% FIGURE 5.4.1
%                              BREAK POINTS ARE XPTS(K), K=1,N+1
%                              UNKNOWNS ARE A(I), I=1,M
      global N
      global XPTS
      global M
      global A
      global OMEGA
      global LOCATE
      OMEGA = 'OMEGA541';
      LOCATE = 'LOCATE541';
%                              NSUBS = NUMBER OF SUBINTERVALS
      NSUBS = 4;
      N = NSUBS;
      M = 2*NSUBS+1;
      ALPHA = 3.636;
      for K=1:N+1
         XPTS(K) = ((K-1)/N)^ALPHA;
      end
%                              CALCULATE RIGHT HAND SIDE VECTOR AND
%                              COEFFICIENT MATRIX
      L = 3;
      for K=1:M
         B(K) = 1.1*PHI(K,0,1.0);
         for I=max(K-L,1):min(K+L,M)
            AMAT(K,L+1+I-K) = GAUSS('FUNA541',K,I);
         end
      end
%                              SOLVE LINEAR SYSTEM USING BAND SOLVER
      A = LBAND(AMAT,B,M,L);
%                              CALCULATE MAXIMUM ERROR
      ERMAX = 0.0;
      for J=0:100
         X = J/100.0;
         ERR = abs(USOL(0,X,1,M) - X^1.1);
         ERMAX = max(ERMAX,ERR);
      end
      ERMAX