Rosetta Code

Modified random distribution: Difference between revisions

Page Discussion

Modified random distribution (view source)

Revision as of 06:40, 5 January 2024

10,664 bytes added ,  4 months ago
m
→‎{{header|UNIX Shell}}: change loop style
m (→‎{{header|UNIX Shell}}: change loop style)
 
(11 intermediate revisions by 6 users not shown)
Line 215:
0.92..0.96 *******************************************************************
0.96..1.00 ************************************************************************</pre>
 
=={{header|ALGOL 68}}==
{{Trans|Wren|with slightly modified output}}
<syntaxhighlight lang="algol68">
BEGIN # Modified random distribution - translation of the Wren sample #
 
next random; # initialise the random number generator #
 
PROC rng = ( PROC(REAL)REAL modifier )REAL:
BEGIN
REAL r1, r2;
WHILE
r1 := random;
r2 := random;
r2 >= modifier( r1 )
DO SKIP OD;
r1
END # rng # ;
 
PROC modifier = ( REAL x )REAL: 2 * ABS ( 0.5 - x );
 
INT n = 100 000;
INT num bins = 21;
REAL bin size = 1 / num bins;
CHAR hist char = "#";
INT hist char size = 125;
[ 0 : num bins - 1 ]INT bins ; FOR i FROM LWB bins TO UPB bins DO bins[ i ] := 0 OD;
FOR i FROM 0 TO n DO
bins[ ENTIER ( rng( modifier ) / bin size ) ] +:= 1
OD;
 
PROC f2 = ( REAL v )STRING: # formatting routine #
BEGIN
STRING result := fixed( ABS v, 0, 2 );
IF result[ LWB result ] = "." THEN "0" +=: result FI;
IF v < 0 THEN "-" +=: result FI;
result
END # FMT # ;
 
print( ( "Modified random distribution with ", whole( n, 0 ), " samples in range [0, 1):", newline ) );
print( ( " Range Number of samples within that range", newline ) );
FOR i FROM LWB bins TO UPB bins DO
STRING hist = hist char * ROUND ( bins[ i ] / hist char size );
print( ( f2( bin size * i ), " ..< " ) );
print( ( f2( bin size * ( i + 1 ) ), " ", whole( bins[ i ], -5 ), " ", hist, newline ) )
OD
 
END
</syntaxhighlight>
{{out}}
<pre>
Modified random distribution with 100000 samples in range [0, 1):
Range Number of samples within that range
0.00 ..< 0.05 8990 ########################################################################
0.05 ..< 0.10 8043 ################################################################
0.10 ..< 0.14 7265 ##########################################################
0.14 ..< 0.19 6366 ###################################################
0.19 ..< 0.24 5442 ############################################
0.24 ..< 0.29 4631 #####################################
0.29 ..< 0.33 3805 ##############################
0.33 ..< 0.38 2780 ######################
0.38 ..< 0.43 1725 ##############
0.43 ..< 0.48 907 #######
0.48 ..< 0.52 236 ##
0.52 ..< 0.57 915 #######
0.57 ..< 0.62 1778 ##############
0.62 ..< 0.67 2696 ######################
0.67 ..< 0.71 3657 #############################
0.71 ..< 0.76 4539 ####################################
0.76 ..< 0.81 5382 ###########################################
0.81 ..< 0.86 6337 ###################################################
0.86 ..< 0.90 7230 ##########################################################
0.90 ..< 0.95 8173 #################################################################
0.95 ..< 1.00 9104 #########################################################################
</pre>
 
=={{header|C++}}==
<syntaxhighlight lang="c++">
#include <cmath>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <iostream>
#include <random>
#include <string>
#include <vector>
 
std::random_device random;
std::mt19937 generator(random());
std::uniform_real_distribution<double> distribution(0.0F, 1.0F);
 
double modifier(const double& x) {
return ( x < 0.5 ) ? 2 * ( 0.5 - x ) : 2 * ( x - 0.5 );
}
 
double modified_random(const std::function<double(double)>& modify) {
double result = -1.0;
 
while ( result < 0.0 ) {
double random_one = distribution(generator);
double random_two = distribution(generator);
if ( random_two < modify(random_one) ) {
result = random_one;
}
}
return result;
}
 
int main() {
const int32_t sample_size = 100'000;
const int32_t bin_count = 20;
const double bin_size = 1.0 / bin_count;
 
std::vector<int32_t> bins(bin_count, 0);
 
for ( int32_t i = 0; i < sample_size; ++i ) {
double random = modified_random(modifier);
int32_t bin_number = floor(random / bin_size);
bins[bin_number]++;
}
 
std::cout << "Modified random distribution with " << sample_size << " samples in range [0, 1):"
<< std::endl << std::endl;
std::cout << " Range Number of samples within range" << std::endl;
 
const int32_t scale_factor = 125;
for ( float i = 0.0; i < bin_count; ++i ) {
std::string histogram = " " + std::string(bins[i] / scale_factor, '#') + " ";
std::cout << std::fixed << std::setw(4)<< std::setprecision(2) << i / bin_count << " ..< "
<< std::setw(4) << ( i + 1.0 ) / bin_count << histogram << bins[i] << std::endl;
}
}
</syntaxhighlight>
{{ out }}
<pre>
Modified random distribution with 100000 samples in range [0, 1):
 
Range Number of samples within range
0.00 ..< 0.05 ############################################################################ 9581
0.05 ..< 0.10 ##################################################################### 8662
0.10 ..< 0.15 ############################################################ 7516
0.15 ..< 0.20 ################################################### 6405
0.20 ..< 0.25 ############################################ 5595
0.25 ..< 0.30 #################################### 4502
0.30 ..< 0.35 ########################### 3464
0.35 ..< 0.40 ################### 2466
0.40 ..< 0.45 ############ 1525
0.45 ..< 0.50 #### 508
0.50 ..< 0.55 ### 482
0.55 ..< 0.60 ########### 1479
0.60 ..< 0.65 ################### 2494
0.65 ..< 0.70 ########################### 3440
0.70 ..< 0.75 ##################################### 4656
0.75 ..< 0.80 ############################################ 5544
0.80 ..< 0.85 ################################################### 6483
0.85 ..< 0.90 ########################################################### 7411
0.90 ..< 0.95 ################################################################### 8389
0.95 ..< 1.00 ########################################################################### 9398
</pre>
 
=={{header|Factor}}==
Line 347 ⟶ 506:
=={{header|Fōrmulæ}}==
 
{{FormulaeEntry|page=https://formulae.org/?script=examples/Modified_random_distribution}}
Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text. Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation &mdash;i.e. XML, JSON&mdash; they are intended for storage and transfer purposes more than visualization and edition.
 
'''Solution'''
Programs in Fōrmulæ are created/edited online in its [https://formulae.org website], However they run on execution servers. By default remote servers are used, but they are limited in memory and processing power, since they are intended for demonstration and casual use. A local server can be downloaded and installed, it has no limitations (it runs in your own computer). Because of that, example programs can be fully visualized and edited, but some of them will not run if they require a moderate or heavy computation/memory resources, and no local server is being used.
 
The following is the modifier random distribution function. It does not contain the modifier function, it is passed as a lambda expression:
In '''[https://formulae.org/?example=Modified_random_distribution this]''' page you can see the program(s) related to this task and their results.
 
[[File:Fōrmulæ - Modified random distribution 01.png]]
 
The example modifier is the following:
 
[[File:Fōrmulæ - Modified random distribution 02.png]]
 
The following functions groups a list of numbers in the given number of bins, producing the data necessary for a histogram.
 
[[File:Fōrmulæ - Modified random distribution 03.png]]
 
[[File:Fōrmulæ - Modified random distribution 04.png]]
 
[[File:Fōrmulæ - Modified random distribution 05.png]]
 
'''Test case 1. Showing the histogram of 50,000 numbers in 5 bins'''
 
[[File:Fōrmulæ - Modified random distribution 06.png]]
 
[[File:Fōrmulæ - Modified random distribution 07.png]]
 
'''Test case 2. Showing the histogram of 50,000 numbers in 20 bins'''
 
[[File:Fōrmulæ - Modified random distribution 08.png]]
 
[[File:Fōrmulæ - Modified random distribution 09.png]]
 
'''Test case 3. Showing the histogram of 50,000 numbers in 100 bins'''
 
[[File:Fōrmulæ - Modified random distribution 10.png]]
 
[[File:Fōrmulæ - Modified random distribution 11.png]]
 
=={{header|Go}}==
Line 537 ⟶ 728:
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.Collectors;
import java.util.stream.Stream;
 
Line 550 ⟶ 742:
final double binSize = 1.0 / binCount;
List<Integer> bins = Stream.generate( () -> 0 ).limit(binCount).collect(Collectors.toList());
for ( int i = 0; i < sampleSize; i++ ) {
Line 615 ⟶ 807:
0.90 ..< 0.95 ################################################################### 8474
0.95 ..< 1.00 ############################################################################ 9557
</pre>
 
=={{header|javascript}}==
 
<syntaxhighlight lang=javascript>function modifier(x) { return (x < .5 ? -1 : +1)*(2*(x-.5)) }
 
function random(m) {
let random1, random2;
while (true) {
random1 = Math.random();
random2 = Math.random();
if (random2 < m(random1)) {
return random1;
}
}
}
 
const N = 10000;
const bins = 20;
var numbers = [];
for (i=0;i<N;i++) {
let number = random(modifier);
numbers.push(number);
}
 
const delta = 1.0/bins;
var count = 0;
for (ceil=delta; ceil<1.0+delta; ceil+=delta) {
for (n of numbers) {
if ((n < ceil) && (ceil - delta <= n)) {
count++;
}
}
let width = count/N * 80;
let bar = '';
 
for (i = 0; i<width; i++) bar+='#';
console.log(bar);
count = 0;
}</syntaxhighlight>
{{out}}
<pre>########
#######
#######
######
#####
####
###
###
##
#
#
##
###
###
####
#####
######
######
#######
########
</pre>
 
Line 1,175 ⟶ 1,428:
0.933333...1.000000 *************************************** 6092
</pre>
 
=={{header|Rust}}==
<syntaxhighlight lang="rust">use ndhistogram::{Histogram, ndhistogram, axis::Uniform};
use rand::Rng;
 
/// change x in [0.0, 1.0) to a split with minimum probability at 0.5
fn modifier(x: f64) -> f64 {
if x < 0.5 {
return 2.0 * (0.5 - &x);
} else {
return 2.0 * (&x - 0.5);
}
}
 
const WANTED: usize = 20_000;
 
fn main() {
let mut hist = ndhistogram!(Uniform::new(19, -0.0, 1.0));
let mut rng = rand::thread_rng();
for _ in 0.. WANTED {
loop {
let x: f64 = rng.gen::<f64>();
let y: f64 = rng.gen::<f64>();
if y < modifier(x) {
hist.fill(&f64::from(x));
break;
}
}
}
println!("{}", hist);
}
</syntaxhighlight>{{out}}
<pre>
VecHistogram1D(21 bins, sum=20000)
(-inf, -0.00) |
[0.00, 0.05) | #################################################
[0.05, 0.11) | ############################################
[0.11, 0.16) | #######################################
[0.16, 0.21) | ##################################
[0.21, 0.26) | ###########################
[0.26, 0.32) | ######################
[0.32, 0.37) | ################
[0.37, 0.42) | ###########
[0.42, 0.47) | #####
[0.47, 0.53) | #
[0.53, 0.58) | #####
[0.58, 0.63) | ###########
[0.63, 0.68) | ###############
[0.68, 0.74) | ######################
[0.74, 0.79) | ############################
[0.79, 0.84) | #################################
[0.84, 0.89) | ######################################
[0.89, 0.95) | ############################################
[0.95, 1.00) | ##################################################
[1.00, inf) |
</pre>
 
=={{header|UNIX Shell}}==
{{works with|bash}}
<syntaxhighlight lang=bash># NOTE: In bash, RANDOM returns an integer from 0 to 32767 (2**15-1)
random() {
local m="$1"
local -i random1 random2
while true
do
random1=RANDOM
random2=RANDOM
if ((random2 < $("$m" $random1)))
then echo $random1; break
fi
done
}
 
modifier() {
local -i x=$1
echo $((x < 2**14 ? 2**14 - x : x - 2**14 ))
}
 
declare -i N=10000 bins=20
declare -a histogram
for ((i=0;i<N;i++))
do ((histogram[bins*$(random modifier)/2**15]++))
done
 
for ((i=0;i<bins;i++))
do
for ((j=0;j< ${histogram[i]-0}*bins*50/N;j++))
do echo -n '#'
done
echo
done</syntaxhighlight>
{{out}}
<pre>#################################################################################################
################################################################################
############################################################################
###################################################################
#######################################################
###############################################
###################################
##########################
#############
######
#####
###############
##########################
##################################
#############################################
#####################################################
##############################################################
#######################################################################
####################################################################################
################################################################################################</pre>
 
=={{header|Wren}}==
{{libheader|Wren-fmt}}
<syntaxhighlight lang="ecmascriptwren">import "random" for Random
import "./fmt" for Fmt
 
var rgen = Random.new()
Grondilu
1,934

edits

Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/344089...354598"