我用的是267个地级市14年的面板数据，现在想使用空间tobit模型，但运行命令时出现了如下的问题：
xtset citycode year
sptobitsdmxt y x1 x2 x3, wmfile(W1) ll(0) nc(267) inv mfx(log) tolog robust
>>
*** Binary (0/1) Weight Matrix: 3738x3738 - NC=267 NT=14 (Non Normalized)
matsize too small
    You have attempted to create a matrix with too many rows or columns or attempted to fit a model with too many variables.
    You need to increase matsize; it is currently 400.  Use set matsize; see help matsize.

    If you are using factor variables and included an interaction that has lots of missing cells, either increase matsize or
    set emptycells drop to reduce the required matrix size; see help set emptycells.

    If you are using factor variables, you might have accidentally treated a continuous variable as a categorical, resulting
    in lots of categories.  Use the c. operator on such variables.
r(908);


请问我是哪里出现了问题？我是stata新手，求大神指教！