blob: 7cf48713a6b03cee1103bddffaa40d9a79a2f478 [file] [log] [blame]
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . N U M E R I C S . G E N E R I C _ C O M P L E X _ T Y P E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Numerics.Aux; use Ada.Numerics.Aux;
package body Ada.Numerics.Generic_Complex_Types is
subtype R is Real'Base;
Two_Pi : constant R := R (2.0) * Pi;
Half_Pi : constant R := Pi / R (2.0);
---------
-- "*" --
---------
function "*" (Left, Right : Complex) return Complex is
Scale : constant R := R (R'Machine_Radix) ** ((R'Machine_Emax - 1) / 2);
-- In case of overflow, scale the operands by the largest power of the
-- radix (to avoid rounding error), so that the square of the scale does
-- not overflow itself.
X : R;
Y : R;
begin
X := Left.Re * Right.Re - Left.Im * Right.Im;
Y := Left.Re * Right.Im + Left.Im * Right.Re;
-- If either component overflows, try to scale (skip in fast math mode)
if not Standard'Fast_Math then
-- Note that the test below is written as a negation. This is to
-- account for the fact that X and Y may be NaNs, because both of
-- their operands could overflow. Given that all operations on NaNs
-- return false, the test can only be written thus.
if not (abs (X) <= R'Last) then
X := Scale**2 * ((Left.Re / Scale) * (Right.Re / Scale) -
(Left.Im / Scale) * (Right.Im / Scale));
end if;
if not (abs (Y) <= R'Last) then
Y := Scale**2 * ((Left.Re / Scale) * (Right.Im / Scale)
+ (Left.Im / Scale) * (Right.Re / Scale));
end if;
end if;
return (X, Y);
end "*";
function "*" (Left, Right : Imaginary) return Real'Base is
begin
return -(R (Left) * R (Right));
end "*";
function "*" (Left : Complex; Right : Real'Base) return Complex is
begin
return Complex'(Left.Re * Right, Left.Im * Right);
end "*";
function "*" (Left : Real'Base; Right : Complex) return Complex is
begin
return (Left * Right.Re, Left * Right.Im);
end "*";
function "*" (Left : Complex; Right : Imaginary) return Complex is
begin
return Complex'(-(Left.Im * R (Right)), Left.Re * R (Right));
end "*";
function "*" (Left : Imaginary; Right : Complex) return Complex is
begin
return Complex'(-(R (Left) * Right.Im), R (Left) * Right.Re);
end "*";
function "*" (Left : Imaginary; Right : Real'Base) return Imaginary is
begin
return Left * Imaginary (Right);
end "*";
function "*" (Left : Real'Base; Right : Imaginary) return Imaginary is
begin
return Imaginary (Left * R (Right));
end "*";
----------
-- "**" --
----------
function "**" (Left : Complex; Right : Integer) return Complex is
Result : Complex := (1.0, 0.0);
Factor : Complex := Left;
Exp : Integer := Right;
begin
-- We use the standard logarithmic approach, Exp gets shifted right
-- testing successive low order bits and Factor is the value of the
-- base raised to the next power of 2. For positive exponents we
-- multiply the result by this factor, for negative exponents, we
-- divide by this factor.
if Exp >= 0 then
-- For a positive exponent, if we get a constraint error during
-- this loop, it is an overflow, and the constraint error will
-- simply be passed on to the caller.
while Exp /= 0 loop
if Exp rem 2 /= 0 then
Result := Result * Factor;
end if;
Factor := Factor * Factor;
Exp := Exp / 2;
end loop;
return Result;
else -- Exp < 0 then
-- For the negative exponent case, a constraint error during this
-- calculation happens if Factor gets too large, and the proper
-- response is to return 0.0, since what we essentially have is
-- 1.0 / infinity, and the closest model number will be zero.
begin
while Exp /= 0 loop
if Exp rem 2 /= 0 then
Result := Result * Factor;
end if;
Factor := Factor * Factor;
Exp := Exp / 2;
end loop;
return R'(1.0) / Result;
exception
when Constraint_Error =>
return (0.0, 0.0);
end;
end if;
end "**";
function "**" (Left : Imaginary; Right : Integer) return Complex is
M : constant R := R (Left) ** Right;
begin
case Right mod 4 is
when 0 => return (M, 0.0);
when 1 => return (0.0, M);
when 2 => return (-M, 0.0);
when 3 => return (0.0, -M);
when others => raise Program_Error;
end case;
end "**";
---------
-- "+" --
---------
function "+" (Right : Complex) return Complex is
begin
return Right;
end "+";
function "+" (Left, Right : Complex) return Complex is
begin
return Complex'(Left.Re + Right.Re, Left.Im + Right.Im);
end "+";
function "+" (Right : Imaginary) return Imaginary is
begin
return Right;
end "+";
function "+" (Left, Right : Imaginary) return Imaginary is
begin
return Imaginary (R (Left) + R (Right));
end "+";
function "+" (Left : Complex; Right : Real'Base) return Complex is
begin
return Complex'(Left.Re + Right, Left.Im);
end "+";
function "+" (Left : Real'Base; Right : Complex) return Complex is
begin
return Complex'(Left + Right.Re, Right.Im);
end "+";
function "+" (Left : Complex; Right : Imaginary) return Complex is
begin
return Complex'(Left.Re, Left.Im + R (Right));
end "+";
function "+" (Left : Imaginary; Right : Complex) return Complex is
begin
return Complex'(Right.Re, R (Left) + Right.Im);
end "+";
function "+" (Left : Imaginary; Right : Real'Base) return Complex is
begin
return Complex'(Right, R (Left));
end "+";
function "+" (Left : Real'Base; Right : Imaginary) return Complex is
begin
return Complex'(Left, R (Right));
end "+";
---------
-- "-" --
---------
function "-" (Right : Complex) return Complex is
begin
return (-Right.Re, -Right.Im);
end "-";
function "-" (Left, Right : Complex) return Complex is
begin
return (Left.Re - Right.Re, Left.Im - Right.Im);
end "-";
function "-" (Right : Imaginary) return Imaginary is
begin
return Imaginary (-R (Right));
end "-";
function "-" (Left, Right : Imaginary) return Imaginary is
begin
return Imaginary (R (Left) - R (Right));
end "-";
function "-" (Left : Complex; Right : Real'Base) return Complex is
begin
return Complex'(Left.Re - Right, Left.Im);
end "-";
function "-" (Left : Real'Base; Right : Complex) return Complex is
begin
return Complex'(Left - Right.Re, -Right.Im);
end "-";
function "-" (Left : Complex; Right : Imaginary) return Complex is
begin
return Complex'(Left.Re, Left.Im - R (Right));
end "-";
function "-" (Left : Imaginary; Right : Complex) return Complex is
begin
return Complex'(-Right.Re, R (Left) - Right.Im);
end "-";
function "-" (Left : Imaginary; Right : Real'Base) return Complex is
begin
return Complex'(-Right, R (Left));
end "-";
function "-" (Left : Real'Base; Right : Imaginary) return Complex is
begin
return Complex'(Left, -R (Right));
end "-";
---------
-- "/" --
---------
function "/" (Left, Right : Complex) return Complex is
a : constant R := Left.Re;
b : constant R := Left.Im;
c : constant R := Right.Re;
d : constant R := Right.Im;
begin
if c = 0.0 and then d = 0.0 then
raise Constraint_Error;
else
return Complex'(Re => ((a * c) + (b * d)) / (c ** 2 + d ** 2),
Im => ((b * c) - (a * d)) / (c ** 2 + d ** 2));
end if;
end "/";
function "/" (Left, Right : Imaginary) return Real'Base is
begin
return R (Left) / R (Right);
end "/";
function "/" (Left : Complex; Right : Real'Base) return Complex is
begin
return Complex'(Left.Re / Right, Left.Im / Right);
end "/";
function "/" (Left : Real'Base; Right : Complex) return Complex is
a : constant R := Left;
c : constant R := Right.Re;
d : constant R := Right.Im;
begin
return Complex'(Re => (a * c) / (c ** 2 + d ** 2),
Im => -((a * d) / (c ** 2 + d ** 2)));
end "/";
function "/" (Left : Complex; Right : Imaginary) return Complex is
a : constant R := Left.Re;
b : constant R := Left.Im;
d : constant R := R (Right);
begin
return (b / d, -(a / d));
end "/";
function "/" (Left : Imaginary; Right : Complex) return Complex is
b : constant R := R (Left);
c : constant R := Right.Re;
d : constant R := Right.Im;
begin
return (Re => b * d / (c ** 2 + d ** 2),
Im => b * c / (c ** 2 + d ** 2));
end "/";
function "/" (Left : Imaginary; Right : Real'Base) return Imaginary is
begin
return Imaginary (R (Left) / Right);
end "/";
function "/" (Left : Real'Base; Right : Imaginary) return Imaginary is
begin
return Imaginary (-(Left / R (Right)));
end "/";
---------
-- "<" --
---------
function "<" (Left, Right : Imaginary) return Boolean is
begin
return R (Left) < R (Right);
end "<";
----------
-- "<=" --
----------
function "<=" (Left, Right : Imaginary) return Boolean is
begin
return R (Left) <= R (Right);
end "<=";
---------
-- ">" --
---------
function ">" (Left, Right : Imaginary) return Boolean is
begin
return R (Left) > R (Right);
end ">";
----------
-- ">=" --
----------
function ">=" (Left, Right : Imaginary) return Boolean is
begin
return R (Left) >= R (Right);
end ">=";
-----------
-- "abs" --
-----------
function "abs" (Right : Imaginary) return Real'Base is
begin
return abs R (Right);
end "abs";
--------------
-- Argument --
--------------
function Argument (X : Complex) return Real'Base is
a : constant R := X.Re;
b : constant R := X.Im;
arg : R;
begin
if b = 0.0 then
if a >= 0.0 then
return 0.0;
else
return R'Copy_Sign (Pi, b);
end if;
elsif a = 0.0 then
if b >= 0.0 then
return Half_Pi;
else
return -Half_Pi;
end if;
else
arg := R (Atan (Double (abs (b / a))));
if a > 0.0 then
if b > 0.0 then
return arg;
else -- b < 0.0
return -arg;
end if;
else -- a < 0.0
if b >= 0.0 then
return Pi - arg;
else -- b < 0.0
return -(Pi - arg);
end if;
end if;
end if;
exception
when Constraint_Error =>
if b > 0.0 then
return Half_Pi;
else
return -Half_Pi;
end if;
end Argument;
function Argument (X : Complex; Cycle : Real'Base) return Real'Base is
begin
if Cycle > 0.0 then
return Argument (X) * Cycle / Two_Pi;
else
raise Argument_Error;
end if;
end Argument;
----------------------------
-- Compose_From_Cartesian --
----------------------------
function Compose_From_Cartesian (Re, Im : Real'Base) return Complex is
begin
return (Re, Im);
end Compose_From_Cartesian;
function Compose_From_Cartesian (Re : Real'Base) return Complex is
begin
return (Re, 0.0);
end Compose_From_Cartesian;
function Compose_From_Cartesian (Im : Imaginary) return Complex is
begin
return (0.0, R (Im));
end Compose_From_Cartesian;
------------------------
-- Compose_From_Polar --
------------------------
function Compose_From_Polar (
Modulus, Argument : Real'Base)
return Complex
is
begin
if Modulus = 0.0 then
return (0.0, 0.0);
else
return (Modulus * R (Cos (Double (Argument))),
Modulus * R (Sin (Double (Argument))));
end if;
end Compose_From_Polar;
function Compose_From_Polar (
Modulus, Argument, Cycle : Real'Base)
return Complex
is
Arg : Real'Base;
begin
if Modulus = 0.0 then
return (0.0, 0.0);
elsif Cycle > 0.0 then
if Argument = 0.0 then
return (Modulus, 0.0);
elsif Argument = Cycle / 4.0 then
return (0.0, Modulus);
elsif Argument = Cycle / 2.0 then
return (-Modulus, 0.0);
elsif Argument = 3.0 * Cycle / R (4.0) then
return (0.0, -Modulus);
else
Arg := Two_Pi * Argument / Cycle;
return (Modulus * R (Cos (Double (Arg))),
Modulus * R (Sin (Double (Arg))));
end if;
else
raise Argument_Error;
end if;
end Compose_From_Polar;
---------------
-- Conjugate --
---------------
function Conjugate (X : Complex) return Complex is
begin
return Complex'(X.Re, -X.Im);
end Conjugate;
--------
-- Im --
--------
function Im (X : Complex) return Real'Base is
begin
return X.Im;
end Im;
function Im (X : Imaginary) return Real'Base is
begin
return R (X);
end Im;
-------------
-- Modulus --
-------------
function Modulus (X : Complex) return Real'Base is
Re2, Im2 : R;
begin
begin
Re2 := X.Re ** 2;
-- To compute (a**2 + b**2) ** (0.5) when a**2 may be out of bounds,
-- compute a * (1 + (b/a) **2) ** (0.5). On a machine where the
-- squaring does not raise constraint_error but generates infinity,
-- we can use an explicit comparison to determine whether to use
-- the scaling expression.
-- The scaling expression is computed in double format throughout
-- in order to prevent inaccuracies on machines where not all
-- immediate expressions are rounded, such as PowerPC.
-- ??? same weird test, why not Re2 > R'Last ???
if not (Re2 <= R'Last) then
raise Constraint_Error;
end if;
exception
when Constraint_Error =>
return R (Double (abs (X.Re))
* Sqrt (1.0 + (Double (X.Im) / Double (X.Re)) ** 2));
end;
begin
Im2 := X.Im ** 2;
-- ??? same weird test
if not (Im2 <= R'Last) then
raise Constraint_Error;
end if;
exception
when Constraint_Error =>
return R (Double (abs (X.Im))
* Sqrt (1.0 + (Double (X.Re) / Double (X.Im)) ** 2));
end;
-- Now deal with cases of underflow. If only one of the squares
-- underflows, return the modulus of the other component. If both
-- squares underflow, use scaling as above.
if Re2 = 0.0 then
if X.Re = 0.0 then
return abs (X.Im);
elsif Im2 = 0.0 then
if X.Im = 0.0 then
return abs (X.Re);
else
if abs (X.Re) > abs (X.Im) then
return
R (Double (abs (X.Re))
* Sqrt (1.0 + (Double (X.Im) / Double (X.Re)) ** 2));
else
return
R (Double (abs (X.Im))
* Sqrt (1.0 + (Double (X.Re) / Double (X.Im)) ** 2));
end if;
end if;
else
return abs (X.Im);
end if;
elsif Im2 = 0.0 then
return abs (X.Re);
-- In all other cases, the naive computation will do
else
return R (Sqrt (Double (Re2 + Im2)));
end if;
end Modulus;
--------
-- Re --
--------
function Re (X : Complex) return Real'Base is
begin
return X.Re;
end Re;
------------
-- Set_Im --
------------
procedure Set_Im (X : in out Complex; Im : Real'Base) is
begin
X.Im := Im;
end Set_Im;
procedure Set_Im (X : out Imaginary; Im : Real'Base) is
begin
X := Imaginary (Im);
end Set_Im;
------------
-- Set_Re --
------------
procedure Set_Re (X : in out Complex; Re : Real'Base) is
begin
X.Re := Re;
end Set_Re;
end Ada.Numerics.Generic_Complex_Types;