The trace is the sum of the elements on the leading diagonal.
trace = sum(m_{ii})
So in the case of a 3x3 matrix:
m_{00}  
m_{11}  
m_{22} 
trace = m_{00}+m_{11}+m_{22}
The trace is the sum of the elements on the leading diagonal.
trace = sum(m_{ii})
So in the case of a 3x3 matrix:
m_{00}  
m_{11}  
m_{22} 
trace = m_{00}+m_{11}+m_{22}
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