Extracting matrix from a matrix

Extracting matrix from a matrix - Extract a matrix from an existing matrix - "slicing" - Messages

#21 Posted: 9/10/2016 8:34:35 AM
Radovan Omorjan

Radovan Omorjan

325 likes in 2052 posts.

Group: Moderator

Although I am very satisfied with this feature, I have to agree with Martin. It might be a bit confusing this way, because the row-wise indexing for matrices as indexes is more expected than column-wise.

Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
#22 Posted: 9/10/2016 8:59:51 AM
frapuano

frapuano

13 likes in 115 posts.

Group: User

..Probably I ma stupid but I haven't clearly understood the syntax of the command and how to use it ( ..and so the Andrey's examples) .

If there is someone that can take a moment to explain this , it would be very appreciated

Best regards

Franco
#23 Posted: 9/10/2016 9:24:19 AM
Radovan Omorjan

Radovan Omorjan

325 likes in 2052 posts.

Group: Moderator

Hello Franco,

Just play with this a bit, and you will figure out

Extract Matrix with matrix indices

Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
3 users liked this post
francesco rapuano 1/26/2025 1:34:00 AM, frapuano 9/10/2016 9:32:00 AM, Andrey Ivashov 9/10/2016 12:07:00 PM
#24 Posted: 9/10/2016 11:51:19 AM
Jean Giraud

Jean Giraud

983 likes in 6866 posts.

Group: User

Wrote

I hoped this might be the most simplest way.



Not so easy ! At the machine code, everything is linear.
That's what the "ct" counter does system wise, then returned
math style. Just a bit more about Delta matrix. The JPG
explanation is short, just the principle of it. There is lot
more behind the scene.

Jean

Matrix Delta.gif

Utilities Matrix Mirror QUICK.sm (17 KiB) downloaded 52 time(s).



1 users liked this post
Radovan Omorjan 9/10/2016 1:28:00 PM
#25 Posted: 9/19/2016 6:59:53 PM
Andrey Ivashov

Andrey Ivashov

2269 likes in 3729 posts.

Group: Super Administrator

Wrote

The sandbox example shows the use of matrices as indices. The question is, how the rules for such indices are.

A straightforward rule would be that whatever you provide as index structure, it is accessed by linear indexing from 1..length() of the index structure.

The following example shows that the actual behaviour is different. The index matrices are indexed column-wise and not row-wise as the usual linear indexing works.

I propose to change this in order to be consistent with general linear indexing.


Thank you! Fixed by Davide.

Best regards.
2 users liked this post
Radovan Omorjan 9/20/2016 2:10:00 AM, frapuano 9/20/2016 4:25:00 AM
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