How to code this mathematical (tensor) formula in Matlab

Question

Tyler 2015-11-28

回答： Walter Roberson 2015-11-29

Hi, i'm looking to code this tensor notation formula into matlab:

X = e.n - [n.e.n]n

where n is a unit vector, e is a 3x3 tensor (strain), and "." represents a dot product.

My initial code is the following:

X = e_tensor*n - n*transpose(e_tensor*n)*n

However, i am not able to recreate the results of the paper i am reading.

Is it possible my matlab code doesnt correctly represent the tensor formula?

Any help would be greatly appreciated.

Thanks,

Tyler

Answer 1

Walter Roberson 2015-11-29

"*" is not the dot product.

X = dot(e_tensor, n) - dot(n, transpose( dot(e_tensor, n) )) * n

However, I do not see where the transpose is coming from, and the meaning of [something]n is not described.

Also, your e_tensor is 3 x 3 and your n is a unit vector. The MATLAB dot product is only defined between arrays (or vectors) that are the same size.