mathpaqs_20200214.0.0_c897786f/multi/pi_digits_gmp.adb

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
--  The Computer Language Shootout
--  http://shootout.alioth.debian.org
--  Calculate digits of pi using the
--  Unbounded Spigot Algorithms
--
--  From Pascal code by Vincent Snijders
--  gmp headers by Karl-Michael Schindler
--  Translated by (New) P2Ada v. 17-June-2006

with Ada.Text_IO;                       use Ada.Text_IO;
with Ada.Integer_Text_IO;               use Ada.Integer_Text_IO;
with Ada.Command_Line;                  use Ada.Command_Line;
with Ada.Calendar;                      use Ada.Calendar;

with Interfaces.C;

procedure pi_digits_GMP is

  pragma Suppress(All_Checks);

  package GMP_mini is
    type mp_limb_t is new Interfaces.C.unsigned;
    type mp_ptr is access mp_limb_t;

    type mpz_t is record
      mp_alloc, mp_size : Interfaces.C.int;
      mp_d    : mp_ptr;
    end record;

    procedure mpz_init (Dest: out mpz_t);
    pragma Import(C, mpz_init, "__gmpz_init");

    procedure mpz_init_set_ui (Dest: out mpz_t; Src: in Interfaces.C.unsigned_long);
    pragma Import(C, mpz_init_set_ui, "__gmpz_init_set_ui");

    procedure mpz_mul_ui (Dest: out mpz_t; Src1: in mpz_t; Src2: in Interfaces.C.unsigned_long);
    pragma Import(C, mpz_mul_ui, "__gmpz_mul_ui");

    procedure mpz_mul_si (Dest: out mpz_t; Src1: in mpz_t; Src2: in Interfaces.C.int);
    pragma Import(C, mpz_mul_si, "__gmpz_mul_si");

    procedure mpz_add (Dest: out mpz_t; Src1, Src2: in mpz_t);
    pragma Import(C, mpz_add, "__gmpz_add");

    procedure mpz_tdiv_q (Dest: out mpz_t; Src1, Src2: in mpz_t);
    pragma Import(C, mpz_tdiv_q, "__gmpz_tdiv_q");

    function  mpz_get_ui (Src: in mpz_t) return Interfaces.C.unsigned_long;
    pragma Import(C, mpz_get_ui, "__gmpz_get_ui");

    pragma Linker_Options("-lgmp");

  end GMP_Mini;

  procedure Print_pi_digits(num_digits: Integer) is
    use GMP_mini;

    q,r,s,t: mpz_t; --  Transformation matrix components

    u,v,w: mpz_t;   --  Temporary variables

    k,digit: Interfaces.C.int;
    c,i: Integer;
    line: String(1 ..10);

    function Extract(x: Interfaces.C.Unsigned_long) return Interfaces.C.int is
    begin
      mpz_mul_ui(u, q, x);
      mpz_add(u, u, r);
      mpz_mul_ui(v, s, x);
      mpz_add(v, v, t);
      mpz_tdiv_q(w, u, v);
      return Interfaces.C.int(mpz_get_ui(w));
    end Extract;

    use Interfaces.C;

    function Is_safe return Boolean is
    begin
      return digit = Extract(4);
    end Is_safe;

    procedure Produce is
    begin
      mpz_mul_si(r, r, 10);
      mpz_mul_si(v, t, -10 * digit);
      mpz_add(r, r, v);
      mpz_mul_si(q, q, 10);
    end Produce;

    procedure Consume is
    begin
      k:= k + 1;
      mpz_mul_si(r, r, 2*k+1);
      mpz_mul_si(u, q, 4*k+2);
      mpz_add(r, r, u);
      mpz_mul_si(t, t, 2*k+1);
      mpz_mul_si(v, s, 4*k+2);
      mpz_add(t, t, v);
      mpz_mul_si(s, s, k);
      mpz_mul_si(q, q, k);
    end Consume;

  begin
    k := 0;
    i := 0;
    c := 0;
    mpz_init_set_ui(q, 1);
    mpz_init_set_ui(r, 0);
    mpz_init_set_ui(s, 0);
    mpz_init_set_ui(t, 1);
    mpz_init(u);
    mpz_init(v);
    mpz_init(w);
    while i < num_digits loop
      digit := Extract(3);
      while not Is_safe loop
        Consume;
        digit:= Extract(3);
      end loop;
      Produce;
      c:= c + 1;
      line(c) := Character'Val(Character'Pos('0')+digit);
      i:= i + 1;
      if c = 10 then
        Put(line & ASCII.HT & ':');
        Put(i,0); New_Line;
        c := 0;
      end if;
    end loop;
    if  c/=0 then
      Put(line(1..c));
      for i in c+1..10 loop
        Put(' ');
      end loop;
      Put(ASCII.HT & ':');
      Put(i,0);
      New_Line;
    end if;
  end Print_pi_digits;

  n: Integer;

  t0,t1: Time;
  timing: constant Boolean:= False;

begin
  n:= 2_500;
  if Argument_Count=1 then
    n:= Integer'Value(Argument(1));
  end if;
  if timing then
    t0:= Clock;
  end if;
  Print_pi_digits(n);
  if timing then
    t1:= Clock;
    Put("Time in seconds: " & Duration'Image(t1-t0) & " [press return]");
    Skip_Line;
  end if;
end pi_digits_GMP;