Re: elementwise product or sum of two vectors

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 4 Sep 2007 15:33:12 -0400
Message-ID:
<fbkbtn$bfq$1@news.datemas.de>
er wrote:

On Sep 4, 2:50 pm, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:

er wrote:

i'm trying to implement x*=y or x+=y; where x and y are containers
and *= and += are element wise i.e. x*=y is meant as
x[1]*=y[1],...,x[n]*=y[n] and likewise for +=;
i'm wondering if
a) there exists a function already defined for this purpose for the
types that i intend it for (see below)


You mean, like 'std::for_each'?

b) is there a way to make * or + a parameter so that i don't have to
write two (nearly identical) pieces of code for each (see below).


Probably. See 'std::plus' and 'std::multiplies'...

c) more generally, is there a better way to do this?


You mean, like using 'valarray', for example?

[..]


V
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like this?
std::transform(vec.begin(), vec.end(), dest.begin(),
dest.end(),std::plus<double>());


Yes, probably. Does it work?

V
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