# parallel map and dot product

Hudson, Rick rick.hudson at intel.com
Thu Apr 4 12:06:40 PDT 2013

```In this case it is the same as with a normal array.

function dotProduct(v1, v2) {
return v1.map(function (e, i) {return e*v2[i];}).reduce(function (a, b) {return a+b;});
}

-        Rick

From: es-discuss-bounces at mozilla.org [mailto:es-discuss-bounces at mozilla.org] On Behalf Of Norm Rubin
Sent: Thursday, April 04, 2013 2:31 PM
To: es-discuss at mozilla.org
Subject: parallel map and dot product

I've started to read through the parallel JavaScript  proposal  and have a novice question
How would you write a dot product
Given:

P1 = parallelArray(1,2,3)
P2 = ParallelArray(4,5,6)

We want to compute
1*4 + 2*5 + 3*6

As far as I can tell, you need a reduce to do the sums, so you first need to construct
P12 = ParallelArray(1*4, 2*5, 3*6)

Is there a way to generate this using map?

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