with A83_014_Vector; use A83_014_Vector; -- for Demo
     with ConsAKD       ; use ConsAKD       ; -- for Demo
     with InteAKD       ; use InteAKD       ; -- for Demo
     with FloaAKD       ; use FloaAKD       ; -- for Demo
     with MathAKD       ; use MathAKD       ; -- for Ln and SqRt
     with TextAKD       ; use TextAKD       ; -- for Demo

     package body DOS_017_Random is
     ----------------------------------------------------------------------
     ----------------------------------------------------------------------

     procedure Demo is
     ----------------------------------------------------------------------
       Seed     : Random_Seed_Type;
       Loops    : constant positive := 1_000;
       Exps     : Vector_Type ( 1..Loops );
       Gaus     : Vector_Type ( 1..Loops );
       Vari     : float := 1.0;
       St_Dev   : float;
     begin
       Put_Line ( Copyright );
       Put_Line ( Description );
       New_Line;
       Put ( Loops );
       Put_Line (
	 " random numbers will be generated for each distribution." );
       New_Line;
       Vari := Ask ( "Desired Gaussian variance ", Vari );
       St_Dev := SqRt ( Vari );
       for Index in Exps'range loop
	 Random_Exp ( Exps ( Index ), Seed );
	 Exps ( Index ) := Exps ( Index );
	 Random_Gaussian ( Gaus ( Index ), Seed, St_Dev );
	 Put ( Index );
	 Put ( "  Random_Exp: " );
	 Put ( Exps ( Index ) );
	 Put ( "  Random_Gaussian: " );
	 Put ( Gaus ( Index ) );
	 New_Line;
       end loop;
       Put ( "Random_Exp      ::  Mean: " );
       Put ( Mean ( Exps ) );
       Put ( "  Variance: " );
       Put ( Variance ( Exps ) );
       New_Line;
       Put ( "Random_Gaussian ::  Mean: " );
       Put ( Mean ( Gaus ) );
       Put ( "  Variance: " );
       Put ( Variance ( Gaus ) );
       New_Line;
       New_Line;
       Pause;
     end Demo;

     procedure Random_Exp (
       Random :    out float;
       Seed   : in out Random_Seed_Type ) is
     ----------------------------------------------------------------------
       R : float;
     begin
       Random_1 ( R, Seed );
       Random := -Ln ( R );
     end Random_Exp;

     procedure Random_Gaussian (
       Random             :    out float;
       Seed               : in out Random_Seed_Type;
       Standard_Deviation : in     float := 1.0 ) is
     ----------------------------------------------------------------------
       Fac, R, V1, V2 : float;
       Ran3 : float;
       Temp : float;
     begin
       if Seed.GlISet = 0 then
	 loop
	   Random_1 ( Ran3, Seed );
	   V1 := 2.0 * Ran3 - 1.0;
	   Random_1 ( Ran3, Seed );
	   V2 := 2.0 * Ran3 - 1.0;
	   R := V1 ** 2 + V2 ** 2;
	   exit when R < 1.0;
	 end loop;
	 Fac := SqRt ( -2.0 * Ln ( R ) / R );
	 Seed.GlGSet := V1 * Fac;
	 Temp := V2 * Fac;
	 Seed.GlISet := 1;
       else
	 Temp := Seed.GlGSet;
	 Seed.GlISet := 0;
       end if;
       Random := Standard_Deviation * Temp;
     end Random_Gaussian;

     ----------------------------------------------------------------------
     ----------------------------------------------------------------------
     end DOS_017_Random;