"CODE" 33302;
 "PROCEDURE" FEM LAG SKEW(X, Y, N, Q, R, F, ORDER, E);
 "VALUE" N, ORDER; "INTEGER" N, ORDER;
 "REAL" "PROCEDURE" Q, R, F;
 "ARRAY" X, Y, E;
 "BEGIN" "INTEGER" L, L1;
   "REAL" XL1, XL, H, A12, A21, B1, B2, TAU1, TAU2, CH, TL, G, YL, PP,
    E1, E2, E3, E4, E5, E6;
   "ARRAY" T, SUPER, SUB, CHI, GI[0:N-1];

   "PROCEDURE" ELEMENT MAT VEC EVALUATION 1;
   "BEGIN" "OWN" "REAL" Q2, R2, F2;
    "REAL" Q1, R1, F1, H2, S12;
    "IF" L=1 "THEN"
    "BEGIN" Q2:= Q(XL1); R2:= R(XL1); F2:= F(XL1) "END";
    H2:= H/2; S12:= - 1/H;
    Q1:= Q2; Q2:= Q(XL);
    R1:= R2; R2:= R(XL);
    F1:= F2; F2:= F(XL);
    B1:= H2*F1; B2:= H2*F2;
    TAU1:= H2*R1; TAU2:= H2*R2;
    A12:= S12 + Q1/2; A21:= S12 - Q2/2
   "END" ELEMENT MAT VEC EV.;

   "PROCEDURE" ELEMENT MAT VEC EVALUATION 2;
   "BEGIN" "OWN" "REAL" Q3, R3, F3;
    "REAL" Q1, Q2, R1, R2, F1, F2, S12, S13, S22, X2, H6, H15,
      C12, C32, A13, A31, A22, A23, A32, B3, TAU3;
    "IF" L=1 "THEN"
    "BEGIN" Q3:= Q(XL1); R3:= R(XL1); F3:= F(XL1) "END";

    X2:= (XL1 + XL)/2; H6:= H/6; H15:= H/1.5;
    Q1:= Q3; Q2:= Q(X2); Q3:= Q(XL);
    R1:= R3; R2:= R(X2); R3:= R(XL);
    F1:= F3; F2:= F(X2); F3:= F(XL);
    B1:= H6*F1; B2:= H15*F2; B3:= H6*F3;
    TAU1:= H6*R1; TAU2:= H15*R2; TAU3:= H6*R3;
    S12:= - 1/H/0.375; S13:= - S12/8; S22:= - 2*S12;
    A12:= S12 + Q1/1.5; A13:= S13 - Q1/6;
    A21:= S12 - Q2/1.5; A23:= S12 + Q2/1.5; A22:= S22 + TAU2;
    A31:= S13 + Q3/6; A32:= S12 - Q3/1.5;
    "COMMENT" STATIC CONDENSATION;
    C12:= - A12/A22; C32:= - A32/A22;
    A12:= A13 + C12*A23; A21:= A31 + C32*A21;
    B1:= B1 + C12*B2; B2:= B3 + C32*B2;
    TAU1:= TAU1 + C12*TAU2; TAU2:= TAU3 + C32*TAU2
   "END" ELEMENT MAT VEC EVALUATION 2
   "PROCEDURE" ELEMENT MAT VEC EVALUATION 3;
   "BEGIN" "OWN" "REAL" Q4, R4, F4;
    "REAL" Q1, Q2, Q3, R1, R2, R3, F1, F2, F3,
     S12, S13, S14, S22, S23, X2, X3, H12, H24,
     DET, C12, C13, C42, C43, A13, A14, A22, A23,
     A24, A31, A32, A33, A34, A41, A42, A43,
     B3, B4, TAU3, TAU4;

    "IF" L=1 "THEN"
    "BEGIN" Q4:= Q(XL1); R4:= R(XL1); F4:= F(XL1) "END";
    X2:= XL1 + 0.27639320225*H; X3:= XL - X2 + XL1;
    H12:= H/12; H24:= H/2.4;
    Q1:= Q4; Q2:= Q(X2); Q3:= Q(X3); Q4:= Q(XL);
    R1:= R4; R2:= R(X2); R3:= R(X3); R4:= R(XL);
    F1:= F4; F2:= F(X2); F3:= F(X3); F4:= F(XL);
    S12:= -4.8784183052080/H; S13:= 0.7117516385414/H;
    S14:= -.16666666666667/H; S23:= 25*S14; S22:= -2*S23;
    B1:= H12*F1; B2:= H24*F2; B3:= H24*F3; B4:= H12*F4;
    TAU1:= H12*R1; TAU2:= H24*R2; TAU3:= H24*R3; TAU4:= H12*R4;
    A12:= S12 + 0.67418082864578*Q1;
    A13:= S13 - 0.25751416197912*Q1;
    A14:= S14 + Q1/12;
    A21:= S12 - 0.67418082864578*Q2;
    A22:= S22 + TAU2;
    A23:= S23 + 0.93169499062490*Q2;
    A24:= S13 - 0.25751416197912*Q2;
    A31:= S13 + 0.25751416197912*Q3;
    A32:= S23 - 0.93169499062490*Q3;
    A33:= S22 + TAU3;
    A34:= S12 + 0.67418082864578*Q3;
    A41:= S14 - Q4/12;
    A42:= S13 + 0.25751416197912*Q4;
    A43:= S12 - 0.67418082864578*Q4;
    "COMMENT" STATIC CONDENSATION;
    DET:= A22*A33 - A23*A32;
    C12:= (A13*A32 - A12*A33)/DET;
    C13:= (A12*A23 - A13*A22)/DET;
    C42:= (A32*A43 - A42*A33)/DET;
    C43:= (A42*A23 - A43*A22)/DET;
    TAU1:= TAU1 + C12*TAU2 + C13*TAU3 ;
    TAU2:= TAU4 + C42*TAU2 + C43*TAU3;
    A12:= A14 + C12*A24 + C13*A34;
    A21:= A41 + C42*A21 + C43*A31;
    B1:= B1 + C12*B2 + C13*B3;
    B2:= B4 + C42*B2 + C43*B3
   "END" ELEMENT MAT VEC EVALUATION 3
   "PROCEDURE" BOUNDARY CONDITIONS;
   "IF" L=1 "AND" E2 = 0 "THEN"
   "BEGIN" TAU1:= 1; B1:= E3/E1; A12:= 0 "END"
   "ELSE" "IF" L=1 "AND" E2 ^= 0 "THEN"
   "BEGIN" TAU1:= TAU1 - E1/E2; B1:= B1 - E3/E2
   "END" "ELSE" "IF" L=N "AND" E5 = 0 "THEN"
   "BEGIN" TAU2:= 1; A21:= 0; B2:= E6/E4;
   "END" "ELSE" "IF" L=N "AND" E5 ^= 0 "THEN"
   "BEGIN" TAU2:= TAU2 + E4/E5; B2:= B2 + E6/E5
   "END" B.C.1;

   "PROCEDURE" FORWARD BABUSKA;
   "IF" L=1 "THEN"
   "BEGIN" CHI[0]:= CH:= TL:= TAU1; T[0]:= TL;
      GI[0]:= G:= YL:= B1; Y[0]:= YL;
      SUB[0]:= A21; SUPER[0]:= A12;
      PP:= A21/(CH - A12); CH:= TAU2 - CH*PP;
      G:= B2 - G*PP; TL:= TAU2; YL:= B2
   "END" "ELSE"
   "BEGIN" CHI[L1]:= CH:= CH + TAU1;
      GI[L1]:= G:= G + B1;
      SUB[L1]:= A21; SUPER[L1]:= A12;
      PP:= A21/(CH - A12); CH:= TAU2 - CH*PP;
      G:= B2 - G*PP; T[L1]:= TL + TAU1; TL:= TAU2;
      Y[L1]:= YL +  B1; YL:= B2
   "END" FORWARD BABUSKA;

   "PROCEDURE" BACKWARD BABUSKA;
   "BEGIN"PP:= YL; Y[N]:= G/CH;
      G:= PP; CH:= TL; L:= N;
      "FOR" L:= L - 1 "WHILE" L >= 0 "DO"
      "BEGIN" PP:= SUPER[L]/(CH - SUB[L]);
        TL:= T[L]; CH:= TL - CH*PP;
        YL:= Y[L]; G:= YL - G*PP;
        Y[L]:=(GI[L] + G - YL)/(CHI[L] + CH - TL)  ;
      "END"
   "END" BACKWARD BABUSKA;

   L:= 0; XL:= X[0];
   E1:= E[1]; E2:= E[2]; E3:= E[3]; E4:= E[4]; E5:= E[5]; E6:= E[6];
   "COMMENT" ELEMENTWISE ASSEMBLAGE OF MATRIX AND VECTOR
    COMBINED WITH FORWARD BABUSKA SUBSTITUTION;
   "FOR" L:= L + 1 "WHILE" L <= N "DO"
   "BEGIN" XL1:= XL; L1:= L - 1; XL:= X[L]; H:= XL - XL1;
    "IF" ORDER = 2 "THEN" ELEMENT MAT VEC EVALUATION 1 "ELSE"
    "IF" ORDER = 4 "THEN" ELEMENT MAT VEC EVALUATION 2 "ELSE"
    ELEMENT MAT VEC EVALUATION 3;
    "IF" L=1 "OR" L=N "THEN" BOUNDARY CONDITIONS;
    FORWARD BABUSKA
   "END";
   BACKWARD BABUSKA;
 "END" FEM LAGR;
     "EOP"