# Tensor Calculation

1. Mar 24, 2010

### frasool

Hi
I have the following tensor and i need to reduce to a scalor quantity:
3 by 3 matrix
4150470.48 , 317.64, -353.42
317.64, 2047101.07,-1407556.61
-353.42, -1407566.61, 2284136.55

Please its urgent and any help would be greatly appreciated!!
Regards
Faizan

2. Mar 25, 2010

### HallsofIvy

First, a matrix is NOT a tensor- just as a sequence of numbers is not a vector. A matrix can represent a tensor but you have to have some tensor space structure and you haven't told us HOW that matrix represents a tensor (i.e. what basis you are using).

The simplest way derive a single number from a matrix is the contraction- in terms of a matrix representation, it is just the "trace": add the numbers on the main diagonal. But surely there is more to this than just getting some number from the matrix?

3. Mar 25, 2010

### frasool

I got these values from solidworks but for my wheel design i need a single value for the moment of inertia. The values i gave you represent Ixx Ixy Ixz and then Iyx Iyy Iyz and Izx Izy Izz. And it says these were taken from the outer coordinate system!. So its not just a matrix it is a tensor. Could you help me out with how to proceed with this problem !

Regards
Faizan