search for: malmig

Displaying 4 results from an estimated 4 matches for "malmig".

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2005 Aug 17
2
power of a matrix
Dear all, I have a population with three age-classes, at time t=0 the population is: n.zero <- c(1,0,0) I have a transition matrix A which denotes "fertility" and "survival": A <- matrix(c(0,1,5, 0.3,0,0, 0,0.5,0), ncol=3, byrow=TRUE) To obtain the population at t=1, I calculate: A %*% n.zero To obtain the population t=2, I calculate: A %*% (A %*% n.zero) ... and so
2007 May 06
7
A function for raising a matrix to a power?
Hi, Is there a function for raising a matrix to a power? For example if you like to compute A%*%A%*%A, is there an abbreviation similar to A^3? Atte Tenkanen > A=rbind(c(1,1),c(-1,-2)) > A [,1] [,2] [1,] 1 1 [2,] -1 -2 > A^3 [,1] [,2] [1,] 1 1 [2,] -1 -8 But: > A%*%A%*%A [,1] [,2] [1,] 1 2 [2,] -2 -5
2005 Jun 08
2
CRAN task view for genetics
Hello to everyone! I have built CRAN task view for genetics. For now I have not submit it to CRAN yet and it can be accessible from: http://www.bfro.uni-lj.si/MR/ggorjan/software/R/Genetics.html http://www.bfro.uni-lj.si/MR/ggorjan/software/R/Genetics.ctv I have not submitted it to CRAN, since I would like first some opinion about it.
2005 Jun 29
6
x*x*x*... vs x^n
Hi I have been wondering if there one can speed up calculating small powers of numbers such as x^8 using multiplication. In addition, one can be a bit clever and calculate x^8 using only 3 multiplies. look at this: > f1 <- function(x){x*x*x*x*x*x*x*x} > f2 <- function(x){x^8} > f3 <- function(x){x2 <- x*x;x4 <- x2*x2;return(x4*x4)} [so f1() and f2() and f3() are