Is there a name for this matrix operation?
$begingroup$
Transforming a matrix by copying each element up to a certain given length ($k$) and then starting on the next row with the second element, and row after that with the third, etc. So each row is shifted by one more. For example:
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3\2 & 3 & 4\3 & 4 & 5end{bmatrix}
$$
With a parameter $k=3$ or
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3 & 4\2 & 3 & 4 & 5end{bmatrix}
$$
With a parameter $k=4$.
linear-algebra
$endgroup$
add a comment |
$begingroup$
Transforming a matrix by copying each element up to a certain given length ($k$) and then starting on the next row with the second element, and row after that with the third, etc. So each row is shifted by one more. For example:
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3\2 & 3 & 4\3 & 4 & 5end{bmatrix}
$$
With a parameter $k=3$ or
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3 & 4\2 & 3 & 4 & 5end{bmatrix}
$$
With a parameter $k=4$.
linear-algebra
$endgroup$
1
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
1
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
1
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01
add a comment |
$begingroup$
Transforming a matrix by copying each element up to a certain given length ($k$) and then starting on the next row with the second element, and row after that with the third, etc. So each row is shifted by one more. For example:
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3\2 & 3 & 4\3 & 4 & 5end{bmatrix}
$$
With a parameter $k=3$ or
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3 & 4\2 & 3 & 4 & 5end{bmatrix}
$$
With a parameter $k=4$.
linear-algebra
$endgroup$
Transforming a matrix by copying each element up to a certain given length ($k$) and then starting on the next row with the second element, and row after that with the third, etc. So each row is shifted by one more. For example:
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3\2 & 3 & 4\3 & 4 & 5end{bmatrix}
$$
With a parameter $k=3$ or
$$begin{bmatrix}1\2\3\4\5end{bmatrix}
rightarrow
begin{bmatrix}1 & 2 & 3 & 4\2 & 3 & 4 & 5end{bmatrix}
$$
With a parameter $k=4$.
linear-algebra
linear-algebra
edited Dec 2 '18 at 7:38
Tianlalu
3,08121038
3,08121038
asked Dec 1 '18 at 20:49
Ken FehlingKen Fehling
1135
1135
1
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
1
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
1
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01
add a comment |
1
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
1
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
1
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01
1
1
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
1
1
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
1
1
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
The operation looks a little too particular to me to have a (well known) name.
The resulting matrix is like a Toeplitz matrix (except that it's constant along the anti-diagonals), could be regarded as some sort of "toeplitzation" (ugh)...
For example, the second example in Matlab/Octave:
>> fliplr(toeplitz([4,5],[4,3,2,1]))
ans =
1 2 3 4
2 3 4 5
$endgroup$
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
add a comment |
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1 Answer
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$begingroup$
The operation looks a little too particular to me to have a (well known) name.
The resulting matrix is like a Toeplitz matrix (except that it's constant along the anti-diagonals), could be regarded as some sort of "toeplitzation" (ugh)...
For example, the second example in Matlab/Octave:
>> fliplr(toeplitz([4,5],[4,3,2,1]))
ans =
1 2 3 4
2 3 4 5
$endgroup$
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
add a comment |
$begingroup$
The operation looks a little too particular to me to have a (well known) name.
The resulting matrix is like a Toeplitz matrix (except that it's constant along the anti-diagonals), could be regarded as some sort of "toeplitzation" (ugh)...
For example, the second example in Matlab/Octave:
>> fliplr(toeplitz([4,5],[4,3,2,1]))
ans =
1 2 3 4
2 3 4 5
$endgroup$
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
add a comment |
$begingroup$
The operation looks a little too particular to me to have a (well known) name.
The resulting matrix is like a Toeplitz matrix (except that it's constant along the anti-diagonals), could be regarded as some sort of "toeplitzation" (ugh)...
For example, the second example in Matlab/Octave:
>> fliplr(toeplitz([4,5],[4,3,2,1]))
ans =
1 2 3 4
2 3 4 5
$endgroup$
The operation looks a little too particular to me to have a (well known) name.
The resulting matrix is like a Toeplitz matrix (except that it's constant along the anti-diagonals), could be regarded as some sort of "toeplitzation" (ugh)...
For example, the second example in Matlab/Octave:
>> fliplr(toeplitz([4,5],[4,3,2,1]))
ans =
1 2 3 4
2 3 4 5
answered Dec 1 '18 at 21:25
leonbloyleonbloy
40.5k645107
40.5k645107
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
add a comment |
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
1
1
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
$begingroup$
Thanks! This opened up some good things for me to look into. From Toeplitz I found Hankel which seems like I can use to do at least something close to what I need.
$endgroup$
– Ken Fehling
Dec 1 '18 at 21:43
1
1
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
$begingroup$
If you are looking for ways to do this in Python, you may also be interested in vstack.
$endgroup$
– Erik André
Dec 2 '18 at 7:56
add a comment |
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1
$begingroup$
If such operation is useful, it certainly has a name. And conversely.
$endgroup$
– Yves Daoust
Dec 1 '18 at 21:05
1
$begingroup$
Thinking to a fixed length window (length = 3 or 2 in your example) : you are sliding this window on the message "1 2 3 4 5" and you gather the results in a new matrix : thus it has something common with discrete convolution but I don't see any "closed form" matrix expression that can render this operation...
$endgroup$
– Jean Marie
Dec 1 '18 at 22:15
1
$begingroup$
I would call the 1st operation Hankelization.
$endgroup$
– Rodrigo de Azevedo
Dec 2 '18 at 8:01