Data update

Task/Van-der-Corput-sequence/Ada/van-der-corput-sequence.adb

@@ -0,0 +1,27 @@
+with Ada.Text_IO;
+
+procedure Main is
+   package Float_IO is new Ada.Text_IO.Float_IO (Float);
+   function Van_Der_Corput (N : Natural; Base : Positive := 2) return Float is
+      Value    : Natural  := N;
+      Result   : Float    := 0.0;
+      Exponent : Positive := 1;
+   begin
+      while Value > 0 loop
+         Result   := Result +
+                     Float (Value mod Base) / Float (Base ** Exponent);
+         Value    := Value / Base;
+         Exponent := Exponent + 1;
+      end loop;
+      return Result;
+   end Van_Der_Corput;
+begin
+   for Base in 2 .. 5 loop
+      Ada.Text_IO.Put ("Base" & Integer'Image (Base) & ":");
+      for N in 1 .. 10 loop
+         Ada.Text_IO.Put (' ');
+         Float_IO.Put (Item => Van_Der_Corput (N, Base), Exp => 0);
+      end loop;
+      Ada.Text_IO.New_Line;
+   end loop;
+end Main;

Task/Van-der-Corput-sequence/Crystal/van-der-corput-sequence.cr

@@ -0,0 +1,8 @@
+def vdc (n, base=2)
+  str = n.to_s(base).reverse
+  str.to_i(base) / (base ** str.size)
+end
+
+(2..5).each do |base|
+  puts "Base #{base}: " + Array.new(10){|i| vdc(i,base)}.join(", ")
+end

Task/Van-der-Corput-sequence/Euphoria/van-der-corput-sequence.eu

@@ -0,0 +1,20 @@
+function vdc(integer n, atom base)
+    atom vdc, denom, rem
+    vdc = 0
+    denom = 1
+    while n do
+        denom *= base
+        rem = remainder(n,base)
+        n = floor(n/base)
+        vdc += rem / denom
+    end while
+    return vdc
+end function
+
+for i = 2 to 5 do
+    printf(1,"Base %d\n",i)
+    for j = 0 to 9 do
+        printf(1,"%g ",vdc(j,i))
+    end for
+    puts(1,"\n\n")
+end for

Task/Van-der-Corput-sequence/JavaScript/van-der-corput-sequence.js

@@ -0,0 +1,11 @@
+function vdc(n) {
+  const bits = [...n.toString(2)].toReversed();
+  const exps = [...Array(bits.length).keys()].map(x => -x);
+  let res = 0;
+  for (let i = 0; i < bits.length; i++) {
+    res += bits[i] * 2 ** (exps[i] - 1);
+  }
+  return res;
+}
+
+console.log([...Array(10).keys()].map(vdc).join(" "));

Task/Van-der-Corput-sequence/Oberon-07/van-der-corput-sequence.oberon

@@ -0,0 +1,53 @@
+MODULE VanDerCorput; (* show members of the van der Corput sequence     *)
+                     (* in various bases - translated from the C sample *)
+    IMPORT Out;
+
+    (* returns the gcd of a and b *)
+    PROCEDURE gcd( a, b : INTEGER ) : INTEGER;
+        VAR   n, p, q   : INTEGER;
+        BEGIN
+            p := a;
+            q := b;
+            WHILE p # 0 DO n := p; p := q MOD p; q := n END
+        RETURN q
+        END gcd ;
+
+    (* returns the numerator and denominator of the nth member of *)
+    (*         the van der Corput sequence in the specified base  *)
+    PROCEDURE vc( nth, base : INTEGER; VAR n, d : INTEGER );
+        VAR   p, q, g       : INTEGER;
+        BEGIN
+            p := 0; q := 1; n := nth;
+            WHILE n # 0 DO
+                p := p * base;
+                INC( p, n MOD base );
+                q := q * base;
+                n := n DIV base
+            END;
+            (* return the numerator and denominator reduced by their gcd *)
+            g := gcd( p, q );
+            n := p DIV g;
+            d := q DIV g
+        END vc;
+
+    PROCEDURE task;
+        VAR   i, b, n, d    : INTEGER;
+        BEGIN
+            FOR b := 2 TO 5 DO
+                Out.String( "base " );Out.Int( b, 0 );Out.String( ":" );
+                FOR i := 0 TO 9 DO
+                    vc( i, b, n, d );
+                    IF n = 0 THEN
+                        Out.String( "  0" )
+                    ELSE
+                        Out.String( "  " );Out.Int( n, 0 );
+                        Out.String( "/"  );Out.Int( d, 0 )
+                    END
+                END;
+                Out.Ln
+            END
+        END task ;
+
+BEGIN
+    task
+END VanDerCorput.

Task/Van-der-Corput-sequence/R/van-der-corput-sequence.r

@@ -0,0 +1,12 @@
+num_bits <- function(n) ifelse(log2(n)%%1==0,
+                               1+log2(n),
+                               ceiling(log2(n)))
+
+vdc <- function(n){
+  if(n==0) return(0)
+  inds <- 1:num_bits(n)
+  vdc_raw <- intToBits(n)[inds]
+  sum(as.numeric(vdc_raw)*(2^-inds))
+}
+
+sapply(0:9, vdc)

Task/Van-der-Corput-sequence/VBScript/van-der-corput-sequence.vbs

@@ -0,0 +1,48 @@
+'http://rosettacode.org/wiki/Van_der_Corput_sequence
+'Van der Corput Sequence fucntion call = VanVanDerCorput(number,base)
+
+Base2 = "0" : Base3 = "0" : Base4 = "0" : Base5 = "0"
+Base6 = "0" : Base7 = "0" : Base8 = "0" : Base9 = "0"
+
+l = 1
+h = 1
+Do Until l = 9
+	'Set h to the value of l after each function call
+	'as it sets it to 0 - see lines 37 to 40.
+	Base2 = Base2 & ", " & VanDerCorput(h,2) : h = l
+	Base3 = Base3 & ", " & VanDerCorput(h,3) : h = l
+	Base4 = Base4 & ", " & VanDerCorput(h,4) : h = l
+	Base5 = Base5 & ", " & VanDerCorput(h,5) : h = l
+	Base6 = Base6 & ", " & VanDerCorput(h,6) : h = l
+	l = l + 1
+Loop
+
+WScript.Echo "Base 2: " & Base2
+WScript.Echo "Base 3: " & Base3
+WScript.Echo "Base 4: " & Base4
+WScript.Echo "Base 5: " & Base5
+WScript.Echo "Base 6: " & Base6
+
+'Van der Corput Sequence
+Function VanDerCorput(n,b)
+	k = RevString(Dec2BaseN(n,b))
+	For i = 1 To Len(k)
+		VanDerCorput = VanDerCorput + (CLng(Mid(k,i,1)) * b^-i)
+	Next
+End Function
+
+'Decimal to Base N Conversion
+Function Dec2BaseN(q,c)
+	Dec2BaseN = ""
+	Do Until q = 0
+		Dec2BaseN = CStr(q Mod c) & Dec2BaseN
+		q = Int(q / c)
+	Loop
+End Function
+
+'Reverse String
+Function RevString(s)
+	For j = Len(s) To 1 Step -1
+		RevString = RevString & Mid(s,j,1)
+	Next
+End Function