Difference between revisions of "cpp/numeric/random/lognormal distribution"
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m (use mathjax-or for sometimes math is badly rendered) |
Andreas Krug (Talk | contribs) m (., headers sorted) |
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{{cpp/title|lognormal_distribution}} | {{cpp/title|lognormal_distribution}} | ||
{{cpp/numeric/random/lognormal_distribution/navbar}} | {{cpp/numeric/random/lognormal_distribution/navbar}} | ||
| − | {{ddcl | header=random | since=c++11 | 1= | + | {{ddcl|header=random|since=c++11|1= |
template< class RealType = double > | template< class RealType = double > | ||
class lognormal_distribution; | class lognormal_distribution; | ||
}} | }} | ||
| − | The lognormal_distribution random number distribution produces random numbers {{math|x > 0}} according to a | + | The lognormal_distribution random number distribution produces random numbers {{math|x > 0}} according to a enwikiLog-normal distribution: |
| − | :{{mathjax-or|1=\({\small f(x;m,s) = \frac{1}{sx\sqrt{2\pi} } \exp{(-\frac{ {(\ln{x} - m)}^{2} }{2{s}^{2} })} }\)|2=f(x; m,s) = {{mfrac||1|sx{{mrad|2 π}} }} exp{{mparen|(|)|- {{mfrac||(ln x - m){{su|p=2}}| 2s{{su|p=2}}}} }} }} | + | :{{mathjax-or|1=\({\small f(x;m,s) = \frac{1}{sx\sqrt{2\pi} } \exp{(-\frac{ {(\ln{x} - m)}^{2} }{2{s}^{2} })} }\)|2=f(x; m,s) = {{mfrac||1|sx{{mrad|2 π}}}} exp{{mparen|(|)|- {{mfrac||(ln x - m){{su|p=2}}|2s{{su|p=2}}}}}}}} |
The parameters {{math|m}} and {{math|s}} are, respectively, the mean and standard deviation of the natural logarithm of {{math|x}}. | The parameters {{math|m}} and {{math|s}} are, respectively, the mean and standard deviation of the natural logarithm of {{math|x}}. | ||
| − | {{ | + | {{|std::lognormal_distribution}} satisfies all requirements of {{named req|RandomNumberDistribution}} |
===Template parameters=== | ===Template parameters=== | ||
| Line 21: | Line 21: | ||
===Member types=== | ===Member types=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc hitem | Member type | Definition}} | + | {{dsc hitem|Member type|Definition}} |
| − | {{dsc | {{tt|result_type}} | + | {{dsc|{{tt|result_type}} {{c|RealType}}}} |
{{cpp/numeric/random/param_type}} | {{cpp/numeric/random/param_type}} | ||
{{dsc end}} | {{dsc end}} | ||
| Line 28: | Line 28: | ||
===Member functions=== | ===Member functions=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/numeric/random/distribution/dsc constructor | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc constructor|lognormal_distribution}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc reset | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc reset|lognormal_distribution}} |
| − | {{dsc h2 | Generation}} | + | {{dsc h2|Generation}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc operator() | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc operator()|lognormal_distribution}} |
| − | {{dsc h2 | Characteristics}} | + | {{dsc h2|Characteristics}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc params | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc params|lognormal_distribution}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc param | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc param|lognormal_distribution}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc min | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc min|lognormal_distribution}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc max | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc max|lognormal_distribution}} |
{{dsc end}} | {{dsc end}} | ||
===Non-member functions=== | ===Non-member functions=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/numeric/random/distribution/dsc operator_cmp | lognormal_distribution }} | + | {{dsc inc|cpp/numeric/random/distribution/dsc operator_cmp|lognormal_distribution}} |
| − | {{dsc inc | cpp/numeric/random/distribution/dsc operator_ltltgtgt | lognormal_distribution}} | + | {{dsc inc|cpp/numeric/random/distribution/dsc operator_ltltgtgt|lognormal_distribution}} |
{{dsc end}} | {{dsc end}} | ||
===Example=== | ===Example=== | ||
{{example | {{example | ||
| − | + | |code= | |
| − | #include < | + | #include <> |
#include <iomanip> | #include <iomanip> | ||
| − | #include < | + | #include <> |
#include <map> | #include <map> | ||
#include <random> | #include <random> | ||
| − | #include < | + | #include <> |
| + | |||
int main() | int main() | ||
{ | { | ||
| Line 64: | Line 65: | ||
std::map<int, int> hist; | std::map<int, int> hist; | ||
| − | for(int n=0; n< | + | for (int n = 0; n < ; ++n) |
++hist[std::round(d(gen))]; | ++hist[std::round(d(gen))]; | ||
| − | + | ||
| − | for( | + | for (std::cout << std::fixed << std::setprecision(1) |
| − | + | << std::<< << ' ' << std::string(/ 200, '*') << '\n'; | |
| − | + | ||
| − | + | ||
} | } | ||
| − | + | |p=true | |
| − | + | |output= | |
| − | + | 2 | |
| − | + | 3 *** | |
| − | + | 4 ************* | |
| − | + | 5 *************** | |
| − | + | 6 ********* | |
| − | + | 7 **** | |
| − | + | 8 * | |
| − | + | 9 | |
| − | + | ||
| − | + | ||
| − | + | ||
}} | }} | ||
===External links=== | ===External links=== | ||
| − | + | [://mathworld.wolfram.com/LogNormalDistribution.html Weisstein, Eric W. "Log Normal Distribution."] From MathWorld A Wolfram Web Resource. | |
{{langlinks|de|es|fr|it|ja|pt|ru|zh}} | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||