I found these information about computation-time of following decompositions:
- Cholesky: (1/3)*n^3 + O(n^2) --> So computation-time is O(n^3)
- LU: 2*(n^3/3) --> So computation-time is O(n^3) also (not sure)
- QR: (2/3)*n^3 + n^2 + (1/3)*n- 2 --> So computation-time is O(n^3) as well
But what I found in other documents says that Cholesky is the fastest among these three algorithms, then comes LU, and last (slowest) is QR.
How we see here, in the formulas above? (or are my formulas wrong?)