forked from M-Labs/nalgebra
Merge pull request #669 from daingun/patch-2
Use same algorithm to solve 2x2 eigenvalue problem
This commit is contained in:
commit
d78309b1fd
@ -309,16 +309,17 @@ where
|
|||||||
let hmn = t[(m, n)];
|
let hmn = t[(m, n)];
|
||||||
let hnn = t[(n, n)];
|
let hnn = t[(n, n)];
|
||||||
|
|
||||||
let tra = hnn + hmm;
|
// NOTE: use the same algorithm as in compute_2x2_eigvals.
|
||||||
let det = hnn * hmm - hnm * hmn;
|
let val = (hmm - hnn) * crate::convert(0.5);
|
||||||
let discr = tra * tra * crate::convert(0.25) - det;
|
let discr = hnm * hmn + val * val;
|
||||||
|
|
||||||
// All 2x2 blocks have negative discriminant because we already decoupled those
|
// All 2x2 blocks have negative discriminant because we already decoupled those
|
||||||
// with positive eigenvalues..
|
// with positive eigenvalues.
|
||||||
let sqrt_discr = NumComplex::new(N::zero(), (-discr).sqrt());
|
let sqrt_discr = NumComplex::new(N::zero(), (-discr).sqrt());
|
||||||
|
|
||||||
out[m] = NumComplex::new(tra * crate::convert(0.5), N::zero()) + sqrt_discr;
|
let half_tra = (hnn + hmm) * crate::convert(0.5);
|
||||||
out[m + 1] = NumComplex::new(tra * crate::convert(0.5), N::zero()) - sqrt_discr;
|
out[m] = NumComplex::new(half_tra, N::zero()) + sqrt_discr;
|
||||||
|
out[m + 1] = NumComplex::new(half_tra, N::zero()) - sqrt_discr;
|
||||||
|
|
||||||
m += 2;
|
m += 2;
|
||||||
}
|
}
|
||||||
|
Loading…
Reference in New Issue
Block a user