Feature #623
Inverse of a matrix over ZZ
Status:
Closed
Priority:
Normal
Assignee:
Category:
New Function
Target version:
Description
Inverse of a matrix over QQ works fine.
Fix code so that it works for invertible matrices over ZZ.
(I have a big example failing, I'll post here when I find a smaller one)
History
#1 Updated by John Abbott almost 9 years ago
Here is an invertible 3x3 matrix
matrix(ZZ, [[-8, -3, -6], [-2, -7, -3], [-3, 4, -1]])
Here is an invertible 4x4 matrix
matrix(ZZ, [[-2, -3, 9, 1], [9, 4, -7, -2], [-2, 2, 9, 4], [-2, 4, 0, 3]])
Here is an invertible 5x5 matrix
matrix(ZZ, [[-4, -3, -4, 3, 0], [5, 2, -5, -2, -1], [0, 0, 1, 0, 0], [5, -1, -5, 2, -3], [-1, 3, -2, -3, 2]])
Here is an invertible 6x6 matrix
matrix(ZZ, [[-2, 5, -3, -4, 3, 2], [0, 4, 1, -4, -1, -1], [5, 2, 5, 1, -1, -2], [-2, 3, -3, -1, -5, -4], [1, 1, 2, -2, -1, 2], [0, 0, -3, 3, 2, 2]])
#2 Updated by Anna Maria Bigatti almost 9 years ago
- Status changed from New to Closed
- % Done changed from 0 to 100
- Estimated time set to 3.00 h
Done.
If the matrix is over an IntegralDomain then it is mapped into FractionField.
Then the inverse is mapped back (if possible).
This might be uselessly slow if the matrix is NOT invertible, but then the user should have never asked ;-)
[the error mentioned before was just a silly error in a column for-counter]