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| author | Tyler Moncur <mtmoncur@gmail.com> | 2019-04-08 17:00:10 -0600 |
|---|---|---|
| committer | Tyler Moncur <mtmoncur@gmail.com> | 2019-04-08 17:21:36 -0600 |
| commit | 732d52a4c3cd91b8a2e20b99823fcd233dc32112 (patch) | |
| tree | e0e83571bb563ead4ebbe5f8967b898c78aef518 | |
| parent | 96cacd74e50d972df8f6c8704b0f4b3c3dfbc81c (diff) | |
| download | numpy-732d52a4c3cd91b8a2e20b99823fcd233dc32112.tar.gz | |
ENH: rotate companion matrix for all polynomial bases
| -rw-r--r-- | numpy/polynomial/chebyshev.py | 3 | ||||
| -rw-r--r-- | numpy/polynomial/hermite.py | 3 | ||||
| -rw-r--r-- | numpy/polynomial/hermite_e.py | 3 | ||||
| -rw-r--r-- | numpy/polynomial/laguerre.py | 3 | ||||
| -rw-r--r-- | numpy/polynomial/legendre.py | 3 | ||||
| -rw-r--r-- | numpy/polynomial/polynomial.py | 5 |
6 files changed, 13 insertions, 7 deletions
diff --git a/numpy/polynomial/chebyshev.py b/numpy/polynomial/chebyshev.py index 836f47363..c37b2c6d6 100644 --- a/numpy/polynomial/chebyshev.py +++ b/numpy/polynomial/chebyshev.py @@ -1743,7 +1743,8 @@ def chebroots(c): if len(c) == 2: return np.array([-c[0]/c[1]]) - m = chebcompanion(c) + # rotated companion matrix reduces error + m = chebcompanion(c)[::-1,::-1] r = la.eigvals(m) r.sort() return r diff --git a/numpy/polynomial/hermite.py b/numpy/polynomial/hermite.py index dcd0a2b4d..3870d1054 100644 --- a/numpy/polynomial/hermite.py +++ b/numpy/polynomial/hermite.py @@ -1476,7 +1476,8 @@ def hermroots(c): if len(c) == 2: return np.array([-.5*c[0]/c[1]]) - m = hermcompanion(c) + # rotated companion matrix reduces error + m = hermcompanion(c)[::-1,::-1] r = la.eigvals(m) r.sort() return r diff --git a/numpy/polynomial/hermite_e.py b/numpy/polynomial/hermite_e.py index 48e5eab20..b12c0d792 100644 --- a/numpy/polynomial/hermite_e.py +++ b/numpy/polynomial/hermite_e.py @@ -1471,7 +1471,8 @@ def hermeroots(c): if len(c) == 2: return np.array([-c[0]/c[1]]) - m = hermecompanion(c) + # rotated companion matrix reduces error + m = hermecompanion(c)[::-1,::-1] r = la.eigvals(m) r.sort() return r diff --git a/numpy/polynomial/laguerre.py b/numpy/polynomial/laguerre.py index 41d15142a..e103dde92 100644 --- a/numpy/polynomial/laguerre.py +++ b/numpy/polynomial/laguerre.py @@ -1475,7 +1475,8 @@ def lagroots(c): if len(c) == 2: return np.array([1 + c[0]/c[1]]) - m = lagcompanion(c) + # rotated companion matrix reduces error + m = lagcompanion(c)[::-1,::-1] r = la.eigvals(m) r.sort() return r diff --git a/numpy/polynomial/legendre.py b/numpy/polynomial/legendre.py index d56e2ae2c..9eec9740d 100644 --- a/numpy/polynomial/legendre.py +++ b/numpy/polynomial/legendre.py @@ -1505,7 +1505,8 @@ def legroots(c): if len(c) == 2: return np.array([-c[0]/c[1]]) - m = legcompanion(c) + # rotated companion matrix reduces error + m = legcompanion(c)[::-1,::-1] r = la.eigvals(m) r.sort() return r diff --git a/numpy/polynomial/polynomial.py b/numpy/polynomial/polynomial.py index bada4321e..afa330502 100644 --- a/numpy/polynomial/polynomial.py +++ b/numpy/polynomial/polynomial.py @@ -1428,8 +1428,9 @@ def polyroots(c): if len(c) == 2: return np.array([-c[0]/c[1]]) - m = polycompanion(c) - r = la.eigvals(m[::-1,::-1]) + # rotated companion matrix reduces error + m = polycompanion(c)[::-1,::-1] + r = la.eigvals(m) r.sort() return r |