C++ negative_binomial_distribution用法及代碼示例

該函數定義在頭文件中隨機的隨機的。負二項分布是根據負二項式離散分布(也稱為帕斯卡分布)生成整數的隨機數分布，由以下概率質量函數說明。
$P(i|k, p) = \binom{k + i - 1}{i} \cdot p^k \cdot (1 - p)^i$
該值表示在恰好發生 k 次成功之前，一係列獨立的是/否試驗(每次以概率 p 成功)中的失敗次數。
用法:

template( class IntType = int )
class negative_binomial_distribution

模板參數：
整數類型：生成器生成的結果類型。
會員類型
會員類型及定義

result_type	IntType
param_type	成員返回的類型參數

會員職能：公共成員函數

constructor():構造負二項分布
operator():生成隨機數
reset: 重置分配
param: 分布參數
min : 最小值
max : 最大值

分布參數：公共成員函數

k :分布參數k
p :分布參數p

非成員函數：函數模板

運算符<<：插入輸出流
運算符>>：從輸入流中提取
關係運算符：關係運算符

下麵的程序來說明上麵的模板

CPP


// C++ program to illustrate
// negative_binomial_distribution
#include <bits/stdc++.h>
using namespace std;
int main()
{
    // number of experiments
    const int exps = 10000;
    // maximum number of stars to distribute
    const int numberstars = 100;
    // Generator generate numbers based
    // upon a generator function
    default_random_engine generator;
    // Aman watches GOT
    // At each episode, there's a 50%
    // chance that john snow will die
    // after how many time he'll be turned
    // away before watching 4 episodes?
    negative_binomial_distribution<int> distribution(4, 0.5);
    // initializing an array with size 10
    int p[10] = {};
    for (int i = 0; i < exps; ++i) {
        int counting = distribution(generator);
        if (counting < 10)
            ++p[counting];
    }
    cout << "Negative binomial distribution with "
         << "( k = 4, p = 0.5 ) :" << endl;
    // Printing the sequence stored in an array p
    for (int i = 0; i < 10; ++i)
        cout << i << ": " << string(p[i] * numberstars / exps, '*') << endl;
    return 0;
}

輸出：

Negative binomial distribution with ( k = 4, p = 0.5 ) :
0: *****
1: ************
2: ****************
3: ***************
4: *************
5: **********
6: ********
7: *****
8: ***
9: **

以下程序的分布參數為 1 和 20%
方案2：

CPP


// C++ program to illustrate
// negative_binomial_distribution
#include <bits/stdc++.h>
using namespace std;
int main()
{
    // number of experiments
    const int exps = 10000;
    // maximum number of stars to distribute
    const int numberstars = 100;
    // Generator generate numbers based
    // upon a generator function
    default_random_engine generator;
    // Aman watches GOT
    // At each episode, there's a
    // 20% chance that john snow will die
    // after how many time he'll be
    // turned away before watching 1 episodes?
    negative_binomial_distribution<int> distribution(1, 0.2);
    // initializing an array with size 10
    int p[10] = {};
    for (int i = 0; i < exps; ++i) {
        int counting = distribution(generator);
        if (counting < 10)
            ++p[counting];
    }
    cout << "Negative binomial distribution with "
         << "( k = 1, p = 0.2 ) :" << endl;
    // Printing the sequence stored in an array p
    for (int i = 0; i < 10; ++i)
        cout << i << ": " << string(p[i] * numberstars / exps, '*') << endl;
    return 0;
}

輸出：

Negative binomial distribution with ( k = 1, p = 0.2 ) :
0: *******************
1: ***************
2: ************
3: **********
4: ********
5: ******
6: *****
7: ****
8: ***
9: **

相關用法

注：本文由純淨天空篩選整理自AmanSrivastava1大神的英文原創作品 negative_binomial_distribution in C++ with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。