Subject: [boost] [qvm] scalar_cast
From: Nikolay Mladenov (nikolay.mladenov_at_[hidden])
Date: 2012-11-03 19:00:38
I am trying qvm in a small project that uses complex numbers and have
expressions of the kind :
cv3 = c1*rv3_1 + c2*rv3_2
(the v3's are vectors, the c's are complex and the r's are real).
I wrote it as :
but this seems to invoke 6 complex constructors (unnecessarily)
I have not tested to see if the constructors will be optimized away,
but it seems to me that if :
v_traits<vector_scalar_cast_>::scalar_type == complex , bit
v_traits<vector_scalar_cast_>::r/ir return real
the expression will compile and no complex constructors will be invoked.
It seems to me that there is a need for another kind of scalar_cast that
just adapts the v_traits<>:scalar_type but leaves the r() and ir() unchanged
Another question I have is if there is a reason why vector*scalar works but
scalar*vector does not?
Thanks in advance,
PS I can send patches if you'd like.
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