plgndr.dem

Delphi Pascal 数据挖掘领域算法包 数值算法大全

PROGRAM d6r27(input,output,dfile);
(* driver for routine PLGNDR *)
VAR
   fac,val,x : real;
   i,j,m,n,nval : integer;
   txt : string[20];
   dfile : text;

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

BEGIN
   glopen(dfile,'fncval.dat');
   REPEAT readln(dfile,txt) UNTIL (txt = 'Legendre Polynomials');
   readln(dfile,nval);
   writeln(txt);
   writeln('n':4,'m':4,'x':10,'actual':19,'plgndr(n,m,x)':20);
   FOR i := 1 to nval DO BEGIN
      readln(dfile,n,m,x,val);
      fac := 1.0;
      IF (m > 0) THEN BEGIN
         FOR j := n-m+1 to n+m DO BEGIN
            fac := fac*j
         END
      END;
      fac := 2.0*fac/(2.0*n+1.0);
      val := val*sqrt(fac);
      writeln(n:4,m:4,'   ',x:13,'   ',val:13,'   ',plgndr(n,m,x):13)
   END;
   close(dfile)
END.