Bug 2464 – Store spectrum conversion matrix in CSR format

Bug 2464 - Store spectrum conversion matrix in CSR format


Summary:	Store spectrum conversion matrix in CSR format

Status:	RESOLVED FIXED

Product:	ns-3
Classification:	Unclassified
Component:	spectrum
Version:	ns-3-dev
Hardware:	All All

Importance:	P5 enhancement
Assigned To:	Nicola Baldo

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2016-08-06 19:06 UTC by Alexander Krotov
Modified:	2016-10-19 09:00 UTC (History)
CC List:	1 user (show)

See Also:

Attachments
Proposed patch (3.52 KB, patch) 2016-08-06 19:06 UTC, Alexander Krotov	Details \| Diff
Benchmark scenario (2.60 KB, text/x-c++src) 2016-08-06 21:18 UTC, Alexander Krotov	Details
Proposed patch (3.53 KB, patch) 2016-10-16 19:08 UTC, Alexander Krotov	Details \| Diff
Show Obsolete (1) Add an attachment (proposed patch, testcase, etc.)

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Description Alexander Krotov 2016-08-06 19:06:24 UTC

Created attachment 2518 [details]
Proposed patch

Spectrum conversion matrix is usually sparse. In most cases bands of TX and RX correspond one-to-one, so the matrix is diagonal even. So I decided that matrix should be stored in CSR format instead of vector of vectors.

Proposed patch is attached.

Comment 1 Alexander Krotov 2016-08-06 20:18:02 UTC

I checked that patch results in much less multiplications, but the improvement in time is not that great. Probably it needs more benchmarking in large scenarios and feedback.

Comment 2 Alexander Krotov 2016-08-06 21:18:30 UTC

Created attachment 2524 [details]
Benchmark scenario

For attached scenario proposed patch shows about 30% reduction in time on my computer (from ~30 seconds to ~20 seconds).

Comment 3 Nicola Baldo 2016-10-16 17:47:48 UTC

Hi Alex,

thanks a lot for this patch, it looks very good! I think it would be very nice to include it. The only (minor) comment I have is to change operator [] to .at() for accessing std::vector elements. Other than this, the implementation looks very neat! Please go ahead and push it.

Comment 4 Alexander Krotov 2016-10-16 19:08:44 UTC

Created attachment 2620 [details]
Proposed patch

I have updated patch to use at() and tested it.

I can't push it as I have no write access to ns-3-dev.

Comment 5 Alexander Krotov 2016-10-19 09:00:27 UTC

Pushed in changeset 608e628ef4b5