No, not at all actually. I gave small enough matrices so you can eyeball it, but they are way off. It seems to be a problem (ahem, maybe even a bug) with some matrix operations in older version of R.
Newer R yields true for the comparison. > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Nordlund, Dan (DSHS/RDA) > Sent: Tuesday, August 14, 2012 1:57 PM > To: 'r-help@r-project.org' > Subject: Re: [R] Communative Matrix Multiplcation > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > > project.org] On Behalf Of Doran, Harold > > Sent: Tuesday, August 14, 2012 10:27 AM > > To: Doran, Harold; 'r-help@r-project.org' > > Subject: Re: [R] Communative Matrix Multiplcation > > > > Meant to also add > > > > library(Matrix) > > > > for reproducing > > > > From: Doran, Harold > > Sent: Tuesday, August 14, 2012 1:26 PM > > To: r-help@r-project.org > > Subject: Communative Matrix Multiplcation > > > > Friends > > > > I'm not seeing why the following occurs: > > > > > T1 <- (A1 - A2) %*% D > > > T2 <- (A1 %*% D) - (A2 %*% D) > > > identical(T1, T2) > > [1] FALSE > > > > Harold > > > > > dput(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() > > ) > > > dput(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() > > ) > > > dput(D) > > new("ddiMatrix" > > , diag = "N" > > , Dim = c(6L, 6L) > > , Dimnames = list(NULL, NULL) > > , x = c(5, 5, 5, 5, 10, 10) > > ) > > > > Probably FAQ 7.31. Try > > all.equal(T1,T2) > > > Hope this is helpful, > > Dan > > Daniel J. Nordlund > Washington State Department of Social and Health Services Planning, > Performance, and Accountability Research and Data Analysis Division Olympia, > WA 98504-5204 > > > ______________________________________________ > 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. ______________________________________________ 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.
