Quick linear algebra demo

linear algebra in R

# Matrix addition
matrix(c(1, 2, 3, 0, 5, 1), ncol=2) + matrix(c(4, 2, 0, 0.5, 5, 1), ncol=2)

# Matrix multiplication
3 * matrix(c(1, 2, 3, 0, 5, 1), ncol=2)

# Matrix-Vector Multiplication
matrix(c(1, 4, 2, 3, 0, 1), ncol=2) %*% c(1, 5)

# Matrix-Mector Multiplication
matrix(c(1, 2, 3, 0, 5, 1), ncol=2) %*% t(matrix(c(4, 2, 0, 0.5, 5, 1), ncol=2))

# Transpose
t(matrix(c(4, 2, 0, 0.5, 5, 1), ncol=2))

# Inverse
solve(matrix(c(4, 2, 0, 0.5, 5, 1), ncol=2))

# Diagonal matrix * Inverse = Identity
diag(c(1, 2, 3)) * solve(diag(c(1, 2, 3)))