std::expm1

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Numerics library

Common mathematical functions

Floating-point environment

Complex numbers

Numeric arrays

Pseudo-random number generation

Compile-time rational arithmetic (C++11)

Generic numeric operations

iota (C++11)

accumulate

inner_product

adjacent_difference

partial_sum

 

Common mathematical functions

Functions
Basic operations
abs(int) labs llabs imaxabs (C++11) abs(float) fabs div ldiv lldiv imaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nan nanf nanl (C++11) (C++11) (C++11)
Exponential functions
exp exp2 (C++11) expm1 (C++11)	log log10 log1p (C++11) log2 (C++11)
Power functions
sqrt cbrt (C++11)	hypot (C++11) pow
Trigonometric and hyperbolic functions
sin cos tan asin acos atan atan2	sinh cosh tanh asinh (C++11) acosh (C++11) atanh (C++11)
Error and gamma functions
erf (C++11) erfc (C++11)	lgamma (C++11) tgamma (C++11)
Nearest integer floating point operations
ceil floor round lround llround (C++11) (C++11) (C++11)	trunc (C++11) nearbyint (C++11) rint lrint llrint (C++11) (C++11) (C++11)
Floating point manipulation functions
ldexp scalbn scalbln (C++11) (C++11) ilogb (C++11) logb (C++11)	frexp modf nextafter nexttoward (C++11) (C++11) copysign (C++11)
Classification
fpclassify (C++11) isfinite (C++11) isinf (C++11)	isnan (C++11) isnormal (C++11) signbit (C++11)
Macro constants
HUGE_VALF HUGE_VAL HUGE_VALL (C++11) (C++11) INFINITY (C++11) NAN (C++11) math_errhandling MATH_ERRNO MATH_ERREXCEPT (C++11)	FP_NORMAL FP_SUBNORMAL FP_ZERO FP_INFINITE FP_NAN (C++11) (C++11) (C++11) (C++11) (C++11) FLT_EVAL_METHOD (C++11)

 

Defined in header <cmath>
float       expm1( float arg );		(since C++11)
double      expm1( double arg );		(since C++11)
long double expm1( long double arg );		(since C++11)
double      expm1( Integral arg );		(since C++11)

Computes the e (Euler's number, 2.7182818) raised to the given power arg, minus 1. This function is more accurate than the expression std::exp(arg)-1 if arg is close to zero.

Parameters

arg

-

floating point value

Return value

earg
-1

If the result is too large for the underlying type, range error occurs and HUGE_VAL is returned.

See also

exp	returns e raised to the given power (ex) (function)
exp2 (C++11)	returns 2 raised to the given power (2x) (function)