### -----------------------------------------------------------------------
### Autor: Paul Fink, et. al. (Stand: SoSe 2017)
### -----------------------------------------------------------------------


## ----matrix1-------------------------------------------------------------
x <- matrix(nrow = 4, ncol = 2, byrow = TRUE,
            data = c(1, 2, 3, 4, 5, 6, 7, 8))
x

## ----dimensionmatrix-----------------------------------------------------
dim(x)    # Dimension
nrow(x)   # Anzahl Zeilen
ncol(x)   # Anzahl Spalten

## ----lengthmatrix--------------------------------------------------------
length(x) # Laenge des Datenvektors

## ----cbind---------------------------------------------------------------
y <- c(12, 3, 4, 1)
cbind(x, y)
cbind(y, y)

## ----rbind---------------------------------------------------------------
rbind(c(100, 0), x)
rbind(x, x)

## ----einsmatrix----------------------------------------------------------
matrix(nrow = 4, ncol = 2, data = 1)

## ----diagonalmatrix------------------------------------------------------
diag(1, nrow = 2, ncol = 2)

## ----transponieren-------------------------------------------------------
t(x)

## ----matrixmultiplikation------------------------------------------------
y <- matrix(1:6, nrow = 2)
z <- x %*% y
z

## ----kreuzprodukt--------------------------------------------------------
xtx <- crossprod(x)
xtx

## ----matrixvektormultiplikation------------------------------------------
4 * x

## ----matrixnormaladdition------------------------------------------------
t(cbind(c(1,2), y)) + x

## ----matrixzugriff-------------------------------------------------------
z[3,]
z[,2]
z[3:4, -2] # einfacher als z[3:4, c(1,3)]