std::piecewise_linear_distribution

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std::piecewise_linear_distribution
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piecewise_linear_distribution::piecewise_linear_distribution
piecewise_linear_distribution::reset
代
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Generation
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piecewise_linear_distribution::operator()
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piecewise_linear_distribution::param
piecewise_linear_distribution::min
piecewise_linear_distribution::max
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Non-member functions
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Defined in header <random>
template< class RealType = double >
class piecewise_linear_distribution;
 （C++11 起）

std::piecewise_linear_distribution produces random floating-point numbers, which are distributed according to a linear probability density function within each of the several subintervals [b
i, b
i+1). The distribution is such that the probability density at each interval boundary is exactly the predefined value p
i.

The probability density for any b
i≤x<b
i+1 is p
i
b
i+1-x
b
i+1-b
i
+ p
i+1
x-b
i
b
i+1-b
i
, where probability densities at interval boundaries p
k are calculated as w
k/S where S is the sum of all None
1
2
(w
k+w
k+1)(b
k+1−b
k).

The set of interval boundaries b
i and the set of weights at boundaries w
i are the parameters of this distribution.

目录

[编辑] 会员类型

会员类型
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Member type
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 Definition
result_type RealType
param_type
的类型的参数集，未指定
Original:
the type of the parameter set, unspecified
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[编辑] 成员函数
构建新的分配
Original:
constructs new distribution
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（公共成员函数） [edit]
复位内部状态的分布
Original:
resets the internal state of the distribution
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（公共成员函数） [edit]
代
Original:
Generation
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生成下一个随机数的分布
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generates the next random number in the distribution
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（公共成员函数） [edit]
特性
Original:
Characteristics
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获得间隔边界的列表
Original:
obtains the list of interval boundaries
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（公共成员函数） [edit]
获得的列表在间隔边界的概率密度
Original:
obtains the list of probability densities at interval boundaries
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（公共成员函数） [edit]
获取或设置的分布参数对象
Original:
gets or sets the distribution parameter object
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（公共成员函数） [edit]
返回的最低可能产生的价值
Original:
returns the minimum potentially generated value
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（公共成员函数） [edit]
返回的最大潜在价值
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returns the maximum potentially generated value
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（公共成员函数） [edit]

[编辑] 非成员函数
比较两个分布对象
Original:
compares two distribution objects
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（函数） [edit]
执行流输入和输出的伪随机数分布
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performs stream input and output on pseudo-random number distribution
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（函数） [edit]

[编辑] 为例

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>
 
int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
    // increase the probability from 0 to 5
    // remain flat from 5 to 10
    // decrease from 10 to 15 at the same rate
    std::vector<double> i{0, 5, 10, 15};
    std::vector<double> w{0, 1,   1, 0};
    std::piecewise_linear_distribution<> d(i.begin(), i.end(), w.begin());
 
    std::map<int, int> hist;
    for(int n=0; n<10000; ++n) {
        ++hist[d(gen)];
    }
    for(auto p : hist) {
        std::cout << std::setw(2) << p.first << ' ' << std::string(p.second/100,
    }
}

Output: 

0 *
 1 ***
 2 ****
 3 ******
 4 *********
 5 *********
 6 *********
 7 **********
 8 *********
 9 **********
10 *********
11 *******
12 ****
13 ***
14 *
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