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## Re: Order of matrix multiplication

**From**: |
siko1056 |

**Subject**: |
Re: Order of matrix multiplication |

**Date**: |
Tue, 13 Sep 2016 01:36:59 -0700 (PDT) |

Mike Miller-4 wrote
>* Agreed. IMHO mtimes and the * operator would retain the expected*
>* left-associativity property, but another function could be introduced*
>* that determines a different order to perform pairwise multiplications*
>* for performance.*
I think many Octave users know from courses about linear algebra, that the
order of operations matters (e.g. painful pen&paper computation of outer
product times vector w'*w*x or w'*(w*x)) and are able to identify such
inappropriate operation order, like in the initial example.
I agree that Octave can have linter integrated inside the editor (like with
Matlab's checkcode function) to suggest such and many other optimizations
(vectorizing statements, ...). But I would not like to apply optimizations
by default. Maybe some teaching person likes to visualize this effect, or
simply relies on the order of operations.
Kai
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**Order of matrix multiplication**, *Bernardo Sulzbach*, `2016/09/12`
**Re: Order of matrix multiplication**, *Nicholas Jankowski*, `2016/09/12`
**Re: Order of matrix multiplication**, *Nicholas Jankowski*, `2016/09/12`
**Re: Order of matrix multiplication**, *Yu Liu*, `2016/09/12`
**Re: Order of matrix multiplication**, *Nicholas Jankowski*, `2016/09/12`
**Re: Order of matrix multiplication**, *Bernardo Sulzbach*, `2016/09/12`
**Re: Order of matrix multiplication**, *Nicholas Jankowski*, `2016/09/12`
**Re: Order of matrix multiplication**, *Mike Miller*, `2016/09/12`
**Re: Order of matrix multiplication**, *Bernardo Sulzbach*, `2016/09/12`
**Re: Order of matrix multiplication**,
*siko1056* **<=**
**Re: Order of matrix multiplication**, *Bernardo Sulzbach*, `2016/09/13`