Flattens a matrix into a vector in column-major order.

vec(X)

Arguments

X

An Expression or matrix.

Value

An Expression representing the vectorized matrix.

Examples

A <- Variable(2,2)
c <- 1:4
expr <- vec(A)
obj <- Minimize(t(expr) %*% c)
constraints <- list(A == cbind(c(-1,-2), c(3,4)))
prob <- Problem(obj, constraints)
result <- solve(prob)
result$value
#> [1] 20
result$getValue(expr)
#>      [,1]
#> [1,]   -1
#> [2,]   -2
#> [3,]    3
#> [4,]    4