[Scilab-users] [EXTERNAL] Re: feedback on removing 1 row and 1 column

[Stéphane Mottelet]

Hello Paul,

A fix is under review for master at 
https://codereview.scilab.org/#/c/20965/, I hope it will be reviewed and 
merged soon (timings are done on my machine, an old mid-2010 MacPro) :

--> MAT=rand(2.3e6,6);
--> tic;MAT(:,$)=[];toc
  ans  =

    0.051402

--> MAT=rand(2.3e6,6);
--> tic;MAT(:,[1 3])=[];toc
ans  =

    0.046928

S.

Le 30/04/2019 à 14:04, Carrico, Paul a écrit :
>
> Thanks all
>
> Indeed, getting the complete block works fine and it’s instantaneous
>
> Paul
>
> *De :*users [mailto:users-bounces at lists.scilab.org] *De la part de* 
> Stéphane Mottelet
> *Envoyé :* mardi 30 avril 2019 12:41
> *À :* users at lists.scilab.org
> *Objet :* [EXTERNAL] Re: [Scilab-users] feedback on removing 1 row and 
> 1 column
>
> Le 30/04/2019 à 08:44, Carrico, Paul a écrit :
>
>     Dear All
>
>     I’ve been using successfully Scilab for years, to develop my
>     projects; I do not remember if I’ve ever had to deal with huge
>     matrixes but that’s the case today.
>
>     Using “csvRead”, I got a matrix with 2.3 million of rows and 6
>     columns (it took about 240 seconds to read it J); nevertheless
>     I’ve been surprised when I tried to remove the first row and the
>     last column using basically:
>
>     MAT(1,:) = []; MAT(:,$) = [];
>
> in the meantime (before we fix this), you can do
>
> MAT = MAT(:,1:$-1);
>
> which will be way faster !
>
> S.
>
>     Indeed I needed to kill the process after about 10 minutes (same
>     result both under Windows 10 and Linux – RAM not fully used).
>
>     By comparison, the same process is instantaneous under Python
>     using Numpy (numpy.delete) using of course the same matrix.
>
>     A feedback I wanted to share ….
>
>     PaulEXPORT CONTROL :
>
>     « Cet email ne contient pas de données techniques »
>
>     « This email does not contain technical data »
>
>
>
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> -- 
> Stéphane Mottelet
> Ingénieur de recherche
> EA 4297 Transformations Intégrées de la Matière Renouvelable
> Département Génie des Procédés Industriels
> Sorbonne Universités - Université de Technologie de Compiègne
> CS 60319, 60203 Compiègne cedex
> Tel : +33(0)344234688
> http://www.utc.fr/~mottelet  <https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/urldefense.proofpoint.com/v2/url?u=http-3A__www.utc.fr_-7Emottelet&d=DwMD-g&c=0hKVUfnuoBozYN8UvxPA-w&r=2R_Eyw3woK4XVPnEug_8oZFQfCE8Ul6UYufxQizYx6k&m=8u_kv9vrBYRsyNeOuOx1-8PC4J3mnOk3lTxHZb9M1Ag&s=lgW8LxCQDNlDkDXz_laFa3r_BQoToZw3IAT2XDiJNf0&e=>
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-- 
Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
http://www.utc.fr/~mottelet

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