double *fd1d_heat_steady ( int n, double a, double b, double ua, double ub, 
  double k ( double x ), double f ( double x ), double x[] );
double *r83np_fs ( int n, double a[], double b[] );
void r8mat_write ( char *output_filename, int m, int n, double table[] );
double *r8vec_even ( int n, double alo, double ahi );
void timestamp ( void );