how do I check linear independence of m vectors, given the m-1 first vectors are independence?
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I have a set of m-1 vectors of size n, they are independence. I want to add another vector and to check if the m vectors are still independence. It is known m < n. I am looking for a good algorithm & running time.
Thanks
linear-algebra algorithms
$endgroup$
add a comment |
$begingroup$
I have a set of m-1 vectors of size n, they are independence. I want to add another vector and to check if the m vectors are still independence. It is known m < n. I am looking for a good algorithm & running time.
Thanks
linear-algebra algorithms
$endgroup$
$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
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– Peter
Jan 20 at 9:44
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nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48
add a comment |
$begingroup$
I have a set of m-1 vectors of size n, they are independence. I want to add another vector and to check if the m vectors are still independence. It is known m < n. I am looking for a good algorithm & running time.
Thanks
linear-algebra algorithms
$endgroup$
I have a set of m-1 vectors of size n, they are independence. I want to add another vector and to check if the m vectors are still independence. It is known m < n. I am looking for a good algorithm & running time.
Thanks
linear-algebra algorithms
linear-algebra algorithms
asked Jan 20 at 9:15
ShaqShaq
2849
2849
$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
$endgroup$
– Peter
Jan 20 at 9:44
$begingroup$
nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48
add a comment |
$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
$endgroup$
– Peter
Jan 20 at 9:44
$begingroup$
nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48
$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
$endgroup$
– Peter
Jan 20 at 9:44
$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
$endgroup$
– Peter
Jan 20 at 9:44
$begingroup$
nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
You can use the following criterion :
If you have $ m-1 $ linear independent vectors, then adding the $ m $- th vector gives again a linear independent set if and only if the $ m $ - th vector is not a linear-combination of the original $ m-1 $ vectors, in other words there are no real numbers $ a_1,cdots, a_{m-1} $ with $$sum_{j=1}^{m-1} a_jv_j=v_m$$
For the check I suggest to collect the vectors in a matrix and determine the rank.
$endgroup$
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
add a comment |
$begingroup$
Project the new vector on the others and remove.
If anything remains afterwards then they are linearly independent.
$endgroup$
add a comment |
Your Answer
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2 Answers
2
active
oldest
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2 Answers
2
active
oldest
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active
oldest
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active
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votes
$begingroup$
You can use the following criterion :
If you have $ m-1 $ linear independent vectors, then adding the $ m $- th vector gives again a linear independent set if and only if the $ m $ - th vector is not a linear-combination of the original $ m-1 $ vectors, in other words there are no real numbers $ a_1,cdots, a_{m-1} $ with $$sum_{j=1}^{m-1} a_jv_j=v_m$$
For the check I suggest to collect the vectors in a matrix and determine the rank.
$endgroup$
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
add a comment |
$begingroup$
You can use the following criterion :
If you have $ m-1 $ linear independent vectors, then adding the $ m $- th vector gives again a linear independent set if and only if the $ m $ - th vector is not a linear-combination of the original $ m-1 $ vectors, in other words there are no real numbers $ a_1,cdots, a_{m-1} $ with $$sum_{j=1}^{m-1} a_jv_j=v_m$$
For the check I suggest to collect the vectors in a matrix and determine the rank.
$endgroup$
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
add a comment |
$begingroup$
You can use the following criterion :
If you have $ m-1 $ linear independent vectors, then adding the $ m $- th vector gives again a linear independent set if and only if the $ m $ - th vector is not a linear-combination of the original $ m-1 $ vectors, in other words there are no real numbers $ a_1,cdots, a_{m-1} $ with $$sum_{j=1}^{m-1} a_jv_j=v_m$$
For the check I suggest to collect the vectors in a matrix and determine the rank.
$endgroup$
You can use the following criterion :
If you have $ m-1 $ linear independent vectors, then adding the $ m $- th vector gives again a linear independent set if and only if the $ m $ - th vector is not a linear-combination of the original $ m-1 $ vectors, in other words there are no real numbers $ a_1,cdots, a_{m-1} $ with $$sum_{j=1}^{m-1} a_jv_j=v_m$$
For the check I suggest to collect the vectors in a matrix and determine the rank.
edited Jan 20 at 9:38
answered Jan 20 at 9:24
PeterPeter
47.6k1039131
47.6k1039131
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
add a comment |
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
$begingroup$
How does this help for checking?
$endgroup$
– mathreadler
Jan 20 at 9:31
1
1
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
@mathreadler It hints at setting up a matrix equation which can be used as a check, at least that's what I gathered.
$endgroup$
– E-mu
Jan 20 at 9:33
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Sure it may hint but then maybe it can be good to at least write hint.
$endgroup$
– mathreadler
Jan 20 at 9:36
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
$begingroup$
Thanks, I got the theory. I am asking how to do it, I mean how do you check it? What kind of algorithm and hat would be the run time complexity?
$endgroup$
– Shaq
Jan 20 at 9:37
1
1
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
$begingroup$
@ShaharMazia I did a bit of searching online, from what I can see it looks like setting up a matrix equation and solving it using the Gaussian elimination algorithm is your best bet, other than randomised algorithms. See mathoverflow.net/questions/6194/….
$endgroup$
– E-mu
Jan 20 at 10:23
add a comment |
$begingroup$
Project the new vector on the others and remove.
If anything remains afterwards then they are linearly independent.
$endgroup$
add a comment |
$begingroup$
Project the new vector on the others and remove.
If anything remains afterwards then they are linearly independent.
$endgroup$
add a comment |
$begingroup$
Project the new vector on the others and remove.
If anything remains afterwards then they are linearly independent.
$endgroup$
Project the new vector on the others and remove.
If anything remains afterwards then they are linearly independent.
answered Jan 20 at 9:30
mathreadlermathreadler
14.9k72262
14.9k72262
add a comment |
add a comment |
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$begingroup$
I guess you want to use the linear independence of the $ m-1 $ vectors for a shortcut. Is that right ?
$endgroup$
– Peter
Jan 20 at 9:44
$begingroup$
nope, just it is greater the the number of vectors you have, so you cannot negate it directly.. and yes this is what I am looking for
$endgroup$
– Shaq
Jan 20 at 9:46
$begingroup$
Then, determining the rank (as mentioned in my answer) should be a suitable approach.
$endgroup$
– Peter
Jan 20 at 9:48