Приветствую !
Вот такой код на Delphi7 ( вычисление корней квадратного уравнения )
| Код |
function Quadratic(const a:double; const b:double; const c:double; var x0, x1: double):integer;
var
t, d: double;
px0:PDouble;
x2:PDouble;
begin
(* degenerated cases *)
if a = 0. then begin
if b = 0. then begin
if c = 0. then begin
Result := -3; Exit;
end;
Result := -2; Exit;
end;
x0 := -c / b;
Result := -1;
Exit;
end;
(* the main case *)
d := b * b - 4. * a * c; // the discriminant
///* one distinct root */
if d = 0. then begin
x1 := -b / (2. * a);
x0 := x1;
Result := 1;
Exit;
end;
(*
* conjugate complex roots - if u need it. Otherwise change this part
*)
if d < 0. then begin
t := 0.5 / a;
x0 := -b * t;
x1 := sqrt(-d) * t;
Result := 0;
Exit;
end;
///* 2 real roots: avoid subtraction of 2 close numbers */
if b >= 0. then begin
d := (-0.5) * (b + sqrt(d));
end else begin
d := (-0.5) * (b - sqrt(d));
end;
x0 := d / a;
x1 := c / d;
Result := 2;
Exit;
end;
procedure TForm3.Button7Click(Sender: TObject);
var
i, j: integer;
//x:array[0..1] of double;
x0, x1: double;
start: dword;
begin
start := GetTickCount();
for i := 0 to 2000000 do begin
Quadratic(1, 4, 3, x0, x1);
end;
ShowMessage(IntToStr(GetTickCount - start));
end;
|
исполняется 250 ms
Вот такой код на Java 1.5 ( Windows XP )
| Код |
/*
* Quadratic equation solution. Real coefficients case.
*
* int Quadratic(double *x,double a,double b,double c); Parameters: x -
* solution array (size 2). On output: 2 real roots -> then x is filled with
* them; 2 complex-conjugate roots -> x[0] is real part, x[1] is
* non-negative imaginary part. other cases -> x[0] unique valid root if
* (-1) returned, no valid roots otherwise. a, b, c - coefficients: ax^2 +
* bx + c = 0. Returns: 2 - 2 real and distince roots; 1 - 1 real distinct
* root (x[0]=x[1]); 0 - 2 complex roots; -1 - one real root in case a==0;
* -2 - no roots in case a=0, b=0; -3 - infinite number of roots (a=b=c=0).
*/
int Quadratic(double x[], double a, double b, double c) {
double d;
/* degenerated cases */
if (a == 0.) {
if (b == 0.) {
if (c == 0.)
return (-3);
return (-2);
}
x[0] = -c / b;
return (-1);
}
/* the main case */
d = b * b - 4. * a * c; /* the discriminant */
/* one distinct root */
if (d == 0.) {
x[0] = x[1] = -b / (2. * a);
return (1);
}
/*
* conjugate complex roots - if u need it. Otherwise change this part
*/
if (d < 0.) {
double t = 0.5 / a;
x[0] = -b * t;
x[1] = Math.sqrt(-d) * t;
return (0);
}
/* 2 real roots: avoid subtraction of 2 close numbers */
if (b >= 0.)
d = (-0.5) * (b + Math.sqrt(d));
else
d = (-0.5) * (b - Math.sqrt(d));
x[0] = d / a;
x[1] = c / d;
return (2);
}
public void testSpeed() {
double x[] = new double[2];
long start = System.currentTimeMillis();
for (int i = 0; i < 2000000; i++) {
Quadratic(x, 1, 4, 3);
}
trace(System.currentTimeMillis() - start);
}
|
исполняется 150 ms
Т.е. Java работает почти в два раза быстрее.
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