Matrices Flashcards
1
Q
t(x)
A
transpose
2
Q
diag(x)
A
diagonal
3
Q
%*%
A
matrix multiplication
4
Q
solve(a,b)
A
solves a %*% x = b for x
5
Q
solve(a)
A
matrix inverse of a
6
Q
rowsum(x)
A
sum of rows for a matrix-like object; rowSums(x) is a faster
version
7
Q
colsum(x), colSums(x)
A
sum of columns for a matrix-like object; colSums(x) is a faster
version
8
Q
rowMeans(x)
A
fast version of row means
9
Q
colMeans(x)
A
fast version of col means
