MATLAB: failed creating a diagonal matrix

I have to make a diagonal matrix using diag command in Matlab, the numbers of the main diagonal are 1,2 and 3 . I have tried typing this code:

x=[1 2 3]; matriz=diag(x)

matriz =

1 2 3

but there is not the diagonal 3x3 matriz, please, could you help me solving this problem? Thanks! PS. As far as I'm concerned, it is supposed to show this:

B=[1 0 0;0 2 0;0 0 3]

B =

1 0 0

0 2 0

0 0 3

Answer 1

[James Tursa]

You probably have inadvertently created a variable named 'diag' in your workspace, and hence diag(x) is simply indexing into this variable. Clear that variable from your workspace and use a different name in the future. To confirm that this is the problem you can type the following:

which diag