extern int nnode, nelem, nmats, nplds;
extern int ndgrs;
extern struct { 
                 float x,y;
                 int   bc;
                 int   u,v,theta; } node_info[];
extern struct {
                 int nl,nr,mat;  }  elem_info[];
extern struct {
                 float ea,ei; }     mat_info[];
extern struct {
                 int   to_point;
                 float px,py,m; }   load_info[];


