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lwa-project / ng_digital_processor

The Next Generation Digital Processor for LWA North Arm
Apache License 2.0
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T-engine output is all zeros #14

Closed jaycedowell closed 1 year ago

jaycedowell commented 1 year ago

Everything is zero coming into ReChannelizerOp. Capture looks ok-ish at ~5% packet loss. Zeros in is zeros out.

jaycedowell commented 1 year ago

Looking at what BeamformerOp writes to its output ring it looks like there is a beam numbering problem somewhere. A beam command for beam 1 is translated to beam 0 (somewhere) and the beam comes out in the wrong place. Is this in the control software?

jaycedowell commented 1 year ago

Is this in the control software?

Yes - https://github.com/lwa-project/ng_digital_processor/blob/sevilleta_based/scripts/ndp/Ndp.py#L227

This also seems to happen with DRX commands but they have zero-based beam indexing to start with. Maybe the correct thing to do is update ndp_drx.py so that it expects zero-based beam indexing?

jaycedowell commented 1 year ago

After c7ba513 it looks like we still have zeros, now at the output of ReChannelizerOp.

jaycedowell commented 1 year ago

This problem with ReChannelizerOp could be related to a seg fault I get when I try to bifrost.memory.memset the internal data buffer to zero. I had commented that out at some point but maybe that needs to be solved first.

jaycedowell commented 1 year ago

Replaced the bifrost.memory.memset call with a bifrost.ndarray.memset_array call. That helps but does point out a problem with how bifrost.memory.memset in implemented. It seems to rely on ndarray.flags for space information that isn't there.

jaycedowell commented 1 year ago

Tracked this down to a bifrost.fft problem that I hadn't completely patched (see https://github.com/ledatelescope/bifrost/issues/202). Now non-zero data comes out of the T-engine at least for the non-PFB inverter case. I'll keep this open until I test with the inverter turned on.

jaycedowell commented 1 year ago

The inverter doesn't appear to be inverting correctly but the data are non-zero.