Matlab对角矩阵

1、正对角

>>  v = [1 2 3 4 5 6 7 8 9]

v =

     1     2     3     4     5     6     7     8     9

>>  diag(v)

ans =

     1     0     0     0     0     0     0     0     0
     0     2     0     0     0     0     0     0     0
     0     0     3     0     0     0     0     0     0
     0     0     0     4     0     0     0     0     0
     0     0     0     0     5     0     0     0     0
     0     0     0     0     0     6     0     0     0
     0     0     0     0     0     0     7     0     0
     0     0     0     0     0     0     0     8     0
     0     0     0     0     0     0     0     0     9

2、上对角

>>  v = [1 2 3 4 5 6 7 8 9]

v =

     1     2     3     4     5     6     7     8     9

>> diag(v,1)

ans =

     0     1     0     0     0     0     0     0     0     0
     0     0     2     0     0     0     0     0     0     0
     0     0     0     3     0     0     0     0     0     0
     0     0     0     0     4     0     0     0     0     0
     0     0     0     0     0     5     0     0     0     0
     0     0     0     0     0     0     6     0     0     0
     0     0     0     0     0     0     0     7     0     0
     0     0     0     0     0     0     0     0     8     0
     0     0     0     0     0     0     0     0     0     9
     0     0     0     0     0     0     0     0     0     0

3、下对角

>>  v = [1 2 3 4 5 6 7 8 9]

v =

     1     2     3     4     5     6     7     8     9

>> diag(v,-1)

ans =

     0     0     0     0     0     0     0     0     0     0
     1     0     0     0     0     0     0     0     0     0
     0     2     0     0     0     0     0     0     0     0
     0     0     3     0     0     0     0     0     0     0
     0     0     0     4     0     0     0     0     0     0
     0     0     0     0     5     0     0     0     0     0
     0     0     0     0     0     6     0     0     0     0
     0     0     0     0     0     0     7     0     0     0
     0     0     0     0     0     0     0     8     0     0
     0     0     0     0     0     0     0     0     9     0