spmatrix error110: weighting matrix W already exists

[iris lee]

Dear all,

It's odd that when I put in the code :

spmatrix create contiguity W if year == 1995

I get :
weighting matrix W already exists
r(110);

However, when I put in:

    cap mat drop W
    matrix list  W

I get nothing. Then I just change the name of weight

    spmatrix create contiguity weight if year == 1995

It says:
weighting matrix in w contains 61 islands

I think that's ok finally but I don't know how to delete the weight matrix W or w. Thanks for any help!

Regards,
Iris

[iris lee]

    spmatrix drop   w
    spmatrix drop   W

[iris lee]

OR use this to delete all spatial weight matrix:

    spmatrix clear