[Numpy-discussion] Efficient ?axpy operation without copy (B += a*A)
Michael McNeil Forbes
Tue Jun 23 13:19:48 CDT 2009
Is there a way of performing vectorized ?axpy (daxpy) operations
without making copies or dropping into C?
i.e: I want to do
big = (10000,5000)
A = np.ones(big,dtype=float)
B = np.ones(big,dtype=float)
a = 1.5
B += a*A
without making any copies?
(I know I could go
A *= a
B += A
A /= a
but that is not so efficient either).
There are exposed blas daxpy operations in scipy, but in the version I
have (EPD), these also seem to make copies (though recent version seem
to be fixed by looking at the source.)
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