As far as I can tell, R doesn’t have a function for building block diagonal matrices so as I needed one, I’ve coded it myself. It might save someone some time. Example: Let m1 and m2 two square matrices. Selec … Continue reading →
Posts Tagged ‘ matrix ’
Hierarchial Cluster Analysis
With the distance matrix found in previous tutorial, we can use various techniques of cluster analysis for relationship discovery. For example, for the data set mtcars, we can use the hclust method with the distance matrix and plot a dendrogram that ...
Example 7.31: Contour plot of BMI by weight and height
A contour plot is a simple way to plot a surface in two dimensions. Lines with a constant Z value are plotted on the X-Y plane.Typical uses include weather maps displaying "isobars" (lines of constant pressure), and maps displaying lines of constant e...
Sorting a matrix/data.frame on a column
mat.sort <- function(mat,n) { mat),] <- mat return(mat) } a <- matrix(rnorm(100),ncol=10) mat.sort(a,1)
R matrices in C functions
Using the .C() function in R, you can only pass vectors. Since R stores matrices columnwise as vectors anyhow, they can be passed to your C function as vectors (along with the number of rows in the matrix) and then accessed in familiar manner...
Repeat elements of a vector
Two methods. The first produces a vector, the second a one column matrix.x=1:10# Method 1rep(x,each=3)# Method 2matrix(t(matrix(x,length(x),3)))
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
