Status: New
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 1401 by jorn.baayen: 'simplify' not idempotent?
http://code.google.com/p/sympy/issues/detail?id=1401
For certain symbolic matrices calling 'eigenvects' will return
eigenvalues, but no eigenvectors. Looking into this it turns
out that the problem is in simplify(), as called from 'eigenvects' ->
'nullspace' -> 'rref'. If I replace every occurrence of 'simplify()'
in 'rref' with 'simplify(simplify())', eigenvectors are returned.
This raises the question of whether 'simplify' shouldn't be idempotent?
---- testcase follows ----
UA = Symbol("UA")
K_i = Symbol("K_i")
K_w = Symbol("K_w")
A = Matrix([[-K_i - UA + K_i**2/(K_i + K_w), K_i*K_w/(K_i + K_w)],
[ K_i*K_w/(K_i + K_w), -K_w + K_w**2/(K_i + K_w)]])
A.eigenvects()
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