As a mathematician, I have to correct the subject line to 'Distributive Matrix operations'
-- David -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Doran, Harold Sent: Tuesday, August 14, 2012 12:55 PM To: Berend Hasselman Cc: 'r-help@r-project.org' Subject: Re: [R] Communative Matrix Multiplcation Thanks, Berend. I updated my R and got same result. I reposted the old sessionInfo(), which was an older version. But, same code, same matrices, different result > -----Original Message----- > From: Berend Hasselman [mailto:b...@xs4all.nl] > Sent: Tuesday, August 14, 2012 1:49 PM > To: Doran, Harold > Cc: 'r-help@r-project.org' > Subject: Re: [R] Communative Matrix Multiplcation > > > On 14-08-2012, at 19:26, Doran, Harold wrote: > > > > > I'm not seeing why the following occurs: > > > >> T1 <- (A1 - A2) %*% D > >> T2 <- (A1 %*% D) - (A2 %*% D) > >> identical(T1, T2) > > [1] FALSE > > ....... > > I ran this in a clean environment > > <code> > library(Matrix) > > A1 <- new("dsCMatrix" > , i = c(0L, 1L, 2L, 3L, 0L, 1L, 4L, 2L, 3L, 5L) > , p = c(0L, 1L, 2L, 3L, 4L, 7L, 10L) > , Dim = c(6L, 6L) > , Dimnames = list(NULL, NULL) > , x = c(5, 5, 5, 5, 5, 5, 10, 5, 5, 10) > , uplo = "U" > , factors = list() > ) > > A2 <- new("dgeMatrix" > , x = c(1.41313955042629, 1.23647532592053, 1.36413787785255, > 0.986247245800629, 2.64961487634682, 2.35038512365318, 1.23647532592053, > 1.55872699943971, 0.579347997632991, 1.62544967700677, 2.79520232536024, > 2.20479767463976, 1.36413787785255, 0.579347997632991, 2.75106274522123, > 0.305451379293231, 1.94348587548554, 3.05651412451446, 0.986247245800629, > 1.62544967700677, 0.305451379293232, 2.08285169789937, 2.6116969228074, > 2.3883030771926, 2.64961487634682, 2.79520232536024, 1.94348587548554, > 2.6116969228074, 5.44481720170706, 4.55518279829294, 2.35038512365318, > 2.20479767463976, 3.05651412451446, 2.3883030771926, 4.55518279829294, > 5.44481720170706 > ) > , Dim = c(6L, 6L) > , Dimnames = list(NULL, NULL) > , factors = list() > ) > > D <- new("ddiMatrix" > , diag = "N" > , Dim = c(6L, 6L) > , Dimnames = list(NULL, NULL) > , x = c(5, 5, 5, 5, 10, 10) > ) > > A1 > A2 > D > > T1 <- (A1 - A2) %*% D > T2 <- (A1 %*% D) - (A2 %*% D) > identical(T1, T2) > </code> > > and qot this result > > [1] TRUE > > > so it's now up to you to find out what you did exactly. > > Berend ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. This e-mail and any materials attached hereto, including, without limitation, all content hereof and thereof (collectively, "XR Content") are confidential and proprietary to XR Trading, LLC ("XR") and/or its affiliates, and are protected by intellectual property laws. Without the prior written consent of XR, the XR Content may not (i) be disclosed to any third party or (ii) be reproduced or otherwise used by anyone other than current employees of XR or its affiliates, on behalf of XR or its affiliates. THE XR CONTENT IS PROVIDED AS IS, WITHOUT REPRESENTATIONS OR WARRANTIES OF ANY KIND. TO THE MAXIMUM EXTENT PERMISSIBLE UNDER APPLICABLE LAW, XR HEREBY DISCLAIMS ANY AND ALL WARRANTIES, EXPRESS AND IMPLIED, RELATING TO THE XR CONTENT, AND NEITHER XR NOR ANY OF ITS AFFILIATES SHALL IN ANY EVENT BE LIABLE FOR ANY DAMAGES OF ANY NATURE WHATSOEVER, INCLUDING, BUT NOT LIMITED TO, DIRECT, INDIRECT, CONSEQUENTIAL, SPECIAL AND PUNITIVE DAMAGES, LOSS OF PROFITS AND TRADING LOSSES, RESULTING FROM ANY PERSON'S USE OR RELIANCE UPON, OR INABILITY TO USE, ANY XR CONTENT, EVEN IF XR IS ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR IF SUCH DAMAGES WERE FORESEEABLE. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
