Matvec Users’ Guide

3.4. COMPUTATION 21
This member function is a user-defined function, it’s loaded automatically into memory whenever you
launch Matvec.
For example,
> A = [3,2,1;4,5,6;9,8,7];
> A.corrcoef()
covariance
Col 1 Col 2 Col 3
Row 1 1 0.933257 0.741935
Row 2 0.933257 1 0.933257
Row 3 0.741935 0.933257 1
.covariance(B) returns a matrix whose element (i,j) is the covariance between A(i,*) and B(j,*).
For example,
> A = [1,2; 3,4; 5,6];
> B = [6,5; 2,3;8,6];
> A.covariance(B)
det
Col 1 Col 2
Row 1 2 1
Row 2 1 1
A.det() returns the determinant of A based on LU decomposition. Object A remains intact.
diag
A.diag(k), where A is a vector, returns a square matrix of order N+abs(k) with the elements of A on the
k-th diagonal, where N is the size of vector A. k=0 (default) is the main diagonal, k > 0 is above the main
diagonal and k < 0 is below the main diagonal.
A.diag(k), where A is a matrix, returns a vector formed from the elements of the k-th diagonal of A.
A.diag(B,C,D,...), where A,B,C,D,.., are all matrices, returns a block-diagonal matrix with A, B, C, ...
on the diagonal
A.diag().diag() returns a diagonal matrix.
For example,
> c = [1,2;3,4]
Col 1 Col 2
Row 1 1 2
Row 2 3 4
> c.diag()
i = 1 i = 2
1 4
> c.diag().diag()
Col 1 Col 2
Row 1 1 0
Row 2 0 4
> c.diag([5])