bessy.pas

来自「Delphi Pascal 数据挖掘领域算法包 数值算法大全」· PAS 代码 · 共 19 行

FUNCTION bessy(n: integer; x: real): real;
VAR
   by,bym,byp,tox: real;
   j: integer;
BEGIN
   IF (n < 2) THEN BEGIN
      writeln('pause in BESSY - index n less than 2'); readln
   END;
   tox := 2.0/x;
   by := bessy1(x);
   bym := bessy0(x);
   FOR j := 1 TO n-1 DO BEGIN
      byp := j*tox*by-bym;
      bym := by;
      by := byp
   END;
   bessy := by
END;