[SciPy-dev] small bug(s) in scipy.linalg
Pearu Peterson
pearu at cens.ioc.ee
Mon Feb 10 04:27:39 CST 2003
On 10 Feb 2003, Alexander Schmolck wrote:
> I think scipy.linalg.basic has a few issues with 1D vectors vs row and column
> vectors (respective shapes: (n,), (1,n), (n,1)). It would seem clear to me,
> for example that `norm` ought to produce exactly the same with a 1D vector as
> with a row vector or column vector. Currently it doesn't,
-1 for considering it as a bug.
For generality, I'd leave to users to decide whether (1,n) or
(n,1) shaped matrices should regarded as vectors.
It is simple to call norm(ravel(x)) (even if x is (n,) shaped).
However, if norm() would automatically map x -> ravel(x) for one
row/column matrix x, as suggested, then this would make writing generic
algorithms harder (check shapes, split program flow, etc).
How about introducing a convenience function
def vnorm(x):
return norm(ravel(x))
?
> and the very common case of the 2 norm for a vector is, I think,
> handled inefficiently.
+1 for fixing this.
Pearu
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