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adamt19937.adb
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-- LOVELACE version 1
-- Copyright JM Alliot
-- 18 May 2006
-- This is a chess engine xboard compatible written in full ADA
-- with some lines of assembly code
-- It is bitboard based and uses extensively ADA representation clauses
-- Endgames are terrible
-- Draws by repetion are not detected correctly
-- The evaluation function is very bad (and very short..)
-- Use at your own risk...
--------------------------------------------------------------------------------
--| A D A M T 1 9 9 3 7 |--
--| |--
--| B o d y |--
--| |--
--| $Revision 1.2 $ |--
--| |--
--| AdaMT19937 Pseudo Random Number Generator version 1.2 |--
--| Copyright 2002, Adrian Hoe, byhoe@greenlime.com. |--
--| |--
--| This is an Ada implementation of improved initialization (2002/1/26) |--
--| revision by Makoto Matsumoto and Takuji Nishimura of `Mersenne Twister' |--
--| random number generator MT19937. The state vector is initialized by an |--
--| array. Makoto Matsumoto and Takuji Nishimura implemented their algorithm |--
--| in C. This is an Ada implementation by Adrian Hoe (byhoe@greenlime.com) |--
--| on Jan 28, 2002. Lexical Integration (M) Sdn Bhd disclaimed all rights |--
--| of Adrian's work. This copyright message header is not to be removed. |--
--| |--
--| Bobby D. Bryant <bdbryant@mail.utexas.edu> of University of Texas, |--
--| Austin has been contributing to this latest revision of AdaMT19937. |--
--| |--
--| This library is free software; you can redistribute it and/or modify it |--
--| under the terms of the GNU Library General Public License as published |--
--| by the Free Software Foundation (either version 2 of the License or, at |--
--| your option, any later version). This library is distributed in the hope |--
--| that it will be useful, but WITHOUT ANY WARRANTY, without even the |--
--| implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |--
--| See the GNU Library General Public License for more details. You should |--
--| have received a copy of the GNU Library General Public License along |--
--| with this library; if not, write to the Free Software Foundation, Inc., |--
--| 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. |--
--| |--
--| As a special exception, if other files instantiate generics from this |--
--| unit, or you link this unit with other files to produce an executable, |--
--| this unit does not by itself cause the resulting executable to be |--
--| covered by the GNU General Public License. This exception does not |--
--| however invalidate any other reasons why the executable file might be |--
--| covered by the GNU Public License. |--
--| |--
--| The code as Adrian received it included the following notice: |--
--| |--
--| Copyright (C) 1997, 2002 Makoto Matsumoto and Takuji Nishimura. When |--
--| you use this, send an e-mail to <matumoto@math.keio.ac.jp> with an |--
--| appropriate reference to your work. |--
--| |--
--| It would be nice to CC: <byhoe@greenlime.com> when you write. |--
--------------------------------------------------------------------------------
with Unchecked_Deallocation;
with Ada.Calendar;
package body AdaMT19937 is
-----------------------------------------------------------------------------
function Magic (S : in Unsigned_32) return Unsigned_32 is
SS : Unsigned_32 := S and 16#1#;
begin
if SS = 1 then
return 16#9908B0DF#;
else
return 0;
end if;
end Magic;
-----------------------------------------------------------------------------
--| Generates random numbers on [0, 0xffffffff]-interval |--
function Random (G : in Generator) return Unsigned_32 is
State : Access_State := G.State'Unrestricted_Access;
S : Unsigned_32;
begin
if State.Condition >= N then
if State.Condition = Invalid then
Reset (G);
end if;
for J in 0 .. (N - M - 1) loop
S := (State.Vector_N (J) and Upper_Mask) or
(State.Vector_N (J + 1) and Lower_Mask);
State.Vector_N (J) := State.Vector_N (J + M) xor
Shift_Right (S, 1) xor Magic (S);
end loop;
for J in 227 .. (N - 2) loop
S := (State.Vector_N (J) and Upper_Mask) or
(State.Vector_N (J + 1) and Lower_Mask);
State.Vector_N (J) := State.Vector_N (J + (M - N)) xor
Shift_Right (S, 1) xor Magic (S);
end loop;
S := (State.Vector_N (N - 1) and Upper_Mask) or
(State.Vector_N (0) and Lower_Mask);
State.Vector_N (N - 1) := State.Vector_N (M - 1) xor
Shift_Right (S, 1) xor Magic (S);
State.Condition := 0;
end if;
-----------------
--| Tempering |--
-----------------
S := State.Vector_N (State.Condition);
State.Condition := State.Condition + 1;
S := S xor Shift_Right (S, 11);
S := S xor (Shift_Left (S, 7) and 16#9D2C5680#);
S := S xor (Shift_Left (S, 15) and 16#EFC60000#);
S := S xor Shift_Right (S, 18);
return S;
end Random;
-----------------------------------------------------------------------------
procedure Init_By_Seed (G : in Generator) is
State : Access_State := G.State'Unrestricted_Access;
begin
State.Vector_N (0) := G.Seed and 16#FFFFFFFF#;
for I in 1 .. N loop
State.Vector_N (I) := (1_812_433_253 *
(State.Vector_N (I - 1) xor
Shift_Right (State.Vector_N (I - 1), 30)) +
Unsigned_32 (I));
State.Vector_N (I) := State.Vector_N (I) and 16#FFFFFFFF#;
State.Condition := I;
end loop;
end Init_By_Seed;
-----------------------------------------------------------------------------
procedure Init_By_Keys (G : in Generator) is
State : Access_State := G.State'Unrestricted_Access;
I : Integer := 1;
J : Integer := 0;
K, L : Integer;
Key_Length : Integer;
begin
Init_By_Seed (G);
if G.Keys /= null then
---------------------------------------------------------------
--| Allow allocation of Keys (0 .. X) and Keys (1 .. X). |--
--| Otherwise both Keys will generate different results |--
--| even though the values of Keys are identical. This is |--
--| because the index of the array is used to generate |--
--| State Vector as in G.Keys (J + K). |--
---------------------------------------------------------------
K := G.Keys'First;
if G.Keys'First = 0 then
Key_Length := G.Keys'Last + 1;
elsif G.Keys'First > 0 then
Key_Length := G.Keys'Last;
end if;
---------------------------------------------------------------
if N > Key_Length then
L := N;
else
L := Key_Length;
end if;
for X in reverse 1 .. L loop
State.Vector_N (I) := (State.Vector_N (I) xor
((State.Vector_N (I - 1) xor
Shift_Right (State.Vector_N (I - 1), 30)) *
1_664_525)) + G.Keys (J + K) + Unsigned_32 (J);
State.Vector_N (I) := State.Vector_N (I) and 16#FFFFFFFF#;
I := I + 1;
J := J + 1;
if I >= N then
State.Vector_N (0) := State.Vector_N (N - 1);
I := 1;
end if;
if J >= Key_Length then
J := 0;
end if;
end loop;
for X in reverse 1 .. N - 1 loop
State.Vector_N (I) := (State.Vector_N (I) xor
((State.Vector_N (I - 1) xor
Shift_Right (State.Vector_N (I - 1), 30)) *
1_566_083_941)) - Unsigned_32 (I);
I := I + 1;
if I >= N then
State.Vector_N (0) := State.Vector_N (N - 1);
I := 1;
end if;
end loop;
State.Vector_N (0) := Upper_Mask;
end if; -- G.Keys /= null
end Init_By_Keys;
-----------------------------------------------------------------------------
--| Restart initial state of generator |--
procedure Restart (G : in Generator) is
begin
Init_By_Keys (G);
end Restart;
-----------------------------------------------------------------------------
--| Restore from other generator |--
procedure Restore (G : in Generator;
From_Gen : in Generator)
is
Gen : Access_Generator := G'Unrestricted_Access;
begin
Gen.all := Generator (From_Gen);
end Restore;
-----------------------------------------------------------------------------
--| Save the state of generator |--
procedure Save (G : in Generator;
To_Gen : out Generator)
is
begin
To_Gen := Generator (G);
end Save;
-----------------------------------------------------------------------------
--| Save the state of generator to string buffer |--
function Save (G : in Generator) return String is
State_Length : Positive := G.State'Size / Standard.Character'Size;
State_Buffer : String (1 .. State_Length);
for State_Buffer use at G.State'Address;
Seed_Length : Positive := G.Seed'Size / Standard.Character'Size;
Seed_Buffer : String (1 .. Seed_Length);
for Seed_Buffer use at G.Seed'Address;
Total_Length : Positive := Gen_Tag'Length + State_Length + Seed_Length;
Keys_Length : Integer := 0;
begin
if G.Keys /= null then
Keys_Length := G.Keys.all'Size / Standard.Character'Size;
Total_Length := Total_Length + Keys_Length;
declare
Keys_Buffer : String (1 .. Positive (Keys_Length));
for Keys_Buffer use at G.Keys.all'Address;
begin
return (Gen_Tag
& "<"
& Integer'Image (Keys_Length)
& ">"
& State_Buffer
& Seed_Buffer
& Keys_Buffer);
end;
else
return (Gen_Tag
& "<"
& Integer'Image (Keys_Length)
& ">"
& State_Buffer
& Seed_Buffer);
end if;
end Save;
-----------------------------------------------------------------------------
--| Reset with time as seed |--
procedure Reset (G : in Generator) is
package Calendar renames Ada.Calendar;
--------------------------------------------------------------
--| The following code in this Reset procedure is adapted |--
--| from GNAT Run-Time Component Package |--
--| Ada.Numerics.Float_Random (a-nuflra.adb). This package |--
--| is originally contributed by Robert Eachus. For more |--
--| copyright statement, please refer to a-nuflra.adb |--
--------------------------------------------------------------
function Square_Mod_N (X, N : Integer_32) return Integer_32 is
Temp : Flt := Flt (X) * Flt (X);
Div : Integer_32 := Integer_32 (Temp / Flt (N));
begin
Div := Integer_32 (Temp - Flt (Div) * Flt (N));
if Div < 0 then
return Div + N;
else
return Div;
end if;
end Square_Mod_N;
K1 : constant := 94_833_359;
K2 : constant := 47_416_679;
Now : constant Calendar.Time := Calendar.Clock;
Time_Seed : Seed_Type;
X1, X2 : Integer_32;
begin
X1 := Integer_32 (Calendar.Year (Now)) * 12 * 31 +
Integer_32 (Calendar.Month (Now)) * 31 +
Integer_32 (Calendar.Day (Now));
X2 := Integer_32 (Calendar.Seconds (Now) * Duration (1000.0));
X1 := 2 + X1 mod (K1 - 3);
X2 := 2 + X2 mod (K2 - 3);
--| Eliminate visible effects of same day starts |--
for J in 1 .. 5 loop
X1 := Square_Mod_N (X1, K1);
X2 := Square_Mod_N (X2, K2);
end loop;
--| Adrian's modification |--
Time_Seed := Unsigned_32 (X1) or Unsigned_32 (X2);
Reset (G, Time_Seed);
end Reset;
-----------------------------------------------------------------------------
--| Reset from other generator|--
procedure Reset (G : in Generator;
From_Gen : in Generator)
is
Gen : Access_Generator := G'Unrestricted_Access;
begin
Gen.all := Generator (From_Gen);
Init_By_Keys (G);
end Reset;
-----------------------------------------------------------------------------
--| Reset with new seed |--
procedure Reset (G : in Generator;
New_Seed : in Seed_Type)
is
Gen : Access_Generator := G'Unrestricted_Access;
begin
Gen.Seed := New_Seed;
Init_By_Keys (G);
end Reset;
-----------------------------------------------------------------------------
procedure Free is new Unchecked_Deallocation (Vector, Access_Vector);
-----------------------------------------------------------------------------
--| By calling the following Reset functions, it is user's responsibility |--
--| to keep track of dynamically allocated Access_Vector to prevent |--
--| dangling memory space. |--
-----------------------------------------------------------------------------
--| Reset with new seed and new keys |--
--| Gen.Keys = null to remove Keys |--
procedure Reset (G : in Generator;
New_Seed : in Seed_Type;
New_Keys : in Access_Vector)
is
Gen : Access_Generator := G'Unrestricted_Access;
begin
Gen.Seed := New_Seed;
Free (Gen.Keys);
Gen.Keys := New_Keys;
Init_By_Keys (G);
end Reset;
-----------------------------------------------------------------------------
--| Reset with new keys |--
--| Gen.Keys = null to remove Keys |--
procedure Reset (G : in Generator;
New_Keys : in Access_Vector)
is
Gen : Access_Generator := G'Unrestricted_Access;
begin
Free (Gen.Keys);
Gen.Keys := New_Keys;
Init_By_Keys (G);
end Reset;
-----------------------------------------------------------------------------
--| Reset with saved Generator in string buffer |--
procedure Reset (G : in Generator;
G_String : in String)
is
Gen : Access_Generator := G'Unrestricted_Access;
State_Length : Positive := G.State'Size / Standard.Character'Size;
State_Buffer : String (1 .. State_Length);
for State_Buffer use at G.State'Address;
Seed_Length : Positive := G.Seed'Size / Standard.Character'Size;
Seed_Buffer : String (1 .. Seed_Length);
for Seed_Buffer use at G.Seed'Address;
Keys_Length : Integer := 0;
Start, Stop : Integer;
begin
--| Sanity check if G_String is saved state of generator |--
if G_String (G_String'First .. G_String'First + Gen_Tag'Length - 1)
/= Gen_Tag then
raise Constraint_Error;
end if;
--| Get the number of keys saved, 0 if no keys |--
--| Skip the tag and "<": |--
Start := G_String'First + Gen_Tag'Length + 1;
Stop := Start;
while G_String (Stop) /= '>' loop
Stop := Stop + 1;
end loop;
Keys_Length := Integer'Value (G_String (Start .. (Stop - 1)));
--| Get State |--
Start := Stop + 1;
declare
Target : String (1 .. State_Length);
for Target use at Gen.State'Address;
begin
Stop := Start + State_Length;
Target := G_String (Start .. Stop - 1);
end;
--| Get Seed |--
Start := Stop;
declare
Target : String (1 .. Seed_Length);
for Target use at Gen.Seed'Address;
begin
Stop := Start + Seed_Length;
Target := G_String ( Start .. Stop - 1);
end;
--| Get Keys |--
Start := Stop;
if Keys_Length > 0 then
declare
Keys : Access_Vector := new Vector (1 .. Keys_Length / 4);
Target : String ( 1 .. Keys_Length);
for Target use at Keys'Address;
begin
Stop := Start + Keys_Length;
Target := G_String (Start .. Stop - 1);
Free (Gen.Keys);
Gen.Keys := Keys;
end;
end if;
end Reset;
-----------------------------------------------------------------------------
end AdaMT19937;