Minkowski question-mark function: Difference between revisions
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{{
The '''Minkowski question-mark function''' converts the continued fraction representation {{math|[a<sub>0</sub>; a<sub>1</sub>, a<sub>2</sub>, a<sub>3</sub>, ...]}} of a number into a binary decimal representation in which the integer part {{math|a<sub>0</sub>}} is unchanged and the {{math|a<sub>1</sub>, a<sub>2</sub>, ...}} become alternating runs of binary zeroes and ones of those lengths. The decimal point takes the place of the first zero.
Line 21:
Don't worry about precision error in the last few digits.
;See also:
* Wikipedia entry: [[wp:Minkowski%27s_question-mark_function|Minkowski's question-mark function]]
<br><br>
=={{header|11l}}==
{{trans|Python}}
<syntaxhighlight lang="11l">-V MAXITER = 151
F minkowski(x) -> Float
I x > 1 | x < 0
R floor(x) + minkowski(x - floor(x))
V p = Int(x)
V q = 1
V r = p + 1
V s = 1
V d = 1.0
V y = Float(p)
L
d /= 2
I y + d == y
L.break
V m = p + r
I m < 0 | p < 0
L.break
V n = q + s
I n < 0
L.break
I x < Float(m) / n
r = m
s = n
E
y += d
p = m
q = n
R y + d
F minkowski_inv(=x) -> Float
I x > 1 | x < 0
R floor(x) + minkowski_inv(x - floor(x))
I x == 1 | x == 0
R x
V cont_frac = [0]
V current = 0
V count = 1
V i = 0
L
x *= 2
I current == 0
I x < 1
count++
E
cont_frac.append(0)
cont_frac[i] = count
i++
count = 1
current = 1
x--
E
I x > 1
count++
x--
E
cont_frac.append(0)
cont_frac[i] = count
i++
count = 1
current = 0
I x == floor(x)
cont_frac[i] = count
L.break
I i == :MAXITER
L.break
V ret = 1.0 / cont_frac[i]
L(j) (i-1 .. 0).step(-1)
ret = cont_frac[j] + 1.0 / ret
R 1.0 / ret
print(‘#2.16 #2.16’.format(minkowski(0.5 * (1 + sqrt(5))), 5.0 / 3.0))
print(‘#2.16 #2.16’.format(minkowski_inv(-5.0 / 9.0), (sqrt(13) - 7) / 6))
print(‘#2.16 #2.16’.format(minkowski(minkowski_inv(0.718281828)), minkowski_inv(minkowski(0.1213141516171819))))</syntaxhighlight>
{{out}}
<pre>
1.6666666666696983 1.6666666666666667
-0.5657414540893350 -0.5657414540893351
0.7182818280000091 0.1213141516171819
</pre>
=={{header|C#}}==
{{trans|Go}}
<syntaxhighlight lang="C#">
using System;
class Program
{
const int MAXITER = 151;
static double Minkowski(double x)
{
if (x > 1 || x < 0)
{
return Math.Floor(x) + Minkowski(x - Math.Floor(x));
}
ulong p = (ulong)x;
ulong q = 1;
ulong r = p + 1;
ulong s = 1;
double d = 1.0;
double y = (double)p;
while (true)
{
d = d / 2;
if (y + d == y)
{
break;
}
ulong m = p + r;
if (m < 0 || p < 0)
{
break;
}
ulong n = q + s;
if (n < 0)
{
break;
}
if (x < (double)m / (double)n)
{
r = m;
s = n;
}
else
{
y = y + d;
p = m;
q = n;
}
}
return y + d;
}
static double MinkowskiInv(double x)
{
if (x > 1 || x < 0)
{
return Math.Floor(x) + MinkowskiInv(x - Math.Floor(x));
}
if (x == 1 || x == 0)
{
return x;
}
uint[] contFrac = new uint[] { 0 };
uint curr = 0;
uint count = 1;
int i = 0;
while (true)
{
x *= 2;
if (curr == 0)
{
if (x < 1)
{
count++;
}
else
{
i++;
Array.Resize(ref contFrac, i + 1);
contFrac[i - 1] = count;
count = 1;
curr = 1;
x--;
}
}
else
{
if (x > 1)
{
count++;
x--;
}
else
{
i++;
Array.Resize(ref contFrac, i + 1);
contFrac[i - 1] = count;
count = 1;
curr = 0;
}
}
if (x == Math.Floor(x))
{
contFrac[i] = count;
break;
}
if (i == MAXITER)
{
break;
}
}
double ret = 1.0 / contFrac[i];
for (int j = i - 1; j >= 0; j--)
{
ret = contFrac[j] + 1.0 / ret;
}
return 1.0 / ret;
}
static void Main(string[] args)
{
Console.WriteLine("{0,19:0.0000000000000000} {1,19:0.0000000000000000}", Minkowski(0.5 * (1 + Math.Sqrt(5))), 5.0 / 3.0);
Console.WriteLine("{0,19:0.0000000000000000} {1,19:0.0000000000000000}", MinkowskiInv(-5.0 / 9.0), (Math.Sqrt(13) - 7) / 6);
Console.WriteLine("{0,19:0.0000000000000000} {1,19:0.0000000000000000}", Minkowski(MinkowskiInv(0.718281828)),
MinkowskiInv(Minkowski(0.1213141516171819)));
}
}
</syntaxhighlight>
{{out}}
<pre>
1.6666666666697000 1.6666666666666700
-0.5657414540893350 -0.5657414540893350
0.7182818280000090 0.1213141516171820
</pre>
=={{header|C++}}==
<syntaxhighlight lang="c++">
#include <cmath>
#include <cstdint>
#include <iomanip>
#include <iostream>
#include <vector>
constexpr int32_t MAX_ITERATIONS = 151;
double minkowski(const double& x) {
if ( x < 0 || x > 1 ) {
return floor(x) + minkowski(x - floor(x));
}
int64_t p = (int64_t) x;
int64_t q = 1;
int64_t r = p + 1;
int64_t s = 1;
double d = 1.0;
double y = (double) p;
while ( true ) {
d /= 2;
if ( d == 0.0 ) {
break;
}
int64_t m = p + r;
if ( m < 0 || p < 0 ) {
break;
}
int64_t n = q + s;
if ( n < 0 ) {
break;
}
if ( x < (double) m / n ) {
r = m;
s = n;
} else {
y += d;
p = m;
q = n;
}
}
return y + d;
}
double minkowski_inverse(double x) {
if ( x < 0 || x > 1 ) {
return floor(x) + minkowski_inverse(x - floor(x));
}
if ( x == 0 || x == 1 ) {
return x;
}
std::vector<int32_t> continued_fraction(1, 0);
int32_t current = 0;
int32_t count = 1;
int32_t i = 0;
while ( true ) {
x *= 2;
if ( current == 0 ) {
if ( x < 1 ) {
count += 1;
} else {
continued_fraction.emplace_back(0);
continued_fraction[i] = count;
i += 1;
count = 1;
current = 1;
x -= 1;
}
} else {
if ( x > 1 ) {
count += 1;
x -= 1;
} else {
continued_fraction.emplace_back(0);
continued_fraction[i] = count;
i += 1;
count = 1;
current = 0;
}
}
if ( x == floor(x) ) {
continued_fraction[i] = count;
break;
}
if ( i == MAX_ITERATIONS ) {
break;
}
}
double reciprocal = 1.0 / continued_fraction[i];
for ( int32_t j = i - 1; j >= 0; --j ) {
reciprocal = continued_fraction[j] + 1.0 / reciprocal;
}
return 1.0 / reciprocal;
}
int main() {
std::cout << std::setw(20) << std::fixed << std::setprecision(16) << minkowski(0.5 * ( 1 + sqrt(5) ))
<< std::setw(20) << 5.0 / 3.0 << std::endl;
std::cout << std::setw(20) << minkowski_inverse(-5.0 / 9.0)
<< std::setw(20) << ( sqrt(13) - 7 ) / 6 << std::endl;
std::cout << std::setw(20) << minkowski(minkowski_inverse(0.718281828182818))
<< std::setw(20) << 0.718281828182818 << std::endl;
std::cout << std::setw(20) << minkowski_inverse(minkowski(0.1213141516271819))
<< std::setw(20) << 0.1213141516171819 << std::endl;
}
</syntaxhighlight>
{{ out }}
<pre>
1.6666666666696983 1.6666666666666667
-0.5657414540893351 -0.5657414540893352
0.7182818281828269 0.7182818281828180
0.1213141516171819 0.1213141516171819
</pre>
=={{header|F_Sharp|F#}}==
<syntaxhighlight lang="fsharp">
// Minkowski question-mark function. Nigel Galloway: July 14th., 2023
let fN g=let n=(int>>float)g in ((if g<0.0 then -1.0 else 1.0),abs n,abs (g-n))
let fI(n,_,(nl,nh))(g,_,(gl,gh))=let l,h=nl+gl,nh+gh in ((n+g)/2.0,(float l)/(float h),(l,h))
let fG n g=(max n g)-(min n g)
let fE(s,z,l)=Seq.unfold(fun(i,e)->let (n,g,_) as r=fI i e in Some((s*(z+n),s*(g+z)),if l<n then (i,r) else if l=n then (r,r) else (r,e)))((0.0,0.0,(0,1)),(1.0,1.0,(1,1)))
let fL(s,z,l)=Seq.unfold(fun(i,e)->let (n,g,_) as r=fI i e in Some((s*(z+n),s*(g+z)),if l<g then (i,r) else if l=g then (r,r) else (r,e)))((0.0,0.0,(0,1)),(1.0,1.0,(1,1)))
let f2M g=let _,(n,_)=fL(fN g)|>Seq.pairwise|>Seq.find(fun((n,_),(g,_))->(fG n g)<2.328306437e-11) in n
let m2F g=let _,(_,n)=fE(fN g)|>Seq.pairwise|>Seq.find(fun((_,n),(_,g))->(fG n g)<2.328306437e-11) in n
printfn $"?(φ) = 5/3 is %A{fG(f2M 1.61803398874989490253)(5.0/3.0)<2.328306437e-10}"
printfn $"?⁻¹(-5/9) = (√13-7)/6 is %A{fG(m2F(-5.0/9.0))((sqrt(13.0)-7.0)/6.0)<2.328306437e-10}"
let n=42.0/23.0 in printfn $"?⁻¹(?(n)) = n is %A{(fG(m2F(f2M n)) n)<2.328306437e-10}"
let n= -3.0/13.0 in printfn $"?(?⁻¹(n)) = n is %A{(fG(f2M(m2F n)) n)<2.328306437e-10}"
</syntaxhighlight>
{{out}}
<pre>
?(φ) = 5/3 is true
?⁻¹(-5/9) = (√13-7)/6 is true
?⁻¹(?(n)) = n is true
?(?⁻¹(n)) = n is true
</pre>
=={{header|Factor}}==
{{works with|Factor|0.99 2020-08-14}}
<syntaxhighlight lang="factor">USING: formatting kernel make math math.constants
math.continued-fractions math.functions math.parser
math.statistics sequences sequences.extras splitting.monotonic
Line 63 ⟶ 454:
phi ? 5 3 /f compare
-5/9 ?⁻¹ 13 sqrt 7 - 6 /f compare
0.718281828 ?⁻¹ ? 0.1213141516171819 ? ?⁻¹ compare</
{{out}}
<pre>
Line 73 ⟶ 464:
=={{header|FreeBASIC}}==
<
function minkowski( x as double ) as double
Line 144 ⟶ 535:
print minkowski_inv( -5./9 ), (sqr(13)-7)/6
print minkowski(minkowski_inv(0.718281828)), minkowski_inv(minkowski(0.1213141516171819))
</syntaxhighlight>
{{out}}
<pre> 1.666666666669698 1.666666666666667
Line 152 ⟶ 543:
=={{header|Go}}==
{{trans|FreeBASIC}}
<
import (
Line 256 ⟶ 647:
fmt.Printf("%19.16f %19.16f\n", minkowski(minkowskiInv(0.718281828)),
minkowskiInv(minkowski(0.1213141516171819)))
}</
{{out}}
Line 263 ⟶ 654:
-0.5657414540893351 -0.5657414540893352
0.7182818280000092 0.1213141516171819
</pre>
=={{header|Haskell}}==
In a lazy functional language Minkowski question mark function can be implemented using one of it's basic properties:
?(p+r)/(q+s) = 1/2 * ( ?(p/q) + ?(r/s) ), ?(0) = 0, ?(1) = 1.
where p/q and r/s are fractions, such that |ps - rq| = 1.
This recursive definition can be implemented as lazy corecursion, i.e. by generating two infinite binary trees: '''mediant'''-based Stern-Brocot tree, containing all rationals, and '''mean'''-based tree with corresponding values of Minkowsky ?-function. There is one-to-one correspondence between these two trees so both {{math|?(x)}} and {{math|?<sup>-1</sup>(x)}} may be implemented as mapping between them. For details see the paper [[https://habr.com/ru/post/591949/]] (in Russian).
<syntaxhighlight lang="haskell">import Data.Tree
import Data.Ratio
import Data.List
intervalTree :: (a -> a -> a) -> (a, a) -> Tree a
intervalTree node = unfoldTree $
\(a, b) -> let m = node a b in (m, [(a,m), (m,b)])
Node a _ ==> Node b [] = const b
Node a [] ==> Node b _ = const b
Node a [l1, r1] ==> Node b [l2, r2] =
\x -> case x `compare` a of
LT -> (l1 ==> l2) x
EQ -> b
GT -> (r1 ==> r2) x
mirror :: Num a => Tree a -> Tree a
mirror t = Node 0 [reflect (negate <$> t), t]
where
reflect (Node a [l,r]) = Node a [reflect r, reflect l]
------------------------------------------------------------
sternBrocot :: Tree Rational
sternBrocot = toRatio <$> intervalTree mediant ((0,1), (1,0))
where
mediant (p, q) (r, s) = (p + r, q + s)
toRatio (p, q) = p % q
minkowski :: Tree Rational
minkowski = toRatio <$> intervalTree mean ((0,1), (1,0))
mean (p, q) (1, 0) = (p+1, q)
mean (p, q) (r, s) = (p*s + q*r, 2*q*s)
questionMark, invQuestionMark :: Rational -> Rational
questionMark = mirror sternBrocot ==> mirror minkowski
invQuestionMark = mirror minkowski ==> mirror sternBrocot
------------------------------------------------------------
-- Floating point trees and functions
sternBrocotF :: Tree Double
sternBrocotF = mirror $ fromRational <$> sternBrocot
minkowskiF :: Tree Double
minkowskiF = mirror $ intervalTree mean (0, 1/0)
where
mean a b | isInfinite b = a + 1
| otherwise = (a + b) / 2
questionMarkF, invQuestionMarkF :: Double -> Double
questionMarkF = sternBrocotF ==> minkowskiF
invQuestionMarkF = minkowskiF ==> sternBrocotF</syntaxhighlight>
<pre>λ> mapM_ print $ take 4 $ levels farey
[1 % 2]
[1 % 3,2 % 3]
[1 % 4,2 % 5,3 % 5,3 % 4]
[1 % 5,2 % 7,3 % 8,3 % 7,4 % 7,5 % 8,5 % 7,4 % 5]
λ> mapM_ print $ take 4 $ levels minkowski
[1 % 2]
[1 % 4,3 % 4]
[1 % 8,3 % 8,5 % 8,7 % 8]
[1 % 16,3 % 16,5 % 16,7 % 16,9 % 16,11 % 16,13 % 16,15 % 16]</pre>
λ> questionMark (1/2)
1 % 2
λ> questionMark (2/7)
3 % 16
λ> questionMark (-22/7)
(-193) % 64
λ> invQuestionMark (3/16)
2 % 7
λ> invQuestionMark (13/256)
5 % 27</pre>
<pre>λ> questionMark $ (sqrt 5 + 1) / 2
1.6666666666678793
λ> 5/3
1.6666666666666667
λ> invQuestionMark (-5/9)
-0.5657414540893351
λ> (sqrt 13 - 7)/6
-0.5657414540893352</pre>
=={{header|J}}==
Implementation:
<syntaxhighlight lang="j">ITERCOUNT=: 52
minkowski=: {{
f=. 1|y
node=. *i.2 2 NB. node of Stern-Brocot tree
B=. ''
for. i.ITERCOUNT do.
B=. B, b=. f>:%/t=. +/node
node=. t (1-b)} node
end.
(<.y)+B+/ .*2^-1+i.ITERCOUNT
}}
invmink=: {{
f=. 1|y
cf=. i.0
cur=. 0 NB. 1 if generating "top" side of cf
cnt=. 1 NB. proposed continued fraction element
for. i.ITERCOUNT do.
if. f=<. f do.
cf=. cf,%cnt break.
end.
f=. f*2
b=. 1 >`<@.cur f
cf=. cf,(-.b)#cnt
cnt=. 1+b*cnt
cur=. cur=b
f=. f-cur
end.
(+%)/(<.y),cf
}}</syntaxhighlight>
That said, note that this algorithm introduces significant numeric instability for √7 divided by 3:
<syntaxhighlight lang="j"> (minkowski@invmink - invmink@minkowski) (p:%%:)3
1.10713e_6</syntaxhighlight>
I see this same instability using the python implementation and appending:
<syntaxhighlight lang="python"> print(
"{:19.16f} {:19.16f}".format(
minkowski(minkowski_inv(4.04145188432738056)),
minkowski_inv(minkowski(4.04145188432738056)),
)
)</syntaxhighlight>
Using an exact fraction for 4.04145188432738056 and bumping the iteration count from 52 up to 200 changes that difference to 1.43622e_12.
=={{header|Java}}==
<syntaxhighlight lang="java">
import java.util.ArrayList;
import java.util.List;
public final class MinkowskiQuestionMarkFunction {
public static void main(String[] aArgs) {
System.out.println(String.format("%20.16f%20.16f", minkowski(0.5 * ( 1 + Math.sqrt(5) )), 5.0 / 3.0));
System.out.println(String.format("%20.16f%20.16f", minkowskiInverse(-5.0 / 9.0), ( Math.sqrt(13) - 7 ) / 6 ));
System.out.println(String.format("%20.16f%20.16f", minkowski(minkowskiInverse(0.718281828)), 0.718281828));
System.out.println(String.format("%20.16f%20.16f",
minkowskiInverse(minkowski(0.1213141516271819)), 0.1213141516171819));
}
private static double minkowski(double aX) {
if ( aX < 0 || aX > 1 ) {
return Math.floor(aX) + minkowski(aX - Math.floor(aX));
}
long p = (long) aX;
long q = 1;
long r = p + 1;
long s = 1;
double d = 1.0;
double y = (double) p;
while ( true ) {
d /= 2;
if ( d == 0.0 ) {
break;
}
long m = p + r;
if ( m < 0 || p < 0 ) {
break;
}
long n = q + s;
if ( n < 0 ) {
break;
}
if ( aX < (double) m / n ) {
r = m;
s = n;
} else {
y += d;
p = m;
q = n;
}
}
return y + d;
}
private static double minkowskiInverse(double aX) {
if ( aX < 0 || aX > 1 ) {
return Math.floor(aX) + minkowskiInverse(aX - Math.floor(aX));
}
if ( aX == 0 || aX == 1 ) {
return aX;
}
List<Integer> continuedFraction = new ArrayList<Integer>();
continuedFraction.add(0);
int current = 0;
int count = 1;
int i = 0;
while ( true ) {
aX *= 2;
if ( current == 0 ) {
if ( aX < 1 ) {
count += 1;
} else {
continuedFraction.add(0);
continuedFraction.set(i, count);
i += 1;
count = 1;
current = 1;
aX -= 1;
}
} else {
if ( aX > 1 ) {
count += 1;
aX -= 1;
} else {
continuedFraction.add(0);
continuedFraction.set(i, count);
i += 1;
count = 1;
current = 0;
}
}
if ( aX == Math.floor(aX) ) {
continuedFraction.set(i, count);
break;
}
if ( i == MAX_ITERATIONS ) {
break;
}
}
double reciprocal = 1.0 / continuedFraction.get(i);
for ( int j = i - 1; j >= 0; j-- ) {
reciprocal = continuedFraction.get(j) + 1.0 / reciprocal;
}
return 1.0 / reciprocal;
}
private static final int MAX_ITERATIONS = 150;
}
</syntaxhighlight>
{{ out }}
<pre>
1.6666666666696983 1.6666666666666667
-0.5657414540893351 -0.5657414540893352
0.7182818280000092 0.7182818280000000
0.1213141516271825 0.1213141516171819
</pre>
=={{header|Julia}}==
<
y, p =
end
end
function
lo, hi = [0, 1], [1, 1]
while (
bit, bits = fldmod(2bits, 1)
bit > 0 ? (lo .+= hi) : (hi .+= lo)
end
end
x, y = 0.7182818281828, 0.1213141516171819
for (a, b) ∈ [
(5/3, questionmark((1 + √5)/2)),
((√13-7)/6, questionmark_inv(-5/9)),
(x, questionmark_inv(questionmark(x))),
(y, questionmark(questionmark_inv(y)))]
println(a, a ≈ b ? " ≈ " : " != ", b)
end
</syntaxhighlight>{{out}}
<pre>
1.6666666666666667 ≈ 1.666666666667894
-0.5657414540893352 ≈ -0.5657414540893351
0.7182818281828 ≈ 0.7182818281828183
0.1213141516171819 ≈ 0.12131415161718095
</pre>
=={{header|Mathematica}} / {{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">ClearAll[InverseMinkowskiQuestionMark]
InverseMinkowskiQuestionMark[val_] := Module[{x}, (x /. FindRoot[MinkowskiQuestionMark[x] == val, {x, Floor[val], Ceiling[val]}])]
MinkowskiQuestionMark[GoldenRatio]
InverseMinkowskiQuestionMark[-5/9] // RootApproximant
MinkowskiQuestionMark[InverseMinkowskiQuestionMark[0.1213141516171819]]
InverseMinkowskiQuestionMark[MinkowskiQuestionMark[0.1213141516171819]]</syntaxhighlight>
{{out}}
<pre>5/3
1/6 (-7+Sqrt[13])
0.121314
0.121314</pre>
=={{header|Nim}}==
{{trans|Go}}
<syntaxhighlight lang="nim">import math, strformat
const MaxIter = 151
func minkowski(x: float): float =
if x notin 0.0..1.0:
return floor(x) + minkowski(x - floor(x))
var
p = x.uint64
r = p + 1
q, s = 1u64
d = 1.0
y = p.float
while true:
d /= 2
if y + d == y: break
let m = p + r
if m < 0 or p < 0: break
let n = q + s
if n < 0: break
if x < m.float / n.float:
r = m
s = n
else:
y += d
p = m
q = n
result = y + d
func minkowskiInv(x: float): float =
if x notin 0.0..1.0:
return floor(x) + minkowskiInv(x - floor(x))
if x == 1 or x == 0:
return x
var
contFrac: seq[uint32]
curr = 0u32
count = 1u32
i = 0
x = x
while true:
x *= 2
if curr == 0:
if x < 1:
inc count
else:
inc i
contFrac.setLen(i + 1)
contFrac[i - 1] = count
count = 1
curr = 1
x -= 1
else:
if x > 1:
inc count
x -= 1
else:
inc i
contFrac.setLen(i + 1)
contFrac[i - 1] = count
count = 1
curr = 0
if x == floor(x):
contFrac[i] = count
break
if i == MaxIter:
break
var ret = 1 / contFrac[i].float
for j in countdown(i - 1, 0):
ret = contFrac[j].float + 1 / ret
result = 1 / ret
echo &"{minkowski(0.5*(1+sqrt(5.0))):19.16f}, {5/3:19.16f}"
echo &"{minkowskiInv(-5/9):19.16f}, {(sqrt(13.0)-7)/6:19.16f}"
echo &"{minkowski(minkowskiInv(0.718281828)):19.16f}, " &
&"{minkowskiInv(minkowski(0.1213141516171819)):19.16f}"</syntaxhighlight>
{{out}}
<pre> 1.6666666666696983, 1.6666666666666667
-0.5657414540893351, -0.5657414540893352
0.7182818280000092, 0.1213141516171819</pre>
=={{header|Perl}}==
{{trans|Raku}}
<syntaxhighlight lang="perl">use strict;
use warnings;
use feature 'say';
use POSIX qw(floor);
my $MAXITER = 50;
sub minkowski {
my($x) = @_;
return floor($x) + minkowski( $x - floor($x) ) if $x > 1 || $x < 0 ;
my $y = my $p = floor($x);
my ($q,$s,$d) = (1,1,1);
my $r = $p + 1;
while () {
last if ( $y + ($d /= 2) == $y ) or
( my $m = $p + $r) < 0 or
( my $n = $q + $s) < 0;
$x < $m/$n ? ($r,$s) = ($m, $n) : ($y += $d and ($p,$q) = ($m, $n) );
}
return $y + $d
}
sub minkowskiInv {
my($x) = @_;
return floor($x) + minkowskiInv($x - floor($x)) if $x > 1 || $x < 0;
return $x if $x == 1 || $x == 0 ;
my @contFrac = 0;
my $i = my $curr = 0 ; my $count = 1;
while () {
$x *= 2;
if ($curr == 0) {
if ($x < 1) {
$count++
} else {
$i++;
push @contFrac, 0;
$contFrac[$i-1] = $count;
($count,$curr) = (1,1);
$x--;
}
} else {
if ($x > 1) {
$count++;
$x--;
} else {
$i++;
push @contFrac, 0;
@contFrac[$i-1] = $count;
($count,$curr) = (1,0);
}
}
if ($x == floor($x)) { @contFrac[$i] = $count; last }
last if $i == $MAXITER;
}
my $ret = 1 / $contFrac[$i];
for (my $j = $i - 1; $j >= 0; $j--) { $ret = $contFrac[$j] + 1/$ret }
return 1 / $ret
}
printf "%19.16f %19.16f\n", minkowski(0.5*(1 + sqrt(5))), 5/3;
printf "%19.16f %19.16f\n", minkowskiInv(-5/9), (sqrt(13)-7)/6;
printf "%19.16f %19.16f\n", minkowski(minkowskiInv(0.718281828)), minkowskiInv(minkowski(0.1213141516171819));</syntaxhighlight>
{{out}}
<pre> 1.6666666666696983 1.6666666666666667
-0.5657414540893351 -0.5657414540893352
0.7182818280000092 0.1213141516171819</pre>
=={{header|Phix}}==
{{trans|FreeBASIC}}
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">MAXITER</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">151</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">minkowski</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">></span><span style="color: #000000;">1</span> <span style="color: #008080;">or</span> <span style="color: #000000;">x</span><span style="color: #0000FF;"><</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">+</span><span style="color: #000000;">minkowski</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">-</span><span style="color: #000000;">p</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">q</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">d</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">p</span>
<span style="color: #008080;">while</span> <span style="color: #004600;">true</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">d</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">d</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">y</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">d</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">y</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">m</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">r</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">m</span> <span style="color: #0000FF;"><</span> <span style="color: #000000;">0</span> <span style="color: #008080;">or</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;"><</span> <span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">q</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">s</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;"><</span> <span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span> <span style="color: #0000FF;"><</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">/</span><span style="color: #000000;">n</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">m</span>
<span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">y</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">y</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">d</span>
<span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">m</span>
<span style="color: #000000;">q</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">y</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">d</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">minkowski_inv</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">></span><span style="color: #000000;">1</span> <span style="color: #008080;">or</span> <span style="color: #000000;">x</span><span style="color: #0000FF;"><</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">minkowski_inv</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">-</span><span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">))</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">or</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #000000;">x</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">contfrac</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">curr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">count</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">while</span> <span style="color: #004600;">true</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">x</span> <span style="color: #0000FF;">*=</span> <span style="color: #000000;">2</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">curr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span><span style="color: #0000FF;"><</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">count</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">contfrac</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">count</span>
<span style="color: #000000;">count</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
<span style="color: #000000;">curr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
<span style="color: #000000;">x</span> <span style="color: #0000FF;">-=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">else</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">></span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">count</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #000000;">x</span> <span style="color: #0000FF;">-=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">contfrac</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">count</span>
<span style="color: #000000;">count</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
<span style="color: #000000;">curr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">x</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">contfrac</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">count</span>
<span style="color: #008080;">exit</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">contfrac</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">MAXITER</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">ret</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">/</span><span style="color: #000000;">contfrac</span><span style="color: #0000FF;">[$]</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">contfrac</span><span style="color: #0000FF;">)-</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">1</span> <span style="color: #008080;">by</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">ret</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">contfrac</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">1.0</span><span style="color: #0000FF;">/</span><span style="color: #000000;">ret</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">/</span><span style="color: #000000;">ret</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%20.16f %20.16f\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">minkowski</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">*(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">+</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">5</span><span style="color: #0000FF;">))),</span> <span style="color: #000000;">5</span><span style="color: #0000FF;">/</span><span style="color: #000000;">3</span><span style="color: #0000FF;">})</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%20.16f %20.16f\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">minkowski_inv</span><span style="color: #0000FF;">(-</span><span style="color: #000000;">5</span><span style="color: #0000FF;">/</span><span style="color: #000000;">9</span><span style="color: #0000FF;">),</span> <span style="color: #0000FF;">(</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">13</span><span style="color: #0000FF;">)-</span><span style="color: #000000;">7</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">6</span><span style="color: #0000FF;">})</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%20.16f %20.16f\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">minkowski</span><span style="color: #0000FF;">(</span><span style="color: #000000;">minkowski_inv</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.718281828</span><span style="color: #0000FF;">)),</span>
<span style="color: #000000;">minkowski_inv</span><span style="color: #0000FF;">(</span><span style="color: #000000;">minkowski</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.1213141516171819</span><span style="color: #0000FF;">))})</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
1.6666666666696983 1.6666666666666668
-0.5657414540893351 -0.5657414540893352
0.7182818280000092 0.1213141516171819
</pre>
=={{header|Python}}==
{{trans|Go}}
<syntaxhighlight lang="python">import math
MAXITER = 151
def minkowski(x):
if x > 1 or x < 0:
return math.floor(x) + minkowski(x - math.floor(x))
p = int(x)
q = 1
r = p + 1
s = 1
d = 1.0
y = float(p)
while True:
d /= 2
if y + d == y:
break
m = p + r
if m < 0 or p < 0
break
n = q + s
if n < 0
if x < m / n:
r = m
s = n
else:
p = m
q = n
return y + d
if x > 1 or x < 0
cont_frac = [0]
current = 0
count = 1
i = 0
while True:
x *= 2
if current ==
if x < 1:
count += 1
else:
cont_frac[i] = count
i += 1
count = 1
x -= 1
count += 1
x -= 1
else:
cont_frac[i] = count
i += 1
count = 1
for
ret =
return 1.0 / ret
if __name__ == "__main__":
print(
"{:19.16f} {:19.16f}".format(
minkowski(0.5 * (1 + math.sqrt(5))),
5.0 / 3.0,
)
)
print(
"{:19.16f} {:19.16f}".format(
minkowski_inv(-5.0 / 9.0),
(math.sqrt(13) - 7) / 6,
)
)
print(
"{:19.16f} {:19.16f}".format(
minkowski(minkowski_inv(0.718281828)),
minkowski_inv(minkowski(0.1213141516171819)),
)
)
</syntaxhighlight>
{{out}}
<pre>
</pre>
=={{header|Raku}}==
{{trans|Go}}
<syntaxhighlight lang="raku"
my \MAXITER = 151;
Line 485 ⟶ 1,425:
printf "%19.16f %19.16f\n", minkowskiInv(-5/9), (13.sqrt-7)/6;
printf "%19.16f %19.16f\n", minkowski(minkowskiInv(0.718281828)),
minkowskiInv(minkowski(0.1213141516171819))</
{{out}}
<pre> 1.6666666666696983 1.6666666666666667
Line 494 ⟶ 1,434:
{{trans|FreeBASIC}}
{{trans|Phix}}
<
numeric digits
say fmt( mink( 0.5 * (1+sqrt(5) ) ) )
say fmt( minkI(-5/9) ) fmt( (sqrt(13) - 7) / 6)
say fmt( mink( minkI(0.718281828) ) ) fmt( mink( minkI(.1213141516171819) ) )
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
floor: procedure; parse arg x;
fmt: procedure: parse arg
/*──────────────────────────────────────────────────────────────────────────────────────*/
mink: procedure: parse arg x; p= x % 1; if x>1 | x<0 then return p + mink(x-p)
Line 517 ⟶ 1,457:
minkI: procedure; parse arg x; p= floor(x); if x>1 | x<0 then return p + minkI(x-p)
if x=1 | x=0 then return x
#= 1 /*#: is the count. */
do until
if
else do; $= $
else if x>1 then do;
else do; $= $
if x==floor(x)
end /*until*/
z= words($)
return 1 / ret
/*──────────────────────────────────────────────────────────────────────────────────────*/
Line 536 ⟶ 1,475:
numeric form; m.=9; parse value format(x,2,1,,0) 'E0' with g "E" _ .; g=g *.5'e'_ %2
do j=0 while h>9; m.j= h; h= h % 2 + 1; end /*j*/
do k=j+5 to 0 by -1; numeric digits m.k; g= (g + x/g) * .5; end /*k*/; return g</
{{out|output|text= when using the internal default inputs:}}
<pre>
1.66666666666666666666666666673007566392 1.66666666666666666666666666666666666667
-0.56574145408933511781346312208825067563 -0.56574145408933511781346312208825067562
0.71828182799999999999999999999999992890 0.12131415161718190000000000000000000833
</pre>
Line 547 ⟶ 1,486:
{{trans|FreeBASIC}}
{{libheader|Wren-fmt}}
<
var MAXITER = 151
Line 630 ⟶ 1,569:
Fmt.print("$17.14f $17.14f", minkowskiInv.call(-5/9), (13.sqrt - 7)/6)
Fmt.print("$17.14f $17.14f", minkowski.call(minkowskiInv.call(0.718281828)),
minkowskiInv.call(minkowski.call(0.1213141516171819)))</
{{out}}
|