# Tag Info

## Hot answers tagged tensors

Accepted

### Python's einsum equivalent in Mathematica?

You can implement most of your einsum functionality using TensorContract/TensorTranspose. ...
• 131k
Accepted

• 8,806

### SymmetrizedArray of stiffness/compliance tensor

This is very late to the party, but someone might still be interested. You can do what you want by solving the conditions of the material symmetry group. My answer is organized in 1) Background ...
• 5,513
Accepted

$Assumptions = {(a | b | c) ∈ Vectors[3], g ∈ Reals} TensorReduce[g b.a\[Cross]c - g c.b\[Cross]a] 0 • 399k 9 votes ### Summation of Kronecker deltas should give the dimension You could just do: Sum[KroneckerDelta[μ, ν] KroneckerDelta[μ, ν], {ν, d}, {μ, d}, Assumptions->d>1] d Although it might make sense to use symbolic ... • 131k 9 votes ### How to implement Einstein summation convention with differential operators Let me try to partially answer. Partially for the following reason: I know how to implement index vector and tensor notations and how to work with them. I also wanted to implement the Einstein ... • 39.8k 9 votes ### Array reshaping without explicitly specifying one dimension ArrayReshape doesn't let you do this, but ReshapeLayer does: ... • 24.1k 9 votes ### Doing ArrayReshape in Mathematica doesn't give desired results Try this: Map[Transpose, ArrayReshape[a, {2, 2, 2, 2}]] // MatrixForm Or using Partition: ... • 28.3k 9 votes ### How can I "multiply" nested lists? Distribute[{alist,blist}, List, List,List, Times] (* {{a r, b s, c t}, {a x, b y, c z}, {d r, e s, f t}, {d x, e y, f z}} *) • 20.9k 8 votes ### Higher order SVD I worked on this topic today as I'm interested in it for an interpolation problem. I followed the interlaced computation from the Wikipedia link in the other answers (corresponding paper is here), ... • 11k 8 votes Accepted ### Symbolic calculation with generators and relations Edit. Based on the comments, here is a more concrete answer to what I think you'd like. My previous answer can be found below. Defining a ring symbolically. Let's consider some ring (or algebra) ... • 1,104 8 votes Accepted ### Tensor analysis - Index Notation In Mathematica, symbolic tensors don't necessarily use indices. Instead, tensors are declared to have a certain number of indices (rank): ... • 131k 8 votes Accepted ### Kronecker product$ n \$ matrices

Sequence[ ] would be the go-to, but it flattens out the list. Plan B: You can create a new operator that will 'fold' up the list. Create the operator ...
• 7,193