std::erf
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Definido no cabeçalho <cmath>
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float erf( float arg ); |
(desde C++11) | |
double erf( double arg ); |
(desde C++11) | |
long double erf( long double arg ); |
(desde C++11) | |
double erf( Integral arg ); |
(desde C++11) | |
Calcula a função de erro de
arg
.Original:
Computes the função de erro of
arg
.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Índice |
[editar] Parâmetros
arg | - | flutuando valor de ponto
Original: floating point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
[editar] Valor de retorno
O valor da função de erro de
∫arg
0e-t2
dt.
arg
, isto é 2 |
√π |
0e-t2
dt.
Original:
The value of the error function of
∫arg
0e-t2
dt.
arg
, that is 2 |
√π |
0e-t2
dt.
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[editar] Exemplo
The following example calculates the probability that a normal variate is on the interval (x1, x2)
#include <iostream> #include <cmath> #include <iomanip> double phi(double x1, double x2) { return (std::erf(x2/std::sqrt(2)) - std::erf(x1/std::sqrt(2)))/2; } int main() { std::cout << "normal variate probabilities:\n"; for(int n=-4; n<4; ++n) std::cout << "[" << std::setw(2) << n << ":" << std::setw(2) << n+1 << "]: " << std::setw(5) << std::fixed << std::setprecision(2) << 100*phi(n, n+1) << "%\n"; }
Saída:
normal variate probabilities: [-4:-3]: 0.13% [-3:-2]: 2.14% [-2:-1]: 13.59% [-1: 0]: 34.13% [ 0: 1]: 34.13% [ 1: 2]: 13.59% [ 2: 3]: 2.14% [ 3: 4]: 0.13%
[editar] Veja também
(C++11) |
função de erro complementar Original: complementary error function The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função) |
[editar] Links externos
Weisstein, Eric W. "Erf." De MathWorld - Um recurso Web Wolfram.
Original:
Weisstein, Eric W. "Erf." From MathWorld--A Wolfram Web Resource.
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