[Numpy-discussion] help with translating some matlab
Neal Becker
ndbecker2@gmail....
Fri Feb 18 12:50:49 CST 2011
Neal Becker wrote:
> My translation is:
>
> x1 = rcv[n:n-N:-1]
>
> z = np.dot (P, x1.conj().transpose())
>
> g = z / (_lambda + np.dot (x1, z))
>
> y = np.dot (h, x1.conj().transpose())
>
> e = x[n-N/2] - y
>
> h += np.dot (e, g.conj().transpose())
>
> P = (P - np.dot (g, z.conj().transpose()))/_lambda
>
> But it doesn't work.
>
> You say z should be a column vector. I got:
> In [138]: x1.shape
> Out[138]: (64,)
>
> In [139]: z.shape
> Out[139]: (64,)
>
> Clearly, I did something wrong here.
I think I've got it. In numpy, a 'vector' is a row vector. If I want to turn a
row vector into a column vector, transpose doesn't work. I need to use newaxis
for that. So the whole translation is:
x1 = rcv[n:n-N:-1]
z = np.dot (P, x1.conj()[:,np.newaxis])
g = z / (_lambda + np.dot (x1, z))
y = np.dot (h, x1.conj()[:,np.newaxis])
e = x[n] - y
h += np.dot (e, g.conj().transpose())
P = (P - np.dot (g, z.conj().transpose()))/_lambda
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