28 Numerics library [numerics]

28.7 Mathematical functions for floating-point types [c.math]

28.7.1 Header <cmath> synopsis [cmath.syn]

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namespace std { using float_t = see below; using double_t = see below; } #define HUGE_VAL see below #define HUGE_VALF see below #define HUGE_VALL see below #define INFINITY see below #define NAN see below #define FP_INFINITE see below #define FP_NAN see below #define FP_NORMAL see below #define FP_SUBNORMAL see below #define FP_ZERO see below #define FP_FAST_FMA see below #define FP_FAST_FMAF see below #define FP_FAST_FMAL see below #define FP_ILOGB0 see below #define FP_ILOGBNAN see below #define MATH_ERRNO see below #define MATH_ERREXCEPT see below #define math_errhandling see below namespace std { constexpr floating-point-type acos(floating-point-type x); constexpr float acosf(float x); constexpr long double acosl(long double x); constexpr floating-point-type asin(floating-point-type x); constexpr float asinf(float x); constexpr long double asinl(long double x); constexpr floating-point-type atan(floating-point-type x); constexpr float atanf(float x); constexpr long double atanl(long double x); constexpr floating-point-type atan2(floating-point-type y, floating-point-type x); constexpr float atan2f(float y, float x); constexpr long double atan2l(long double y, long double x); constexpr floating-point-type cos(floating-point-type x); constexpr float cosf(float x); constexpr long double cosl(long double x); constexpr floating-point-type sin(floating-point-type x); constexpr float sinf(float x); constexpr long double sinl(long double x); constexpr floating-point-type tan(floating-point-type x); constexpr float tanf(float x); constexpr long double tanl(long double x); constexpr floating-point-type acosh(floating-point-type x); constexpr float acoshf(float x); constexpr long double acoshl(long double x); constexpr floating-point-type asinh(floating-point-type x); constexpr float asinhf(float x); constexpr long double asinhl(long double x); constexpr floating-point-type atanh(floating-point-type x); constexpr float atanhf(float x); constexpr long double atanhl(long double x); constexpr floating-point-type cosh(floating-point-type x); constexpr float coshf(float x); constexpr long double coshl(long double x); constexpr floating-point-type sinh(floating-point-type x); constexpr float sinhf(float x); constexpr long double sinhl(long double x); constexpr floating-point-type tanh(floating-point-type x); constexpr float tanhf(float x); constexpr long double tanhl(long double x); constexpr floating-point-type exp(floating-point-type x); constexpr float expf(float x); constexpr long double expl(long double x); constexpr floating-point-type exp2(floating-point-type x); constexpr float exp2f(float x); constexpr long double exp2l(long double x); constexpr floating-point-type expm1(floating-point-type x); constexpr float expm1f(float x); constexpr long double expm1l(long double x); constexpr floating-point-type frexp(floating-point-type value, int* exp); constexpr float frexpf(float value, int* exp); constexpr long double frexpl(long double value, int* exp); constexpr int ilogb(floating-point-type x); constexpr int ilogbf(float x); constexpr int ilogbl(long double x); constexpr floating-point-type ldexp(floating-point-type x, int exp); constexpr float ldexpf(float x, int exp); constexpr long double ldexpl(long double x, int exp); constexpr floating-point-type log(floating-point-type x); constexpr float logf(float x); constexpr long double logl(long double x); constexpr floating-point-type log10(floating-point-type x); constexpr float log10f(float x); constexpr long double log10l(long double x); constexpr floating-point-type log1p(floating-point-type x); constexpr float log1pf(float x); constexpr long double log1pl(long double x); constexpr floating-point-type log2(floating-point-type x); constexpr float log2f(float x); constexpr long double log2l(long double x); constexpr floating-point-type logb(floating-point-type x); constexpr float logbf(float x); constexpr long double logbl(long double x); constexpr floating-point-type modf(floating-point-type value, floating-point-type* iptr); constexpr float modff(float value, float* iptr); constexpr long double modfl(long double value, long double* iptr); constexpr floating-point-type scalbn(floating-point-type x, int n); constexpr float scalbnf(float x, int n); constexpr long double scalbnl(long double x, int n); constexpr floating-point-type scalbln(floating-point-type x, long int n); constexpr float scalblnf(float x, long int n); constexpr long double scalblnl(long double x, long int n); constexpr floating-point-type cbrt(floating-point-type x); constexpr float cbrtf(float x); constexpr long double cbrtl(long double x); // [c.math.abs], absolute values constexpr int abs(int j); // freestanding constexpr long int abs(long int j); // freestanding constexpr long long int abs(long long int j); // freestanding constexpr floating-point-type abs(floating-point-type j); // freestanding-deleted constexpr floating-point-type fabs(floating-point-type x); constexpr float fabsf(float x); constexpr long double fabsl(long double x); constexpr floating-point-type hypot(floating-point-type x, floating-point-type y); constexpr float hypotf(float x, float y); constexpr long double hypotl(long double x, long double y); // [c.math.hypot3], three-dimensional hypotenuse constexpr floating-point-type hypot(floating-point-type x, floating-point-type y, floating-point-type z); constexpr floating-point-type pow(floating-point-type x, floating-point-type y); constexpr float powf(float x, float y); constexpr long double powl(long double x, long double y); constexpr floating-point-type sqrt(floating-point-type x); constexpr float sqrtf(float x); constexpr long double sqrtl(long double x); constexpr floating-point-type erf(floating-point-type x); constexpr float erff(float x); constexpr long double erfl(long double x); constexpr floating-point-type erfc(floating-point-type x); constexpr float erfcf(float x); constexpr long double erfcl(long double x); constexpr floating-point-type lgamma(floating-point-type x); constexpr float lgammaf(float x); constexpr long double lgammal(long double x); constexpr floating-point-type tgamma(floating-point-type x); constexpr float tgammaf(float x); constexpr long double tgammal(long double x); constexpr floating-point-type ceil(floating-point-type x); constexpr float ceilf(float x); constexpr long double ceill(long double x); constexpr floating-point-type floor(floating-point-type x); constexpr float floorf(float x); constexpr long double floorl(long double x); floating-point-type nearbyint(floating-point-type x); float nearbyintf(float x); long double nearbyintl(long double x); floating-point-type rint(floating-point-type x); float rintf(float x); long double rintl(long double x); long int lrint(floating-point-type x); long int lrintf(float x); long int lrintl(long double x); long long int llrint(floating-point-type x); long long int llrintf(float x); long long int llrintl(long double x); constexpr floating-point-type round(floating-point-type x); constexpr float roundf(float x); constexpr long double roundl(long double x); constexpr long int lround(floating-point-type x); constexpr long int lroundf(float x); constexpr long int lroundl(long double x); constexpr long long int llround(floating-point-type x); constexpr long long int llroundf(float x); constexpr long long int llroundl(long double x); constexpr floating-point-type trunc(floating-point-type x); constexpr float truncf(float x); constexpr long double truncl(long double x); constexpr floating-point-type fmod(floating-point-type x, floating-point-type y); constexpr float fmodf(float x, float y); constexpr long double fmodl(long double x, long double y); constexpr floating-point-type remainder(floating-point-type x, floating-point-type y); constexpr float remainderf(float x, float y); constexpr long double remainderl(long double x, long double y); constexpr floating-point-type remquo(floating-point-type x, floating-point-type y, int* quo); constexpr float remquof(float x, float y, int* quo); constexpr long double remquol(long double x, long double y, int* quo); constexpr floating-point-type copysign(floating-point-type x, floating-point-type y); constexpr float copysignf(float x, float y); constexpr long double copysignl(long double x, long double y); double nan(const char* tagp); float nanf(const char* tagp); long double nanl(const char* tagp); constexpr floating-point-type nextafter(floating-point-type x, floating-point-type y); constexpr float nextafterf(float x, float y); constexpr long double nextafterl(long double x, long double y); constexpr floating-point-type nexttoward(floating-point-type x, long double y); constexpr float nexttowardf(float x, long double y); constexpr long double nexttowardl(long double x, long double y); constexpr floating-point-type fdim(floating-point-type x, floating-point-type y); constexpr float fdimf(float x, float y); constexpr long double fdiml(long double x, long double y); constexpr floating-point-type fmax(floating-point-type x, floating-point-type y); constexpr float fmaxf(float x, float y); constexpr long double fmaxl(long double x, long double y); constexpr floating-point-type fmin(floating-point-type x, floating-point-type y); constexpr float fminf(float x, float y); constexpr long double fminl(long double x, long double y); constexpr floating-point-type fma(floating-point-type x, floating-point-type y, floating-point-type z); constexpr float fmaf(float x, float y, float z); constexpr long double fmal(long double x, long double y, long double z); // [c.math.lerp], linear interpolation constexpr floating-point-type lerp(floating-point-type a, floating-point-type b, floating-point-type t) noexcept; // [c.math.fpclass], classification / comparison functions constexpr int fpclassify(floating-point-type x); constexpr bool isfinite(floating-point-type x); constexpr bool isinf(floating-point-type x); constexpr bool isnan(floating-point-type x); constexpr bool isnormal(floating-point-type x); constexpr bool signbit(floating-point-type x); constexpr bool isgreater(floating-point-type x, floating-point-type y); constexpr bool isgreaterequal(floating-point-type x, floating-point-type y); constexpr bool isless(floating-point-type x, floating-point-type y); constexpr bool islessequal(floating-point-type x, floating-point-type y); constexpr bool islessgreater(floating-point-type x, floating-point-type y); constexpr bool isunordered(floating-point-type x, floating-point-type y); // [sf.cmath], mathematical special functions // [sf.cmath.assoc.laguerre], associated Laguerre polynomials floating-point-type assoc_laguerre(unsigned n, unsigned m, floating-point-type x); float assoc_laguerref(unsigned n, unsigned m, float x); long double assoc_laguerrel(unsigned n, unsigned m, long double x); // [sf.cmath.assoc.legendre], associated Legendre functions floating-point-type assoc_legendre(unsigned l, unsigned m, floating-point-type x); float assoc_legendref(unsigned l, unsigned m, float x); long double assoc_legendrel(unsigned l, unsigned m, long double x); // [sf.cmath.beta], beta function floating-point-type beta(floating-point-type x, floating-point-type y); float betaf(float x, float y); long double betal(long double x, long double y); // [sf.cmath.comp.ellint.1], complete elliptic integral of the first kind floating-point-type comp_ellint_1(floating-point-type k); float comp_ellint_1f(float k); long double comp_ellint_1l(long double k); // [sf.cmath.comp.ellint.2], complete elliptic integral of the second kind floating-point-type comp_ellint_2(floating-point-type k); float comp_ellint_2f(float k); long double comp_ellint_2l(long double k); // [sf.cmath.comp.ellint.3], complete elliptic integral of the third kind floating-point-type comp_ellint_3(floating-point-type k, floating-point-type nu); float comp_ellint_3f(float k, float nu); long double comp_ellint_3l(long double k, long double nu); // [sf.cmath.cyl.bessel.i], regular modified cylindrical Bessel functions floating-point-type cyl_bessel_i(floating-point-type nu, floating-point-type x); float cyl_bessel_if(float nu, float x); long double cyl_bessel_il(long double nu, long double x); // [sf.cmath.cyl.bessel.j], cylindrical Bessel functions of the first kind floating-point-type cyl_bessel_j(floating-point-type nu, floating-point-type x); float cyl_bessel_jf(float nu, float x); long double cyl_bessel_jl(long double nu, long double x); // [sf.cmath.cyl.bessel.k], irregular modified cylindrical Bessel functions floating-point-type cyl_bessel_k(floating-point-type nu, floating-point-type x); float cyl_bessel_kf(float nu, float x); long double cyl_bessel_kl(long double nu, long double x); // [sf.cmath.cyl.neumann], cylindrical Neumann functions // cylindrical Bessel functions of the second kind floating-point-type cyl_neumann(floating-point-type nu, floating-point-type x); float cyl_neumannf(float nu, float x); long double cyl_neumannl(long double nu, long double x); // [sf.cmath.ellint.1], incomplete elliptic integral of the first kind floating-point-type ellint_1(floating-point-type k, floating-point-type phi); float ellint_1f(float k, float phi); long double ellint_1l(long double k, long double phi); // [sf.cmath.ellint.2], incomplete elliptic integral of the second kind floating-point-type ellint_2(floating-point-type k, floating-point-type phi); float ellint_2f(float k, float phi); long double ellint_2l(long double k, long double phi); // [sf.cmath.ellint.3], incomplete elliptic integral of the third kind floating-point-type ellint_3(floating-point-type k, floating-point-type nu, floating-point-type phi); float ellint_3f(float k, float nu, float phi); long double ellint_3l(long double k, long double nu, long double phi); // [sf.cmath.expint], exponential integral floating-point-type expint(floating-point-type x); float expintf(float x); long double expintl(long double x); // [sf.cmath.hermite], Hermite polynomials floating-point-type hermite(unsigned n, floating-point-type x); float hermitef(unsigned n, float x); long double hermitel(unsigned n, long double x); // [sf.cmath.laguerre], Laguerre polynomials floating-point-type laguerre(unsigned n, floating-point-type x); float laguerref(unsigned n, float x); long double laguerrel(unsigned n, long double x); // [sf.cmath.legendre], Legendre polynomials floating-point-type legendre(unsigned l, floating-point-type x); float legendref(unsigned l, float x); long double legendrel(unsigned l, long double x); // [sf.cmath.riemann.zeta], Riemann zeta function floating-point-type riemann_zeta(floating-point-type x); float riemann_zetaf(float x); long double riemann_zetal(long double x); // [sf.cmath.sph.bessel], spherical Bessel functions of the first kind floating-point-type sph_bessel(unsigned n, floating-point-type x); float sph_besself(unsigned n, float x); long double sph_bessell(unsigned n, long double x); // [sf.cmath.sph.legendre], spherical associated Legendre functions floating-point-type sph_legendre(unsigned l, unsigned m, floating-point-type theta); float sph_legendref(unsigned l, unsigned m, float theta); long double sph_legendrel(unsigned l, unsigned m, long double theta); // [sf.cmath.sph.neumann], spherical Neumann functions; // spherical Bessel functions of the second kind floating-point-type sph_neumann(unsigned n, floating-point-type x); float sph_neumannf(unsigned n, float x); long double sph_neumannl(unsigned n, long double x); }
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The contents and meaning of the header <cmath> are the same as the C standard library header <math.h>, with the addition of a three-dimensional hypotenuse function, a linear interpolation function, and the mathematical special functions described in [sf.cmath].
[Note 1: 
Several functions have additional overloads in this document, but they have the same behavior as in the C standard library.
— end note]
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For each function with at least one parameter of type floating-point-type, the implementation provides an overload for each cv-unqualified floating-point type ([basic.fundamental]) where all uses of floating-point-type in the function signature are replaced with that floating-point type.
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For each function with at least one parameter of type floating-point-type other than abs, the implementation also provides additional overloads sufficient to ensure that, if every argument corresponding to a floating-point-type parameter has arithmetic type, then every such argument is effectively cast to the floating-point type with the greatest floating-point conversion rank and greatest floating-point conversion subrank among the types of all such arguments, where arguments of integer type are considered to have the same floating-point conversion rank as double.
If no such floating-point type with the greatest rank and subrank exists, then overload resolution does not result in a usable candidate ([over.match.general]) from the overloads provided by the implementation.
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An invocation of nexttoward is ill-formed if the argument corresponding to the floating-point-type parameter has extended floating-point type.
See also: ISO/IEC 9899:2018, 7.12