Mercurial > hg > octave-nkf
comparison scripts/linear-algebra/rank.m @ 4:b4df021f796c
[project @ 1993-08-08 01:26:08 by jwe]
Initial revision
| author | jwe |
|---|---|
| date | Sun, 08 Aug 1993 01:26:08 +0000 |
| parents | |
| children | 16a24e76d6e0 |
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| 3:9a4c07481e61 | 4:b4df021f796c |
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| 1 function retval = rank (A, tol) | |
| 2 | |
| 3 # usage: rand (a, tol) | |
| 4 # | |
| 5 # Return the rank of the matrix a. The rank is taken to be the number | |
| 6 # of singular values of a that are greater than tol. | |
| 7 # | |
| 8 # If the second argument is omitted, it is taken to be | |
| 9 # | |
| 10 # tol = max (size (a)) * sigma (1) * eps; | |
| 11 # | |
| 12 # where eps is machine precision and sigma is the largest singular | |
| 13 # value of a. | |
| 14 | |
| 15 if (nargin == 1) | |
| 16 sigma = svd (A); | |
| 17 tolerance = max (size (A)) * sigma (1) * eps; | |
| 18 elseif (nargin == 2) | |
| 19 tolerance = tol; | |
| 20 else | |
| 21 error ("usage: rank (A)"); | |
| 22 endif | |
| 23 retval = sum (sigma > tolerance); | |
| 24 | |
| 25 endfunction |