diagmul: Multiplication of a tensor with a tensor given by its...
In tensorA: Advanced Tensor Arithmetic with Named Indices

Description Usage Arguments Details Value Author(s) See Also Examples

This is a convenience function for scaling elements of a tensor with different numbers based on their position in the tensor.

1	diagmul.tensor(X,i=names(D),D,j=i,by=NULL)

`X`	The tensor to be scaled
`D`	A tensor containing scaling constants
`i`	numeric of character vector giving the dimensions of X to be used for the product.
`j`	numeric of character vector giving the dimensions of D to be used for the product.
`by`	Every operation is parallel for all levels of by in X and/or D.

Let

X_{i_1… i_d k_1 … k_d}

and

D_{j_1… j_d}

than the result is:

E_{i_1… i_d k_1 … k_d}=X_{i_1… i_d k_1 … k_d}D_{j_1… j_d}

A tensor with the shape and dimensions as X with entries X_ik scaled by D_im, where i and k can represent multi-indices.

K. Gerald van den Boogaart

to.tensor

(A <- matrix(rep(1:3,each=3),nrow=3))
(b <- to.tensor(c(1,1/2,1/3)))
diagmul.tensor(as.tensor(A),2,as.tensor(c(1,1/2,1/3)),1)
diagmul.tensor(as.tensor(A),1,as.tensor(c(1,1/2,1/3)),1)
A %*% diag(b)
diag(b) %*% A