"CODE" 34291;
"PROCEDURE" DECSYM2(A,N,TOL,AUX,P,DETAUX);
"VALUE" N;"INTEGER" N;"REAL" TOL;
"ARRAY" A,DETAUX;"INTEGER" "ARRAY" P,AUX;
"BEGIN" "INTEGER" I,J,K,M,IP1,IP2,DUMMY;"BOOLEAN" ONEBYONE,SYM;
    "REAL" DET,S,T,ALPHA,LAMBDA,SIGMA,AII,AIP1,AIP1I;
    AUX[3]:=AUX[4]:=0;SYM:="TRUE";I:=0;
    "FOR" DUMMY:=0 "WHILE" SYM "AND" (I<N) "DO"
    "BEGIN" I:=I+1;J:=I;
      "FOR" M:=0 "WHILE" SYM "AND" (J<N) "DO"
      "BEGIN" J:=J+1;SYM:=SYM "AND" (A[I,J]=A[J,I]) "END";
    "END";
    "IF" SYM "THEN" AUX[2]:=1
        "ELSE" "BEGIN" AUX[2]:=0;"GOTO" ENDDEC "END";
    ALPHA:=(1+SQRT(17))/8;P[N]:=N;I:=1;
    "FOR" DUMMY:=0 "WHILE" I<N "DO"
    "BEGIN" IP1:=I+1;IP2:=I+2;AII:=ABS(A[I,I]);P[I]:=I;
      LAMBDA:=ABS(A[I,IP1]);J:=IP1;
      "FOR" M:=IP2 "STEP" 1 "UNTIL" N "DO"
      "IF" ABS(A[I,M])>LAMBDA "THEN"
      "BEGIN" J:=M;LAMBDA:=ABS(A[I,M]) "END";
      T:=ALPHA*LAMBDA;ONEBYONE:="TRUE";
      "IF" AII<T "THEN"
      "BEGIN" SIGMA:=LAMBDA;
         "FOR" M:=IP1 "STEP" 1 "UNTIL" J-1 "DO"
            "IF" ABS(A[M,J])>SIGMA "THEN" SIGMA:=ABS(A[M,J]);
         "FOR" M:=J+1 "STEP" 1 "UNTIL" N "DO"
            "IF" ABS(A[J,M])>SIGMA "THEN" SIGMA:=ABS(A[J,M]);
         "IF" SIGMA*AII<LAMBDA "THEN"
         "BEGIN" "IF" ALPHA*SIGMA<ABS(A[J,J]) "THEN"
            "BEGIN" ICHROW(J+1,N,I,J,A);ICHROWCOL(IP1,J-1,I,J,A);
               T:=A[I,I];A[I,I]:=A[J,J];A[J,J]:=T;P[I]:=J
            "END"
            "ELSE"
            "BEGIN" "IF" J>IP1 "THEN"
              "BEGIN" ICHROW(J+1,N,IP1,J,A);ICHROWCOL(IP2,J-1,IP1,J,A);
                  T:=A[I,I];A[I,I]:=A[J,J];A[J,J]:=T;
                  T:=A[I,J];A[I,J]:=A[I,IP1];A[I,IP1]:=T
               "END";
               DET:=A[I,I]*A[IP1,IP1]-A[I,IP1]**2;AIP1I:=A[I,IP1]/DET;
               AII:=A[I,I]/DET;AIP1:=A[IP1,IP1]/DET;P[I]:=J;P[IP1]:=0;
               DETAUX[I]:=1;DETAUX[IP1]:=DET;
               "FOR" J:=IP2 "STEP" 1 "UNTIL" N "DO"
               "BEGIN" S:=AIP1I*A[IP1,J]-AIP1*A[I,J];
                  T:=AIP1I*A[I,J]-AII*A[IP1,J];ELMROW(J,N,J,I,A,A,S);
                  ELMROW(J,N,J,IP1,A,A,T);A[I,J]:=S;A[IP1,J]:=T
               "END";
               AUX[3]:=AUX[3]+1;AUX[4]:=AUX[4]+1;I:=IP2;
               ONEBYONE:="FALSE"
            "END"
         "END"
      "END";
      "IF" ONEBYONE "THEN"
      "BEGIN" "IF" TOL<ABS(A[I,I]) "THEN"
         "BEGIN" AII:=A[I,I];DETAUX[I]:=A[I,I];
            "IF" AII>0 "THEN" AUX[3]:=AUX[3]+1 "ELSE" AUX[4]:=AUX[4]+1;
            "FOR" J:=IP1 "STEP" 1 "UNTIL" N "DO"
           "BEGIN" S:=-A[I,J]/AII;ELMROW(J,N,J,I,A,A,S);A[I,J]:=S "END"
         "END";I:=IP1
      "END"
    "END" WHILE I;
    "IF" I=N "THEN"
    "BEGIN" "IF" TOL<ABS(A[N,N]) "THEN"
      "BEGIN" "IF" A[N,N]>0 "THEN" AUX[3]:=AUX[3]+1
              "ELSE" AUX[4]:=AUX[4]+1
      "END";DETAUX[N]:=A[N,N]
    "END";
  ENDDEC:
    AUX[5]:=N-AUX[3]-AUX[4]
"END" DECSYM2;
        "EOP"