*** WARNING ***                         CP =     489.641   TIME= 16:13:34 Real constant 7 referenced by at least element types 1 and 7.           

*** ERROR ***                           CP =     491.984   TIME= 16:13:36 The inversion subroutine was supplied with a singular matrix.           

 求高手解答  ：The inversion subroutine was supplied with a singular matrix.？？？？