R Under development (unstable) (2024-02-14 r85901 ucrt) -- "Unsuffered Consequences"
Copyright (C) 2024 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(cpr)
> 
> A <- matrix(1:4, nrow = 10, ncol = 20)
> B <- matrix(1:6, nrow = 10, ncol = 6)
> 
> # verify that passing in one matrix returns that matrix
> x <- tryCatch(build_tensor(A, 1:10), error = function(e) e)
> stopifnot(inherits(x, "error"))
> stopifnot(identical(x$message, "All arguments passed to build_tensor need to be matrices."))
> 
> # verify that passing in one matrix returns that matrix
> tA <- build_tensor(A)
> stopifnot(identical(tA, A))
> 
> # Two ways of building the same tensor product
> tAB  <- build_tensor(A, B)
> tAB2 <- do.call(build_tensor,list(A, B))
> stopifnot(all.equal(tAB, tAB2))
> 
> # direction matters
> tBA <- build_tensor(B, A)
> stopifnot(!isTRUE(all.equal(tBA, tAB)))
> 
> # three and four matrix tensor product
> tABA  <- build_tensor(A, B, A)
> tABAA <- build_tensor(A, B, A, A)
> 
> # verify to established matrices
> rdsAB   <- readRDS("tensorAB.rds")
> rdsBA   <- readRDS("tensorBA.rds")
> rdsABA  <- readRDS("tensorABA.rds")
> rdsABAA <- readRDS("tensorABAA.rds")
> 
> stopifnot(identical(tAB, rdsAB))
> stopifnot(identical(tBA, rdsBA))
> stopifnot(identical(tABA, rdsABA))
> stopifnot(identical(tABAA, rdsABAA))
> 
> 
> ################################################################################
> #                                 End of File                                  #
> ################################################################################
> 
> proc.time()
   user  system elapsed 
   0.25    0.09    0.34