Hi all,
I’m having a problem trying to use gr_vector_float type.
I don’t have
any problem to work with streams, but when I try to create a block that
takes a
vector of float numbers on its input and produces a vector of float
numbers on
its output (N:N) I always receive this error:
ValueError: itemsize mismatch:
stream_to_vector(2):0 using 4096, xcor_ff(4):0 using 4
I understood this error
is caused by different vectors’ size, but I don’t understand what I did
wrong
in my code.
This is c++ source of my block (I’m trying to create a block that
compute the autocorrelation of its input vector):
############################################################################################################
/* -- c++ -- /
/
- Copyright 2005 Free Software Foundation, Inc.
This file is part of GNU Radio
*
- GNU Radio is free software; you can
redistribute it and/or modify - it under the terms of the GNU General Public
License as published by - the Free Software Foundation; either version 3, or
(at your option) - any later version.
- GNU Radio is distributed in the
hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the
implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the - GNU General Public License for more details.
- You should have
received a copy of the GNU General Public License - along with GNU Radio; see
the file COPYING. If not, write to - the Free Software Foundation, Inc., 51
Franklin Street, - Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include “config.h”
#endif
#include <howto_xcor_ff.h>
#include
<gr_io_signature.h>
#include <gri_fft.h>
#include <math.h>
#include
#include
#include
#include <string.h>
#include <gr_types.h>
howto_xcor_ff_sptr howto_make_xcor_ff (int fftsize)
{
return
howto_xcor_ff_sptr (new howto_xcor_ff (fftsize));
}
howto_xcor_ff::
howto_xcor_ff (int fftsize)
: gr_sync_block (“xcor_ff”,
gr_make_io_signature (1, 1, sizeof (float)),
gr_make_io_signature (1,
1, sizeof (float)))
{
d_fftsize = fftsize;
d_fwdfft = new gri_fft_real_fwd
(d_fftsize);
d_invfft = new gri_fft_real_rev(d_fftsize);
}
howto_xcor_ff::
~howto_xcor_ff ()
{
delete d_fwdfft;
delete d_invfft;
}
int
howto_xcor_ff::
work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const gr_vector_float *in = (const
gr_vector_float *) input_items[0];
gr_vector_float *out = (gr_vector_float *)
output_items[0];
unsigned int input_data_size = input_signature()-
sizeof_stream_item (0);
unsigned int output_data_size = output_signature()-
sizeof_stream_item (0);
int j,i=0;
while (i++ < noutput_items)
{
memcpy(d_fwdfft->get_inbuf(), in, input_data_size);
memcpy
(d_invfft->get_inbuf(), in, input_data_size);
d_fwdfft->execute(); //
compute fwd xform
float scale = 1.0 / d_fftsize;
for (j = 0; j <
d_fftsize; j++)
d_invfft->get_inbuf()[j] = d_invfft->get_outbuf()[j] *
scale;
d_invfft->execute(); // compute inv xform
for (j = 0; j <
d_fftsize; j++)
d_invfft->get_inbuf()[j] = d_fwdfft->get_outbuf()[j] *
d_invfft->get_outbuf()[j];
d_invfft->execute(); // compute inv xform
// copy result to output
memcpy(out, d_invfft->get_outbuf(),
output_data_size);
out += d_fftsize;
in += d_fftsize;
}
return
noutput_items;
}
######################################################################################################
I’m a beginner, so probably my code is full of errors.
Thank you for your
help.
Elettra