9000 !***** ROOTER ***** MATHEMATICS PROGRAM *****
9001!***** VERSION #1 ***** 7/31/69 *****
9002!***** UPDATE TO PDP 11/20 ***** 8/8/72
9003 DIM A(26),B(26),X(26)
9004 G8=0:M8=0
9005 &:C1=0:D1=1:O=0
9006 G8=G8+1:&
9007 IF M8=1 THEN PRINT "DO YOU WANT TO CONTINUE":INPUT N$:IF N$="NO" THEN 9999
9009 G8=G8+1:&
9010 PRINT "WHAT IS THE ORDER OF THE POLYNOMIAL":INPUT N
9011 M8=1: IF N=0 THEN 9133
9012 PRINT "ENTER THE COEFFICIENTS, ONE AT A TIME,IN DESCENDING ORDER"
9013 FOR I=1 TO N+1:INPUT A(I):NEXT I
9014 PRINT:PRINT"POLYNOMIAL IS OF ORDER ";N
9015 &:&"       COEFFICIENTS (IN DESCENDING ORDER) ARE:"
9017 &:&"        ";
9019 FOR I=1 TO N+1
9021 &A(I);
9022B(I)=A(I)
9023 NEXT I:&:&
9026 &"   THE ROOT S ARE:"
9028 &:IF N<=2 THEN 9093
9030 IF (N/2-INT(N/2))<1.E-25 THEN 9033
9031 GOSUB 9109
9032 GOTO9028
9033 IF ABS(A(N-1))<1.E-25 THEN 9037
9034 P=A(N)/A(N-1)
9035 Q=A(N+1)/A(N-1)
9036 GOTO9039

9037 P=A(N)
9038 Q=A(N+1)
9039 FOR I=1 TO N+1
9040 X(I)=A(I):NEXT I
9042 GOSUB 9104
9043 FOR I=1 TO N-1
9044B(I)=X(I):NEXT I
9046 R=X(N)
9047 S=A(N+1)-P*X(N)-Q*X(N-1)
9048 GOSUB 9104
9049 X(N)=P*X(N-1)-Q*X(N-2)
9050 D=X(N-1)^2-X(N)*X(N-2)
9051 IF ABS(D)>1.E-25 THEN 9054
9052 &"    SOLUTIONS UNOBTAINABLE IN THIS PROGRAM"
9053 GOTO9005
9054 P1=P+(R*X(N-1)-S*X(N-2))/D
9055 Q1=Q+(S*X(N-1)-R*X(N))/D
9056 IF ABS(P)>1.E-25 THEN 9060
9057 IF ABS(P1)>1.E-25 THEN 9060
9058 IF ABS(Q)>1.E-25 THEN 9061
9059 GOTO 9062
9060 IF ABS(P1/P-1)>.000001 THEN 9062
9061 IF ABS(Q1/Q-1)<.000001 THEN 9076
9062 LET P=P1
9063 LET Q=Q1
9064 LET C1=C1+1
9065 IF C1=D1*25 THEN 9067
9066 GOTO 9039
9067 PRINT
9068 PRINT "THE SOLUTION DID NOT CONVERGE AFTER";C1;"ITERATIONS TO"
9069 PRINT "CONTINUE THE SOLUTION FOR 25 MORE ITERATIONS TYPE 1 OTHERWISE"
9070 PRINT "TYPE 0."
9071 INPUT K1
9072 IF K1=1 THEN9074
9073 GOTO 9005
9074 LET D1=D1+1
9075 GOTO 9039
9076 FOR I=2 TO N-1
9077 LET A(I)=B(I)
9078 NEXT I
9079 LET N=N-2
9080 LET D=P*P-4*Q
9081 IF D<0 THEN 9088
9082 LET D=SQR(D)
9083 PRINT"        ";(-P+D)/2;"  AND  ";(-P-D)/2
9084 LET C1=0
9085 LET D1=1
9086 IF N-2>0 THEN 9029
9087 GOTO 9093
9088 LET D=SQR(-D)
9089 PRINT"        ";-P/2;" + J *";D/2"  AND  ";-P/2;" - J *";D/2
9090 LET C1=0
9091 LET D1=1
9092 IF N-2>0 THEN 9029
9093 IF N=1 THEN 9099
9094 IF N=0 THEN 9005
9095 LET P=B(2)/B(1)
9096 LET Q=B(3)/B(1)
9097 LET N=0
9098 GOTO 9080
9099 PRINT "      ";-B(2)/B(1)
9100 GOTO 9005
9101 PRINT "       0.00000"
9102 LET N=N-1
9103 GOTO 9028
9104 LET X(2)=X(2)-P*X(1)
9105 FOR I=3 TO N
9106 X(I)=X(I)-P*X(I-1)-Q*X(I-2)
9107 NEXT I
9108 RETURN
9109 IF B(2)=0 THEN 9112
9110 LET X=-B(2)/B(1)
9111 GOTO 9113
9112 LET X=-B(N+1)/B(1)
9113 LET F=0
9114 LET F1=0
9115 FOR I=1 TO N+1
9116 LET J=N-I+2
9117 IF B(J)=0 THEN 9121
9118 LET F=B(J)*X^(I-1)+F
9119 IF I-1=O THEN 9121
9120 LET F1=(I-1)*B(J)*X^(I-2)+F1
9121 NEXT I
9122 LET X1=X-F/F1
9123 IF ABS(X/X1-1)<.000001 THEN 9126
9124 LET X=X1
9125 GOTO 9113
9126 PRINT "      ";X1
9127 LET N=N-1
9128 FOR I=2 TO N+1
9129 LET A(I)=B(I)+X1*A(I-1)
9130 LET B(I)=A(I)
9131 NEXT I
9132 RETURN
9133 GOTO9999
9999 END