tidymatrix.R

as_tidymatrix <- function(x){
  structure(list(.value = as.vector(x),
                 .row = as.vector(row(x)),
                 .col = as.vector(col(x))),
            row.names = seq_len(length(as.vector(x))),
            nrow = nrow(x), # need these attribute if storing it as sparse later
            ncol = ncol(x),
            class = c("tidymatrix", "data.frame"))
}

as.matrix.tidymatrix <- function(x) {
  matrix(data = x$.value, 
         nrow = attr(x, "nrow"), 
         ncol = attr(x, "ncol"))
}

`%*%.tidymatrix` <- function(x, y) {
  res <- as.matrix(x) %*% as.matrix(y)
  as_tidymatrix(res)
}

x <- as_tidymatrix(matrix(1:6, nrow = 2))
y <- as_tidymatrix(matrix(1:9, nrow = 3))
x %*% y
# error -> Primitive("%*%") has some check built-in :(
# requires numeric/complex matrix/vector arguments

`+.tidymatrix` <- function(x, y) {
  res <- as.matrix(x) + as.matrix(y)
  as_tidymatrix(res)
}

z <- as_tidymatrix(matrix(1, nrow = 3, ncol = 3))
y + z

This works. Thanks Brenton Wiernik for the info.

`%*%` <- function(x, y) {
  UseMethod("%*%")
}

`%*%.matrix` <- function(x, y) {
  .Primitive("%*%")(x, y)
}

`%*%.tidymatrix` <- function(x, y) {
  res <- as.matrix(x) %*% as.matrix(y)
  as_tidymatrix(res)
}

x <- as_tidymatrix(matrix(1:6, nrow = 2))
y <- as_tidymatrix(matrix(1:9, nrow = 3))
x %*% y