stata中对SVAR进行限制后显示rank不足要如何解决

我的代码是：matrix A = (1,.,0,0,.,0,0\0,1,0,0,0,0,0\.,.,1,.,0,.,0\.,.,0,1,.,0,0\.,.,0,0,1,0,0\.,.,0,.,.,1,0\.,.,.,.,.,.,1)matrix B = (.,0,0,0,0,0,0\0,.,0,0,0,0,0\0,0,.,0,0,0,0\0,0,0,.,0,0,0\0,0,0,0,.,0,0\0,0,0,0,0,.,0\0,0,0,0,0,0,.)
svar dluc dlui dlur dlcc dlcnm dlci dlrer,aeq(A) beq(B) lags(1/3) var

结果出来是：These constraints place 70 independent constraints on A and B
The order condition requires at least 70 constraints.
Identification requires a rank of 98, but the identification matrix only has rank 97
求问这是为什么，要怎么解决
急求！