"CODE" 34453; "BOOLEAN" "PROCEDURE" ZEROINDER(X, Y, FX, DFX, TOLX); "REAL" X, Y, FX, DFX, TOLX; "BEGIN" "INTEGER" EXT; "REAL" B, FB, DFB, A, FA, DFA, C, FC, DFC, D, W, MB, TOL, M, P, Q, DW; DW:= DWARF; B:= X; FB:= FX; DFB:= DFX; A:= X:= Y; FA:= FX; DFA:= DFX; INTERPOLATE: C:= A; FC:= FA; DFC:= DFA; EXT:= 0; EXTRAPOLATE: "IF" ABS(FC) < ABS(FB) "THEN" "BEGIN" A:= B; FA:= FB; DFA:= DFB; B:= X:= C; FB:= FC; DFB:= DFC; C:= A; FC:= FA; DFC:= DFA "END" INTERCHANGE; TOL:= TOLX; M:= (C + B) * 0.5; MB:= M - B; "IF" ABS(MB) > TOL "THEN" "BEGIN" "IF" EXT > 2 "THEN" W:= MB "ELSE" "BEGIN" TOL:= TOL * SIGN(MB); D:= "IF" EXT = 2 "THEN" DFA "ELSE" (FB - FA) / (B - A); P:= FB * D * (B - A); Q:= FA * DFB - FB * D; "IF" P < 0 "THEN" "BEGIN" P:= -P; Q:= -Q "END"; W:= "IF" P < DW "OR" P <= Q * TOL "THEN" TOL "ELSE" "IF" P < MB * Q "THEN" P / Q "ELSE" MB; "END"; A:= B; FA:= FB; DFA:= DFB; X:= B:= B + W; FB:= FX; DFB:= DFX; "IF" ("IF" FC >= 0 "THEN" FB >= 0 "ELSE" FB <= 0) "THEN" "GOTO" INTERPOLATE "ELSE" "BEGIN" EXT:= "IF" W = MB "THEN" 0 "ELSE" EXT + 1; "GOTO" EXTRAPOLATE "END" "END"; Y:= C; ZEROINDER:= "IF" FC >= 0 "THEN" FB <= 0 "ELSE" FB >= 0 "END" ZEROINDER; "EOP"