# upmat, upmat1¶

## Purpose¶

Returns the upper portion of a matrix. upmat() returns the main diagonal and every element above. upmat1() is the same except it replaces the main diagonal with ones.

## Format¶

u = upmat(x)
u = upmat1(x)
Parameters: x (NxK matrix) – data u (NxK matrix) – containing the upper elements of x. The lower elements are replaced with zeros. upmat() returns the main diagonal intact. upmat1() replaces the main diagonal with ones.

## Examples¶

x = { 7  2 -1,
2  3 -2,
4 -2  8 };

u = upmat(x);
u1 = upmat1(x);


The resulting matrices are:

    7  2 -1       1  2 -1
u = 0  3 -2  u1 = 0  1 -2
0  0  8       0  0  1


diag.src