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3

$begingroup$

Is there a more elegant way of dealing with the following subscripting?

Do[threetest = 
MatrixRank[threepoints[[i]][[2]][[1]] - 
threepoints[[i]][[1]][[1]], 
threepoints[[i]][[2]][[2]] - threepoints[[i]][[1]][[2]],
threepoints[[i]][[3]][[1]] - threepoints[[i]][[1]][[1]],
threepoints[[i]][[3]][[2]] - threepoints[[i]][[1]][[2]]]; 
If[threetest < 2, Break[], 1], i, Binomial[n, 3]]

matrix notation

share|improve this question

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

$endgroup$

closed as off-topic by Roman, Henrik Schumacher, m_goldberg, happy fish, Alex Trounev Apr 27 at 12:25

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – Roman, Henrik Schumacher, m_goldberg, happy fish, Alex Trounev

If this question can be reworded to fit the rules in the help center, please edit the question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  If the last dimension of threePoints is two, then you might try something like MatrixRank[threepoints[[i, 2 ;; 3]] - threepoints[[i, 1]]].
  $endgroup$
  – WReach
  Apr 26 at 18:29
  

  
  
  
  

add a comment | 

3

$begingroup$

Is there a more elegant way of dealing with the following subscripting?

Do[threetest = 
MatrixRank[threepoints[[i]][[2]][[1]] - 
threepoints[[i]][[1]][[1]], 
threepoints[[i]][[2]][[2]] - threepoints[[i]][[1]][[2]],
threepoints[[i]][[3]][[1]] - threepoints[[i]][[1]][[1]],
threepoints[[i]][[3]][[2]] - threepoints[[i]][[1]][[2]]]; 
If[threetest < 2, Break[], 1], i, Binomial[n, 3]]

matrix notation

share|improve this question

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

$endgroup$

closed as off-topic by Roman, Henrik Schumacher, m_goldberg, happy fish, Alex Trounev Apr 27 at 12:25

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – Roman, Henrik Schumacher, m_goldberg, happy fish, Alex Trounev

If this question can be reworded to fit the rules in the help center, please edit the question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  If the last dimension of threePoints is two, then you might try something like MatrixRank[threepoints[[i, 2 ;; 3]] - threepoints[[i, 1]]].
  $endgroup$
  – WReach
  Apr 26 at 18:29
  

  
  
  
  

add a comment | 

$begingroup$

Is there a more elegant way of dealing with the following subscripting?

Do[threetest = 
MatrixRank[threepoints[[i]][[2]][[1]] - 
threepoints[[i]][[1]][[1]], 
threepoints[[i]][[2]][[2]] - threepoints[[i]][[1]][[2]],
threepoints[[i]][[3]][[1]] - threepoints[[i]][[1]][[1]],
threepoints[[i]][[3]][[2]] - threepoints[[i]][[1]][[2]]]; 
If[threetest < 2, Break[], 1], i, Binomial[n, 3]]

matrix notation

share|improve this question

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

$endgroup$

Do[threetest = 
MatrixRank[threepoints[[i]][[2]][[1]] - 
threepoints[[i]][[1]][[1]], 
threepoints[[i]][[2]][[2]] - threepoints[[i]][[1]][[2]],
threepoints[[i]][[3]][[1]] - threepoints[[i]][[1]][[1]],
threepoints[[i]][[3]][[2]] - threepoints[[i]][[1]][[2]]]; 
If[threetest < 2, Break[], 1], i, Binomial[n, 3]]

share|improve this question

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

share|improve this question

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

edited Apr 26 at 17:48

user64494

3,65111222

edited Apr 26 at 17:48

user64494

3,65111222

asked Apr 26 at 15:29

user94858user94858

161

asked Apr 26 at 15:29

user94858user94858

161

2 Answers
2

active

oldest

votes

10

$begingroup$

If threepoints is defined with any kind of regularity, then threepoints[[i]][[2]][[1]] is the same as threepoints[[i,2,1]]. See the documentation of Part.

Further, you can do vector processing with ;;, along the lines of

Do[threetest = 
 MatrixRank[threepoints[[i, 2, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]], 
 threepoints[[i, 3, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

If the third coordinate of threetest has only two slots (that is, if Dimensions[threetest] returns something,something,2), then the above can also be written as

Do[threetest = 
 MatrixRank[threepoints[[i, 2]] - threepoints[[i, 1]], 
 threepoints[[i, 3]] - threepoints[[i, 1]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

share|improve this answer

edited Apr 26 at 18:50

answered Apr 26 at 15:33

RomanRoman

7,14511134

$endgroup$

add a comment | 

6

$begingroup$

The other thing I do is to use the stylized brackets in all of my MMA code. Stackexchange mangles it, so have to use a picture to demonstrate:

Big difference in readability.

share|improve this answer

answered Apr 26 at 18:04

MikeYMikeY

3,903916

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Also, you can put them in the subscript and they work equally. And if it's still not enough, you can use the invisible comma to separate indices. ;-)
  $endgroup$
  – Veky
  Apr 27 at 3:53
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  It’s probably worth adding how to enter these doubled brackets using the keyboard: Esc–[–[–Esc.
  $endgroup$
  – Stephen Powell
  Apr 27 at 9:17
  

  
  
  
  

add a comment | 

10

$begingroup$

If threepoints is defined with any kind of regularity, then threepoints[[i]][[2]][[1]] is the same as threepoints[[i,2,1]]. See the documentation of Part.

Further, you can do vector processing with ;;, along the lines of

Do[threetest = 
 MatrixRank[threepoints[[i, 2, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]], 
 threepoints[[i, 3, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

If the third coordinate of threetest has only two slots (that is, if Dimensions[threetest] returns something,something,2), then the above can also be written as

Do[threetest = 
 MatrixRank[threepoints[[i, 2]] - threepoints[[i, 1]], 
 threepoints[[i, 3]] - threepoints[[i, 1]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

share|improve this answer

edited Apr 26 at 18:50

answered Apr 26 at 15:33

RomanRoman

7,14511134

$endgroup$

add a comment | 

10

$begingroup$

If threepoints is defined with any kind of regularity, then threepoints[[i]][[2]][[1]] is the same as threepoints[[i,2,1]]. See the documentation of Part.

Further, you can do vector processing with ;;, along the lines of

Do[threetest = 
 MatrixRank[threepoints[[i, 2, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]], 
 threepoints[[i, 3, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

If the third coordinate of threetest has only two slots (that is, if Dimensions[threetest] returns something,something,2), then the above can also be written as

Do[threetest = 
 MatrixRank[threepoints[[i, 2]] - threepoints[[i, 1]], 
 threepoints[[i, 3]] - threepoints[[i, 1]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

share|improve this answer

edited Apr 26 at 18:50

answered Apr 26 at 15:33

RomanRoman

7,14511134

$endgroup$

add a comment | 

$begingroup$

If threepoints is defined with any kind of regularity, then threepoints[[i]][[2]][[1]] is the same as threepoints[[i,2,1]]. See the documentation of Part.

Further, you can do vector processing with ;;, along the lines of

Do[threetest = 
 MatrixRank[threepoints[[i, 2, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]], 
 threepoints[[i, 3, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

If the third coordinate of threetest has only two slots (that is, if Dimensions[threetest] returns something,something,2), then the above can also be written as

Do[threetest = 
 MatrixRank[threepoints[[i, 2]] - threepoints[[i, 1]], 
 threepoints[[i, 3]] - threepoints[[i, 1]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

share|improve this answer

edited Apr 26 at 18:50

answered Apr 26 at 15:33

RomanRoman

7,14511134

$endgroup$

Do[threetest = 
 MatrixRank[threepoints[[i, 2, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]], 
 threepoints[[i, 3, 1 ;; 2]] - threepoints[[i, 1, 1 ;; 2]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

Do[threetest = 
 MatrixRank[threepoints[[i, 2]] - threepoints[[i, 1]], 
 threepoints[[i, 3]] - threepoints[[i, 1]]]; 
 If[threetest < 2, Break[], 1],
 i, Binomial[n, 3]]

share|improve this answer

edited Apr 26 at 18:50

answered Apr 26 at 15:33

RomanRoman

7,14511134

answered Apr 26 at 15:33

RomanRoman

7,14511134

answered Apr 26 at 15:33

RomanRoman

7,14511134

6

$begingroup$

The other thing I do is to use the stylized brackets in all of my MMA code. Stackexchange mangles it, so have to use a picture to demonstrate:

Big difference in readability.

share|improve this answer

answered Apr 26 at 18:04

MikeYMikeY

3,903916

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Also, you can put them in the subscript and they work equally. And if it's still not enough, you can use the invisible comma to separate indices. ;-)
  $endgroup$
  – Veky
  Apr 27 at 3:53
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  It’s probably worth adding how to enter these doubled brackets using the keyboard: Esc–[–[–Esc.
  $endgroup$
  – Stephen Powell
  Apr 27 at 9:17
  

  
  
  
  

add a comment | 

6

$begingroup$

The other thing I do is to use the stylized brackets in all of my MMA code. Stackexchange mangles it, so have to use a picture to demonstrate:

Big difference in readability.

share|improve this answer

answered Apr 26 at 18:04

MikeYMikeY

3,903916

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Also, you can put them in the subscript and they work equally. And if it's still not enough, you can use the invisible comma to separate indices. ;-)
  $endgroup$
  – Veky
  Apr 27 at 3:53
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  It’s probably worth adding how to enter these doubled brackets using the keyboard: Esc–[–[–Esc.
  $endgroup$
  – Stephen Powell
  Apr 27 at 9:17
  

  
  
  
  

add a comment | 

$begingroup$

The other thing I do is to use the stylized brackets in all of my MMA code. Stackexchange mangles it, so have to use a picture to demonstrate:

Big difference in readability.

share|improve this answer

answered Apr 26 at 18:04

MikeYMikeY

3,903916

$endgroup$

share|improve this answer

answered Apr 26 at 18:04

MikeYMikeY

3,903916

answered Apr 26 at 18:04

MikeYMikeY

3,903916

answered Apr 26 at 18:04

MikeYMikeY

3,903916