matsbyname (version 0.6.11)

matrixproduct_byname: Name-wise matrix multiplication

Description

Multiplies operands from left to right (when .summarise = FALSE). If .summarise = TRUE, operands are multiplied from first to last.

Usage

matrixproduct_byname(..., .summarise = FALSE)

Value

A matrix representing the name-wise product of operands.

Arguments

...

Operands; constants, matrices, or lists of matrices.

.summarise

When TRUE, a matrix multiplication proceeds down lists of arguments. When FALSE (the default), items are multiplied across lists.

Details

Performs a union and sorting of multiplicand rows and multiplier columns by name prior to multiplication. Zeroes are inserted for missing matrix elements. Doing so ensures that the dimensions of multiplicand and multiplier matrices will be conformable. I.e., the number of columns in multiplicand will equal the number of rows in multiplier, so long as the column names of multiplicand are unique and the row names of multiplier are unique. If column type of the multiplicand is not same as row type of the multiplier on any step of the multiplication, the function will fail. The result is matrix product with row names from the first multiplicand and column names from the last multiplier.

Examples

library(dplyr)
V <- matrix(1:6, ncol = 3, dimnames = list(c("i1", "i2"), c("c1", "c2", "c3"))) %>%
  setrowtype("Industries") %>% setcoltype("Commodities")
G <- matrix(1:4, ncol = 2, dimnames = list(c("c2", "c1"), c("i2", "i1"))) %>%
  setrowtype("Commodities") %>% setcoltype("Industries")
Z <- matrix(11:14, ncol = 2, dimnames = list(c("i1", "i2"), c("s1", "s2"))) %>% 
  setrowtype("Industries") %>% setcoltype("Sectors")
# Succeeds because G is completed to include a row named c3 (that contains zeroes).
matrixproduct_byname(V, G)
if (FALSE) V %*% G # Fails because E lacks a row named c3.
matrixproduct_byname(V, G, Z)
# This also works with lists
matrixproduct_byname(list(V,V), list(G,G))
DF <- data.frame(V = I(list()), G = I(list()))
DF[[1,"V"]] <- V
DF[[2,"V"]] <- V
DF[[1,"G"]] <- G
DF[[2,"G"]] <- G
matrixproduct_byname(DF$V, DF$G)
DF %>% mutate(matprods = matrixproduct_byname(V, G))
# Also works with lists, multiplying down the lists if `.summarise = TRUE`.
matrixproduct_byname(list(V, G, Z), .summarise = TRUE)