Argh, OK, I get it: scilab treats A.^2 exactly like A.^%pi and not like "square it". Makes sense, thank you for the info. I wonder how julia is performing with respect to A.^2 compared to A.*A...
Antoine Le Mercredi, Janvier 31, 2018 11:30 CET, Stéphane Mottelet <[email protected]> a écrit: > I am an old school guy and have learned scientific computing with > Fortran... Using mutiplication instead of power elevation is an old > trick which should not be necessary with a more clever interpreter > (which should detect that 2 is actually a (small) integer and use > multiplication instead) > > S. > > Le 31/01/2018 à 11:22, Antoine Monmayrant a écrit : > > Hello Stéphane, > > > > Sorry to hijack the discussion but I didn't know that there was such a > > difference between A.*A and A.^2. > > Could you tell us more about it? > > Why is is twice faster to use the A.*A form? > > Is this documented somewhere? > > > > Cheers, > > > > Antoine > > > > > > Le Mercredi, Janvier 31, 2018 10:53 CET, Stéphane Mottelet > > <[email protected]> a écrit: > > > >> Replacing > >> > >> MinDist=[MinDist sqrt(min(sum(DIFF.^2,2)))]; > >> > >> by > >> > >> MinDist=[MinDist sqrt(min(sum(DIFF.*DIFF,2)))]; > >> > >> will be at least twice faster. Crunching elapsed time could be done by > >> using parallel_run (with 5.5.2 version) if you have a multi-core processor. > >> > >> S. > >> > >> Le 31/01/2018 à 09:36, Dang Ngoc Chan, Christophe a écrit : > >>> Hello, > >>> > >>> The following suggestions will probably not have a drastic influence > >>> (I don't see how it could be more vectorised) > >>> but his a little thing I see: > >>> > >>>> De : users [mailto:[email protected]] De la part de Heinz > >>>> Nabielek > >>>> Envoyé : mercredi 31 janvier 2018 00:13 > >>>> > >>>> MinDist=[MinDist sqrt(min(sum(DIFF.^2,2)))]; > >>> Maybe you could concatenate the squares of the distance > >>> and then compute the square root of the whole vector in the end: > >>> > >>> sqMinDist=[sqMinDist min(sum(DIFF.^2,2))]; > >>> > >>> … > >>> > >>> end > >>> > >>> … > >>> > >>> MinDist = sqrt(sqMinDist) > >>> > >>> Hope this helps, > >>> > >>> Regards > >>> > >>> -- > >>> Christophe Dang Ngoc Chan > >>> Mechanical calculation engineer > >>> This e-mail may contain confidential and/or privileged information. If > >>> you are not the intended recipient (or have received this e-mail in > >>> error), please notify the sender immediately and destroy this e-mail. Any > >>> unauthorized copying, disclosure or distribution of the material in this > >>> e-mail is strictly forbidden. > >>> _______________________________________________ > >>> users mailing list > >>> [email protected] > >>> http://lists.scilab.org/mailman/listinfo/users > >> > >> -- > >> 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 > >> > >> _______________________________________________ > >> users mailing list > >> [email protected] > >> http://lists.scilab.org/mailman/listinfo/users > >> > > _______________________________________________ > > users mailing list > > [email protected] > > http://lists.scilab.org/mailman/listinfo/users > > > -- > 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 > > _______________________________________________ > users mailing list > [email protected] > http://lists.scilab.org/mailman/listinfo/users > _______________________________________________ users mailing list [email protected] http://lists.scilab.org/mailman/listinfo/users
