Product between a Filebacked Big Matrix and a vector.

big_prodVec(
  X,
  y.col,
  ind.row = rows_along(X),
  ind.col = cols_along(X),
  center = NULL,
  scale = NULL
)

Arguments

X

An object of class FBM.

y.col

A vector of same size as ind.col.

ind.row

An optional vector of the row indices that are used. If not specified, all rows are used. Don't use negative indices.

ind.col

An optional vector of the column indices that are used. If not specified, all columns are used. Don't use negative indices.

center

Vector of same length of ind.col to subtract from columns of X.

scale

Vector of same length of ind.col to divide from columns of X.

Value

\(X \cdot y\).

Examples

X <- big_attachExtdata() n <- nrow(X) m <- ncol(X) y <- rnorm(m) test <- big_prodVec(X, y) # vector true <- X[] %*% y # one-column matrix all.equal(test, as.numeric(true))
#> [1] TRUE
# subsetting ind.row <- sample(n, n/2) ind.col <- sample(m, m/2) tryCatch(test2 <- big_prodVec(X, y, ind.row, ind.col), error = function(e) print(e))
#> <simpleError: Incompatibility between dimensions.>
# returns an error. You need to use the subset of y: test2 <- big_prodVec(X, y[ind.col], ind.row, ind.col) true2 <- X[ind.row, ind.col] %*% y[ind.col] all.equal(test2, as.numeric(true2))
#> [1] TRUE