Given matrices `x`

and `y`

as arguments, return a matrix
cross-product.
This is formally equivalent to (but usually slightly faster than) the call `t(x) %*% y`

(tcrossprod) or `x %*% t(y)`

(tcrossprod).

1 2 3 4 5 | ```
tcrossprod(x, y)
## S4 method for signature 'dgeMatrix'
tcrossprod(x, y)
## S4 method for signature 'dtrMatrix'
tcrossprod(x, y)
``` |

`x` |
dense matrix or vector represented as a single row matrix. |

`y` |
dense matrix or vector represented as single row matrix. |

For further details on classes and methods see the full Matrix package documentation.

- tcrossprod
`(signature(x = "dgeMatrix", y = "missing")`

: Calls CUBLAS function`cublasDsyrk`

for GPU enabled systems and`PLASMA_dsyrk`

for multi-core systems. Library settings also affect choice between GPU and CPU. If`y = NULL`

, then it is taken to be the same matrix as`x`

.- tcrossprod
`(signature(x = "dgeMatrix", y = "dgeMatrix")`

: Calls MAGMA function`magma_dgemm`

for GPU enabled systems and`PLASMA_dgemm`

for multi-core systems. Library settings also affect choice between GPU and CPU.- tcrossprod
`(signature(x = "dgeMatrix", y = "Matrix")`

: Calls MAGMA function`magma_dgemm`

for GPU enabled systems and`PLASMA_dgemm`

for multi-core systems. Library settings also affect choice between GPU and CPU.- tcrossprod
`(signature(x = "dgeMatrix", y = "numeric")`

: Calls MAGMA function`magma_dgemm`

for GPU enabled systems and`PLASMA_dgemm`

for multi-core systems. Library settings also affect choice between GPU and CPU.`y`

is coerced to a`base::matrix`

.- tcrossprod
`(signature(x = "dgeMatrix", y = "matrix")`

: Calls MAGMA function`magma_dgemm`

for GPU enabled systems and`PLASMA_dgemm`

for multi-core systems. Library settings also affect choice between GPU and CPU.- tcrossprod
`(signature(x = "dtrMatrix", y = "dtrMatrix")`

: Calls CUBLAS function`cublasDtrmm`

for GPU enabled systems and`PLASMA_dtrmm`

for multi-core systems. Library settings also affect choice between GPU and CPU.- tcrossprod
`(signature(x = "denseMatrix", y = "dtrMatrix")`

:`y`

inherits from virtual class`ddenseMatrix`

Calls MAGMA function`magma_dgemm`

for GPU enabled systems and`PLASMA_dgemm`

for multi-core systems. Library settings also affect choice between GPU and CPU.- tcrossprod
`(signature(x = "matrix", y = "dtrMatrix")`

: Calls CUBLAS function`cublasDtrmm`

for GPU enabled systems and`PLASMA_dtrmm`

for multi-core systems. Library settings also affect choice between GPU and CPU.

Martin Maechler, Douglas Bates (Matrix package)

1 2 3 4 5 6 7 8 9 10 11 12 | ```
m <- matrix(0, 400, 500)
set.seed(12)
m[runif(314, 0, length(m))] <- 1
mm <- as(m, "dgeMatrix")
object.size(m) / object.size(mm) # smaller by a factor of > 200
## tcrossprod() is very fast:
system.time(tCmm <- tcrossprod(mm))
system.time(cm <- crossprod(t(m)))
system.time(cm. <- tcrossprod(m))
stopifnot(cm == as(tCmm, "matrix"))
``` |

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