More type deductions for matrix multiplication

[Dirk Schumacher]

mat %*% colvec = colvec
rowvec %*% mat = rowvec
mat %*% mat = mat
T %*% <scalar> = T
<scalar> %*% T = T

[Dirk Schumacher]

The relevant code is here:

armacmp/R/ast-classes.R

Lines 830 to 858 in 5777a3f

 get_cpp_type = function() { 
   arma_type <- find_arma_cpp_types(self$get_tail_elements()) 
   arma_cpp_types <- vapply(arma_type, function(x) x$get_cpp_type(), character(1L)) 
   if (length(arma_type) == 2L) { 
     is_integer_arma_type <- function(type) { 
       grepl("^arma::i", type) 
     } 
     is_unsigned_integer_arma_type <- function(type) { 
       grepl("^arma::u", type) 
     } 
     is_double_arma_type <- function(type) { 
       type %in% paste0("arma::", c("vec", "colvec", "rowvec", "mat")) 
     } 
     # TODO: revisit these rules and contemplate 
     if (any(sapply(arma_cpp_types, is_double_arma_type))) { 
       return("arma::mat") 
     } 
     if (any(sapply(arma_cpp_types, is_integer_arma_type))) { 
       return("arma::imat") 
     } 
     if (all(sapply(arma_cpp_types, is_unsigned_integer_arma_type))) { 
       return("arma::umat") 
     } 
   } 
   if (length(arma_type) == 1L) { 
     return(arma_type[[1L]]$get_cpp_type()) 
   } 
   "arma::mat" 
 } 

[Dirk Schumacher]

There is also a lot of room for refactoring and making this stuff smarter :)