tapIdx]) * (*hTx1); 

}}}

because the [tapIdx] already dereferences the gr_complex* (IdealFMCW) to be just gr_complex. The error provided by your compiler isn't very helpful. Clang's error reads:

{{{

error: indirection requires pointer operand ('gr_complex' (aka 'complex<float>') invalid)

}}}

which at least gives a clue about the extra dereference but it's great either. Hope this helps! - MLD

On Fri, Jun 9, 2017, at 01:57 AM, Vipin Sharma wrote:

I have a custom block with some input streams being declared as gr_complex type as shown here:

Control_impl::general_work (int noutput_items,

                       gr_vector_int &ninput_items,

                       gr_vector_const_void_star &input_items,

                       gr_vector_void_star &output_items)

    {

      const gr_complex *hTx1 = (const gr_complex *) input_items[0];

      const gr_complex *hTx2 = (const gr_complex *) input_items[1];

      const gr_complex *IdealFMCW = (const gr_complex *) input_items[2];

Later on I use IdealFMCW as follows:

       for(tapIdx=0; tapIdx<TapSize; tapIdx++) {

        *Tx1 = *Tx1 + *(IdealFMCW[tapIdx]) * (*hTx1); 

When I do make, I get compile errors:

error: no match for ‘operator*’ (operand type is ‘const gr_complex {aka const std::complex<float>}’)

         *Tx1 = *Tx1 + *(IdealFMCW[tapIdx]) * (*hTx1); 

I am simply trying to de-reference the pointer (defined by IdealFMCW[tapIdx]) and use the value. What am I not doing right?