Re: [Discuss-gnuradio] gri_mmse_fir_interpolator_cc::interpolate returns NaN

[Tom Rondeau]

On Tue, Jun 22, 2010 at 11:31 PM, Kyle Zhou <address@hidden> wrote:
> I am testing the gr_mpsk_receiver_cc module using the code attached at the
> end.
> It is gnuradio v3.3.1git-11-ge20160b7 on cygwin 1.7.5-1 with gcc 3.4.4.
> When I run the code, the following error pops up:
> ===========================
> assertion "imu >= 0" failed: file "gri_mmse_fir_interpolator_cc.cc", line
> 67, fu
> nction: gr_complex gri_mmse_fir_interpolator_cc::interpolate(const
> gr_complex*,
> float)
> Aborted (core dumped)
> ===========================
>
> Digging into the source code, I found that the interpolator at line 306 of
> gr_mpsk_receiver_cc.cc return NaN when the inputs are all zeros.
> line 306: gr_complex interp_sample = d_interp->interpolate(&d_dl[d_dl_idx],
> d_mu);
>
> trying it on ubuntu produced no problem.
>
> Is this an known bug?
> Kyle

The error suggests that the d_mu value is < 0, which is unrelated to
the inputs being all 0. There should be no problem with inputs being
all 0, and if d_mu is less than 0, something is going wrong. Not sure
what to tell you right now, but more debug information would be
helpful.

Tom