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Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.]
From: |
Martin Helm |
Subject: |
Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.] |
Date: |
Mon, 20 Feb 2012 11:13:47 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.2) Gecko/20120215 Thunderbird/10.0.2 |
Am 20.02.2012 11:04, schrieb Tatsuro MATSUOKA:
> Hello
>
> Please tell me which is correct to measure the performance.
>
> 1. n=2000; A=randn(n); B=randn(n);tic; C=A*B; t=toc, MFLOPS=2*n^3/t*1e-6
>
> 2. n=2000; A=randn(n); B=randn(n);ta=cputime; C=A*B; t=cputime-ta,
> MFLOPS=2*n^3/t*1e-6
>
> Case 1 gives two - four times faster than that of the case 2.
>
> Example
> octave:2> n=2000; A=randn(n); B=randn(n);tic; C=A*B; t=toc,
> MFLOPS=2*n^3/t*1e-6
> t = 0.70904
> MFLOPS = 2.2566e+004
> octave:3> n=2000; A=randn(n); B=randn(n);ta=cputime; C=A*B; t=cputime-ta,
> MFLOPS=2*n^3/t*1e-6
> t = 1.4040
> MFLOPS = 1.1396e+004
>
>
> Which test is correct to check the performance.
>
> Regards
>
> Tatsuro
>
The cputime sums together the time spent on all cpu's so if it runs lets
say a total of 4sec till its complete parallel on 4 cpu's then cputime
will give 16sec.
You better use tic/toc.
- Re: Octave 3.6.0 on Windows XP plot fails., (continued)
- Re: Octave 3.6.0 on Windows XP plot fails., Philip Nienhuis, 2012/02/17
- Re: Octave 3.6.0 on Windows XP plot fails., Michael Goffioul, 2012/02/17
- Re: Octave 3.6.0 on Windows XP plot fails., nitnit, 2012/02/18
- MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Philip Nienhuis, 2012/02/19
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], nitnit, 2012/02/19
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Xianyi Zhang, 2012/02/19
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], nitnit, 2012/02/20
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Tatsuro MATSUOKA, 2012/02/20
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Tatsuro MATSUOKA, 2012/02/20
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Xianyi Zhang, 2012/02/20
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.],
Martin Helm <=
- Re: MinGW libblas [WAS: Re: Octave 3.6.0 on Windows XP plot fails.], Tatsuro MATSUOKA, 2012/02/20
- Re: Octave 3.6.0 on Windows XP plot fails., Tatsuro MATSUOKA, 2012/02/21
- Re: Octave 3.6.0 on Windows XP plot fails., nitnit, 2012/02/21
- Re: Octave 3.6.0 on Windows XP plot fails., PhilipNienhuis, 2012/02/23
- Re: Octave 3.6.0 on Windows XP plot fails., Xianyi Zhang, 2012/02/25
- Re: Octave 3.6.0 on Windows XP plot fails., nitnit, 2012/02/25
- Re: Octave 3.6.0 on Windows XP plot fails., Xianyi Zhang, 2012/02/26
- Re: Octave 3.6.0 on Windows XP plot fails., maiky76, 2012/02/26
- Re: Octave 3.6.0 on Windows XP plot fails., Xianyi Zhang, 2012/02/27
- Re: Octave 3.6.0 on Windows XP plot fails., nitnit, 2012/02/27