Data update

Task/Modified-random-distribution/Ada/modified-random-distribution.adb

@@ -0,0 +1,115 @@
+with Ada.Text_Io;
+with Ada.Numerics.Float_Random;
+with Ada.Strings.Fixed;
+
+procedure Modified_Distribution is
+
+   Observations : constant := 20_000;
+   Buckets      : constant := 25;
+   Divider      : constant := 12;
+   Char         : constant Character := '*';
+
+   generic
+      with function Modifier (X : Float) return Float;
+   package Generic_Random is
+      function Random return Float;
+   end Generic_Random;
+
+   package body Generic_Random is
+      package Float_Random renames Ada.Numerics.Float_Random;
+      Generator : Float_Random.Generator;
+
+      function Random return Float is
+         Random_1 : Float;
+         Random_2 : Float;
+      begin
+         loop
+            Random_1 := Float_Random.Random (Generator);
+            Random_2 := Float_Random.Random (Generator);
+            if Random_2 < Modifier (Random_1) then
+               return Random_1;
+            end if;
+         end loop;
+      end Random;
+
+   begin
+     Float_Random.Reset (Generator);
+   end Generic_Random;
+
+   generic
+      Buckets : in Positive;
+   package Histograms is
+      type Bucket_Index is new Positive range 1 .. Buckets;
+      Bucket_Width : constant Float := 1.0 / Float (Buckets);
+      procedure Clean;
+      procedure Increment_Bucket (Observation : Float);
+      function Observations_In (Bucket : Bucket_Index) return Natural;
+      function To_Bucket (X : Float) return Bucket_Index;
+      function Range_Image (Bucket : Bucket_Index) return String;
+   end Histograms;
+
+   package body Histograms is
+      Hist : array (Bucket_Index) of Natural := (others => 0);
+
+      procedure Clean is
+      begin
+         Hist := (others => 0);
+      end Clean;
+
+      procedure Increment_Bucket (Observation : Float) is
+         Bin : constant Bucket_Index := To_Bucket (Observation);
+      begin
+         Hist (Bin) := Hist (Bin) + 1;
+      end Increment_Bucket;
+
+      function Observations_In (Bucket : Bucket_Index) return Natural
+      is (Hist (Bucket));
+
+      function To_Bucket (X : Float) return Bucket_Index
+      is (1 + Bucket_Index'Base (Float'Floor (X / Bucket_Width)));
+
+      function Range_Image (Bucket : Bucket_Index) return String is
+         package Float_Io is new Ada.Text_Io.Float_Io (Float);
+         Image : String := "F.FF..L.LL";
+         First : constant Float := Float (Bucket - 1) / Float (Buckets);
+         Last  : constant Float := Float (Bucket - 1 + 1) / Float (Buckets);
+      begin
+         Float_Io.Put (Image (1 .. 4),  First, Exp => 0, Aft => 2);
+         Float_Io.Put (Image (7 .. 10), Last,  Exp => 0, Aft => 2);
+         return Image;
+      end Range_Image;
+
+   begin
+      Clean;
+   end Histograms;
+
+   function Modifier (X : Float) return Float
+   is (if X in Float'First .. 0.5
+       then 2.0 * (0.5 - X)
+       else 2.0 * (X - 0.5));
+
+   package Modified_Random is
+     new Generic_Random (Modifier => Modifier);
+
+   package Histogram_20 is
+     new Histograms (Buckets => Buckets);
+
+   function Column (Height : Natural; Char : Character) return String
+     renames Ada.Strings.Fixed."*";
+
+   use Ada.Text_Io;
+begin
+   for N in 1 .. Observations loop
+      Histogram_20.Increment_Bucket (Modified_Random.Random);
+   end loop;
+
+   Put ("Range      Observations: "); Put (Observations'Image);
+   Put ("  Buckets: "); Put (Buckets'Image);
+   New_Line;
+   for I in Histogram_20.Bucket_Index'Range loop
+      Put (Histogram_20.Range_Image (I));
+      Put (" ");
+      Put (Column (Histogram_20.Observations_In (I) / Divider, Char));
+      New_Line;
+   end loop;
+end Modified_Distribution;

Task/Modified-random-distribution/EasyLang/modified-random-distribution.easy

@@ -19,7 +19,6 @@ nbins = 20
 histsz = 200
 binsz = 1 / nbins
 len bins[] nbins
-arrbase bins[] 0
 #
 for i to n
    rn = rand

Task/Modified-random-distribution/Fortran/modified-random-distribution.f

@@ -0,0 +1,83 @@
+! Modified random distribution
+! tested with Intel ifx (IFX) 2025.2.1 20250806             on Kubuntu 25.10
+!             GNU gfortran (Ubuntu 15.2.0-4ubuntu4)  15.2.0 on Kubuntu 25.10
+!             VSI Fortran x86-64 V8.7-001                   on OpenVMS V9.2-3
+! U.B., March 2026
+!
+program modrand
+implicit none
+integer, parameter :: DP=8                      ! Reals hare Double PRecision here
+integer, parameter :: NMAX=100000               ! Generate that many random numbers
+integer, parameter :: nHist=21                  ! Number of Histogram Channels
+integer, parameter :: histMaxPoint = 80         ! Normalize maximum Histogram count to 80 chars width
+
+real(kind=DP), dimension(0:nHist) :: HLimits    ! the upper limit of each Histogram channel
+integer, dimension(nHist) :: Hist               ! THe histogram channels
+
+integer :: ii, jj,                              ! loop indices
+integer :: mv, nd                               ! maximum count in all histogram channels
+real (kind=DP) :: r                             ! 1 generated random number
+
+call random_seed ()                             ! Initialize random number generator
+
+do ii=0, nHist                                  !Initialize Histogram limits
+  HLimits(ii) = real(ii,DP) / real(nHist, DP)
+enddo
+Hist = 0
+
+do ii=1, NMAX                                   ! Do the generation
+  call modifiedRandom (r)
+  do jj=1, nHist                                ! Find histogram channel
+    if (r .lt. HLimits (jj)) then
+      Hist(jj) = Hist(jj) + 1
+      exit
+    endif
+  end do
+end do
+
+! Display the histogram: Normalize such that maximum count would display as 80 '*'
+mv = maxval(Hist)
+write (*,'("---Range---    Count ")')
+do ii=1, nHist
+  nd = histMaxPoint * real (hist(ii),DP) / real (mv ,DP)    ! Number of stars to show
+  ! Top line
+  write (*,'(F4.2,"...",F4.2,4X,I5,3x)',advance='no')  HLimits(ii-1), HLimits(ii), hist(ii)
+
+  do jj=1,nd
+    write (*,'("*")', advance='no')
+  enddo
+  write (*,*)
+enddo
+write (*,'(/,"Total:", 7x,I7)')   NMAX
+contains
+
+! =======================================================================
+! returns r as modified randum value as described in the task description
+! =======================================================================
+subroutine modifiedRandom (r)
+real(kind=DP), intent(out) :: r
+real (kind=DP) :: r1, r2
+
+r = -1._DP
+do while (r .lt. 0._DP)
+  call random_number (r1)
+  call random_number (r2)
+  if (r2 < modifier(r1)) r = r1
+end do
+end subroutine modifiedRandom
+
+! ======================================================
+! The modifier function as shown in the task description
+! ======================================================
+pure function modifier(x) result (returnvalue)
+real (kind=DP), intent(in) :: x
+real (kind=DP) :: returnvalue
+
+if (x .lt. 0.5_DP) then
+  returnvalue = 2.0_DP*(0.5_DP - x)
+else
+  returnvalue = 2.0_DP*(x - 0.5_DP)
+endif
+end function modifier
+
+end program modrand

Task/Modified-random-distribution/Pluto/modified-random-distribution.pluto

@@ -0,0 +1,32 @@
+require "table2"
+local fmt = require "fmt"
+
+local function rng(modifier)
+    while true do
+        local r1 = math.random()
+        local r2 = math.random()
+        if r2 < modifier(r1) then return r1 end
+    end
+end
+
+local modifier = |x| -> (x < 0.5) ? 2 * (0.5 - x) : 2 * (x - 0.5)
+
+$define N = 100000
+$define NUM_BINS = 20
+$define HIST_CHAR = "■"
+$define HIST_CHAR_SIZE = 125
+
+local bins = table.rep(NUM_BINS, 0)
+local bin_size = 1 / NUM_BINS
+for i = 1, N do
+    local rn = rng(modifier)
+    local bn = rn // bin_size
+    bins[bn + 1] += 1
+end
+
+fmt.print($"Modified random distribution with %,s samples in range [0, 1):\n", N)
+print("    Range           Number of samples within that range")
+for i = 0, NUM_BINS - 1 do
+    local hist = string.rep(HIST_CHAR, math.round(bins[i + 1] / HIST_CHAR_SIZE))
+    fmt.print("%4.2f ..< %4.2f  %s %,s", bin_size * i, bin_size * (i + 1), hist, bins[i + 1])
+end