scalar product between vectors

[Dany]

Hi, someone could tell me how I could do the dot product between vectors?

[Craig Reynolds]

OpenSteer's Vec3 has a dot method for computing the scalar product of two Vec3s:

> a.dot(b)

I think you are talking about your "feature vectors" which may be an STL std::vector?  In any case the basic idea would be something like:

> float scalarProduct = 0;
>
> for (int i=0; i<featureVectorLength; i++) scalarProduct += a_ * b ;

Or am I missing the point of your question?

_

[Dany]

Hi, the property "feature" is a Vec3 type…I must do the dot product of each vehicle with its neighbors.
I created 3 groups of 10 vehicles in this way:

Agente* agenti;
Agente* a_agenti;
Agente* b_agenti;
Agente* c_agenti;

"agenti" refers to all vehicles. Correct?

In the method I gave each group different values for the vector of "features" and then I have made every agent could do the dot product with the neighbors .. okay as I did?

***void Agente::updateFeatures(Vec3 *features)***
{

a_agenti->features.set(1,0,0);
b_agenti->features.set(0,1,0);
c_agenti->features.set(0,0,1);

for(int q=0; q<29; q++)
{
const float maxRadius = 3 * maxSpeed() * 2;
neighbors.clear();
proximityToken->findNeighbors (position(), maxRadius,neighbors);

for (size_t neighborelementindex = 0; neighborelementindex < neighbors.size(); neighborelementindex++ )
{
    (Agente*)neighbors;
Agente* aneighbor = (Agente*)neighbors;

float diff = diff + ( (agenti.features).dot(aneighbor->features) );
}
}
}