I have looked at the documentation and i am not exactly clear how I can multiply a mtrix and vector, can somone help? For instance if i had:

TMatrixD * m = TMatrixD(4,4);

m->UnitMatrix();

TVectorD * v = TVectorD(4);

for (Int_t i=0; i<4; i++)

{

v(i)=(Double_t) i;

}

And I wanted to calculate:

m * v = y

(which of course gives y==v) how can i do this?

Thanks

Hi,

I modified your code to make it correct C++ and perform a matrix/vector

multiplication :

```
{
TMatrixD *m = new TMatrixD(4,4);
m->UnitMatrix();
TVectorD *v = new TVectorD(4);
for (Int_t i=0; i<4; i++)
{
*v(i)=(Double_t) i;
}
*v *= *m;
v->Print();
}
```

In the latest production version 5.08, also the “*” operator has been

added so that you could also do:

TVectorD v2 = *m * *v;

Eddy

Eddy,

Thanks!!!

(sorry for the syntax errors it was late when I wrote the post )

Alex