d2r8.txt

《Delphi常用数值算法集》的配书源码

implementation
//PROGRAM D2R8
//Driver for routine POLCOF
uses
  unit2;
  {$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
var
  XA,YA,COEFF:array[0..5] of real;
  X,FF,SUM:real;
  F:TextFile;  I,J,NFUNC:Integer;
const
  NP=5; PI=3.1415926; s1='%16.6f'; s2='%12.6f';
begin
  //输出计算结果到文件
  AssignFile(F, 'd:\delphi_shu\p2\d2r8.dat');
  Rewrite(F);
  For NFUNC:=1 To 2 do
    begin
      If NFUNC = 1 Then
        begin
          Writeln(F,'Sine function from 0 to PI');
          For I:=1 To NP do
            begin
              XA[I]:=I * PI / NP;
              YA[I]:=Sin(XA[I]);
            end;
        end
      else
        begin
          Writeln(F,'****************************************');
          Writeln(F,'Exponential function from 0 to 1');
          For I:=1 To NP do
            begin
              XA[I]:=I / NP;
              YA[I]:=Exp(XA[I]);
            end;
        end;
      POLCOF(XA,YA,NP,COEFF);
      Writeln(F,'  corfficients');
      Writeln(F,Format(s2,[coeff[1]]),Format(s2,[coeff[2]]),
       Format(s2,[coeff[3]]),Format(s2,[coeff[4]]),Format(s2,[coeff[5]]));
      Writeln(F,'            x             f(x)         polynomial');
      For I:=1 To 10 do
        BEGIN
          If NFUNC = 1 Then
            begin
              X:=(-0.05 + I / 10) * PI;
              FF:=Sin(X);
            end
          else
            begin
              X:=(-0.05 + I / 10);
              FF:=Exp(X);
            end;
          SUM:= COEFF[NP];
          FOR J:=NP-1 DownTo 1 do
            SUM:= COEFF[J] + SUM * X;
          Writeln(F,Format(s1,[X]),Format(s1,[FF]),Format(s1,[SUM]));
        END;
      END;
    Writeln(F,'****************************************');
  CloseFile(F);
  //屏幕显示计算结果
  memo1.ScrollBars:=ssVertical;
  memo1.Lines.LoadFromFile('d:\delphi_shu\p2\d2r8.dat');
end;