"CODE" 34190;
    "COMMENT" MCA 2420;
    "INTEGER" "PROCEDURE" COMVALQRI(A, N, EM, RE, IM); "VALUE" N;
    "INTEGER" N; "ARRAY" A, EM, RE, IM;
    "BEGIN" "INTEGER" I, J, P, Q, MAX, COUNT, N1, P1, P2, IMIN1,
        I1, I2, I3;
        "REAL" DISC, SIGMA, RHO, G1, G2, G3, PSI1, PSI2, AA, E, K,
        S, NORM, MACHTOL2, TOL, W;
        "BOOLEAN" B;

        NORM:= EM[1]; MACHTOL2:= (EM[0] * NORM) ** 2;
        TOL:= EM[2] * NORM; MAX:= EM[4]; COUNT:= 0; W:= 0;
     IN: "FOR" I:= N, I - 1 "WHILE"
        ("IF" I >= 1 "THEN" ABS(A[I + 1,I]) > TOL "ELSE" "FALSE")
        "DO" Q:= I; "IF" Q > 1 "THEN"
        "BEGIN" "IF" ABS(A[Q,Q - 1]) > W "THEN" W:= ABS(A[Q,Q - 1])
        "END";
        "IF" Q >= N - 1 "THEN"
        "BEGIN" N1:= N - 1; "IF" Q = N "THEN"
            "BEGIN" RE[N]:= A[N,N]; IM[N]:= 0; N:= N1 "END"
            "ELSE"
            "BEGIN" SIGMA:= A[N,N] - A[N1,N1];
                RHO:= -A[N,N1] * A[N1,N];
                DISC:= SIGMA ** 2 - 4 * RHO; "IF" DISC > 0 "THEN"
                "BEGIN" DISC:= SQRT(DISC);
                    S:= -2 * RHO / (SIGMA + ("IF" SIGMA >= 0
                    "THEN" DISC "ELSE" -DISC));
                    RE[N]:= A[N,N] + S;
                    RE[N1]:= A[N1,N1] - S; IM[N]:= IM[N1]:= 0
                "END"
                "ELSE"
                "BEGIN" RE[N]:= RE[N1]:= (A[N1,N1] + A[N,N]) / 2;
                    IM[N1]:= SQRT( -DISC) / 2; IM[N]:= -IM[N1]
                "END";
                N:= N - 2
            "END"
        "END"
        "ELSE"
        "BEGIN" COUNT:= COUNT + 1; "IF" COUNT > MAX "THEN"
            "GOTO" OUT; N1:= N - 1;
            SIGMA:= A[N,N] + A[N1,N1] + SQRT(ABS(A[N1,N - 2] * A[N,N1])
            * EM[0]); RHO:= A[N,N] * A[N1,N1] - A[N,N1] * A[N1,N];
            "FOR" I:= N - 1, I - 1 "WHILE"
            ("IF" I - 1 >= Q "THEN" ABS(A[I,I - 1] *
            A[I1,I] * (ABS(A[I,I] + A[I1,I1] - SIGMA) +
            ABS(A[I + 2,I1]))) > ABS(A[I,I] * ((A[I,I] - SIGMA) +
            A[I,I1] * A[I1,I] + RHO)) * TOL
            "ELSE" "FALSE") "DO" P1:= I1:= I; P:= P1 - 1;
            P2:= P + 2;
            "FOR" I:= P "STEP" 1 "UNTIL" N - 1 "DO"
            "BEGIN" IMIN1:= I - 1; I1:= I + 1; I2:= I + 2;
                "IF" I = P "THEN"
                "BEGIN" G1:= A[P,P] * (A[P,P] - SIGMA) + A[P,P1] *
                    A[P1,P] + RHO;
                    G2:= A[P1,P] * (A[P,P] + A[P1,P1] - SIGMA);
                    "IF" P1 <= N1 "THEN"
                    "BEGIN" G3:= A[P1,P] * A[P2,P1]; A[P2,P]:= 0 "END"
                    "ELSE" G3:= 0
                "END"
                "ELSE"
                "BEGIN" G1:= A[I,IMIN1]; G2:= A[I1,IMIN1];
                    G3:= "IF" I2 <= N "THEN" A[I2,IMIN1] "ELSE" 0
                "END";
                K:= "IF" G1 >= 0 "THEN"
                SQRT(G1 ** 2 + G2 ** 2 + G3 ** 2) "ELSE"
                -SQRT(G1 ** 2 + G2 ** 2 + G3 ** 2);
                B:= ABS(K) > MACHTOL2;
                AA:= "IF" B "THEN" G1 / K + 1 "ELSE" 2;
                PSI1:= "IF" B "THEN" G2 / (G1 + K) "ELSE" 0;
                PSI2:= "IF" B "THEN" G3 / (G1 + K) "ELSE" 0;
                "IF" I ^= Q "THEN" A[I,IMIN1]:= "IF" I = P "THEN"
                -A[I,IMIN1] "ELSE" -K;
                "FOR" J:= I "STEP" 1 "UNTIL" N "DO"
                "BEGIN" E:= AA * (A[I,J] + PSI1 * A[I1,J] +
                    ("IF" I2 <= N "THEN" PSI2 * A[I2,J] "ELSE" 0));
                    A[I,J]:= A[I,J] - E; A[I1,J]:= A[I1,J] - PSI1 * E;
                    "IF" I2 <= N "THEN" A[I2,J]:= A[I2,J] - PSI2 * E
                "END";
                "FOR" J:= Q "STEP" 1 "UNTIL"
                ("IF" I2 <= N "THEN" I2 "ELSE" N) "DO"
                "BEGIN" E:= AA * (A[J,I] + PSI1 * A[J,I1] +
                    ("IF" I2 <= N "THEN" PSI2 * A[J,I2] "ELSE" 0));
                    A[J,I]:= A[J,I] - E; A[J,I1]:= A[J,I1] - PSI1 * E;
                    "IF" I2 <= N "THEN" A[J,I2]:= A[J,I2] - PSI2 * E
                "END";
                "IF" I2 <= N1 "THEN"
                "BEGIN" I3:= I + 3; E:= AA * PSI2 * A[I3,I2];
                    A[I3,I]:= -E;
                    A[I3,I1]:= -PSI1 * E;
                    A[I3,I2]:= A[I3,I2] - PSI2 * E
                "END"
            "END"
        "END";
        "IF" N > 0 "THEN" "GOTO" IN;
    OUT: EM[3]:= W; EM[5]:= COUNT; COMVALQRI:= N
    "END" COMVALQRI

        "EOP"