How to perform vector Matrix Multiplication

13 次查看（过去 30 天）
M Biggs
M Biggs 2018-2-23
回答： James Tursa 2018-2-23
I need to multiply a time series of 4x4 matrices by a corresponding Time series of 4x4 transformation matrices. I am looking for the most efficient method without a for loop.
P_new = T * P
where: P is a nx4x4 matrix, where n is the number of time epochs.
T is a nx4x4 transformation matrix, where n is the number of time steps.
P_new is a nx4x4 version of P that is transformed.
In a loop I would do for i=1:n; P_new(i,1:4,1:4) = T(i,1:4,1:4) * P(i,1:4,1:4); end
How could I do this outside a loop??

请先登录，再回答此问题。

回答（1 个）

James Tursa
James Tursa 2018-2-23
First I would suggest you reorder your dimensions to put the 4x4 matrices first, so that P is 4x4xn and T is 4x4xn. That way all of your 4x4 matrices are contiguous in memory. Then you have some options from the FEX (some of which are mex functions that require a C compiler):
MULTIPROD: https://www.mathworks.com/matlabcentral/fileexchange/8773-multiple-matrix-multiplications--with-array-expansion-enabled
MMX: https://www.mathworks.com/matlabcentral/fileexchange/37515-mmx-multithreaded-matrix-operations-on-n-d-matrices
MTIMESX: https://www.mathworks.com/matlabcentral/fileexchange/25977-mtimesx-fast-matrix-multiply-with-multi-dimensional-support

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by