std::erf
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Déclaré dans l'en-tête <cmath>
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float erf( float arg ); |
(depuis C++11) | |
double erf( double arg ); |
(depuis C++11) | |
long double erf( long double arg ); |
(depuis C++11) | |
double erf( Integral arg ); |
(depuis C++11) | |
Calcule la fonction d'erreur de
arg
.Original:
Computes the fonction d'erreur of
arg
.The text has been machine-translated via Google Translate.
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Sommaire |
[modifier] Paramètres
arg | - | valeur du point flottant
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. |
[modifier] Retourne la valeur
La valeur de la fonction d'erreur de
∫arg
0e-t2
dt .
arg
, c'est 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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[modifier] Exemple
L'exemple suivant, on calcule la probabilité qu'une variable normale est présent dans l'intervalle (x1, x2)
Original:
The following example calculates the probability that a normal variate is on the interval (x1, x2)
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#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"; }
Résultat :
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%
[modifier] Voir aussi
(C++11) |
fonction d'erreur complémentaire 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. (fonction) |
[modifier] Liens externes
Weisstein, Eric W. "Erf." De MathWorld - Une ressource Web Wolfram .
Original:
Weisstein, Eric W. "Erf." From MathWorld--A Wolfram Web Resource.
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