std::fma

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Defined in header <cmath>
float       fma( float x, float y, float z );	(1)	(since C++11)
double      fma( double x, double y, double z );	(2)	(since C++11)
long double fma( long double x, long double y, long double z );	(3)	(since C++11)
Promoted    fma( Arithmetic x, Arithmetic y, Arithmetic z );	(4)	(since C++11)
#define FP_FAST_FMA  /* implementation-defined */	(5)	(since C++11)
#define FP_FAST_FMAF /* implementation-defined */	(6)	(since C++11)
#define FP_FAST_FMAL /* implementation-defined */	(7)	(since C++11)

The fma functions compute (x*y) + z, rounded as one ternary operation, according to the rounding mode characterized by the value of FLT_ROUNDS.

4) If any argument has integral type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double.

5-7) If the macro constants FP_FAST_FMAF, FP_FAST_FMA, or FP_FAST_FMAL are defined, the function std::fma evaluates faster than the expression x*y+z for float, double, and long double arguments, respectively. If defined, these macros evaluate to integer 1.

Parameters

x, y, z

-

floating point values

Return value

(x*y) + z, rounded as one ternary operation

See also

remainder (C++11)	signed remainder of the division operation (function)
remquo (C++11)	signed remainder as well as the three last bits of the division operation (function)