qsimp.pas

来自「Delphi Pascal 数据挖掘领域算法包 数值算法大全」· PAS 代码 · 共 21 行

PROCEDURE qsimp(a,b: real; VAR s: real);
LABEL 99;
CONST
   eps=1.0e-6;
   jmax=20;
VAR
   j: integer;
   st,ost,os: real;
BEGIN
   ost := -1.0e30;
   os := -1.0e30;
   FOR j := 1 TO jmax DO BEGIN
      trapzd(a,b,st,j);
      s := (4.0*st-ost)/3.0;
      IF (abs(s-os) < eps*abs(os)) THEN GOTO 99;
      os := s;
      ost := st
   END;
   writeln ('pause in QSIMP - too many steps'); readln;
99:   END;