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From: johnscpg@googlemail.com
Subject: Re: GNAT vs Matlab - operation on   multidimensional complex matrices
Date: Tue, 24 Mar 2020 08:44:58 -0700 (PDT)
Date: 2020-03-24T08:44:58-07:00	[thread overview]
Message-ID: <0f03ee83-82c5-476c-a154-11c760997ad9@googlegroups.com> (raw)
In-Reply-To: <6c2c0e35-af07-4169-8be5-464ec7fd0fd5@googlegroups.com>


Hi Darek,

Your latest runtimes agree with mine. I ran on a 1 GHz cpu. Your Ryzen 3750H
is iiuc 2.3 GHz. If I divide my runtimes by 2.3 I get pretty much the same
as yours.

The remaining mystery is matlab's sum of the Real array, which matlab runs
in 1/3 the time of the Complex array, even though it does 1/2 as many
operations. I wonder if matlab is running the program on multiple cores.
Here's what www.mathworks.com says:

https://www.mathworks.com/matlabcentral/answers/350324-is-multi-threading-possible-in-matlab

   "Many commands, e.g. sum is multi-threaded internally already: beyond
    a specific data size, the work is distributed to multiple threads,
    which are processed in parallel."

  parent reply	other threads:[~2020-03-24 15:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-23 23:16 GNAT vs Matlab - operation on multidimensional complex matrices darek
2020-03-24  2:07 ` johnscpg
2020-03-24  6:40 ` J-P. Rosen
2020-03-24  9:37 ` Jeffrey R. Carter
2020-03-24 14:55   ` darek
2020-03-24 15:44 ` johnscpg [this message]
2020-03-31 17:25 ` Shark8
2020-03-31 19:20   ` Simon Wright
2020-03-31 19:54     ` Shark8
2020-04-29 21:08     ` vincent.diemunsch
2020-04-01 11:01   ` darek
2020-04-01 15:01     ` J-P. Rosen
2020-04-01 16:39       ` darek
2020-04-01 17:15         ` J-P. Rosen
2020-03-31 20:05 ` Shark8
2020-03-31 20:51   ` Jeffrey R. Carter
2020-06-08 17:42 ` Shark8
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