eulsum.dem

Delphi Pascal 数据挖掘领域算法包 数值算法大全

PROGRAM d5r1(input,output);
(* driver for routine EULSUM *)
LABEL 10,99;
CONST
   nval=40;
VAR
   i,j,mval,glnterm : integer;
   sum,term,x,xpower : real;
   glwksp : ARRAY [1..nval] OF real;

(*$I MODFILE.PAS *)
(*$I EULSUM.PAS *)

BEGIN
(* evaluate ln(1+x) := x-x^2/2+x^3/3-x^4/4 ... FOR -1<x<1 *)
10:   writeln;
   writeln ('How many terms in polynomial?');
   writeln ('Enter n between 1 and ',nval:2,
            '. (n := 0 to END)');
   readln (mval);
   writeln;
   IF ((mval <= 0) OR (mval > nval)) THEN GOTO 99;
   writeln ('x':9,'actual':14,'polynomial':14);
   FOR i := -8 to 8 DO BEGIN
      x := i/10.0;
      sum := 0.0;
      xpower := -1;
      FOR j := 1 to mval DO BEGIN
         xpower := -x*xpower;
         term := xpower/j;
         eulsum(sum,term,j)
      END;
      writeln (x:12:6,ln(1.0+x):12:6,sum:12:6)
   END;
   GOTO 10;
99:
END.