pow(3) [php man page]

POW(3)									 1								    POW(3)

pow - Exponential expression

SYNOPSIS

       number pow (number  $base, number  $exp)

DESCRIPTION

	Returns $base raised to the power of $exp.

       Note

	       In PHP 5.6 onwards, you may prefer to use the ** operator.

PARAMETERS

	      o $base
		- The base to use

	      o $exp
		- The exponent

RETURN VALUES

       $base  raised to the power of $exp. If both arguments are non-negative integers and the result can be represented as an integer, the result
       will be returned with integer type, otherwise it will be returned as a float.

EXAMPLES

       Example #1

	      Some examples of pow(3)

	      <?php

	      var_dump(pow(2, 8)); // int(256)
	      echo pow(-1, 20); // 1
	      echo pow(0, 0); // 1

	      echo pow(-1, 5.5); // PHP >4.0.6	NAN
	      echo pow(-1, 5.5); // PHP <=4.0.6 1.#IND
	      ?>

NOTES

       Note

	       This function will convert all input to a number, even non-scalar values, which could lead to weird results.

SEE ALSO

       exp(3), sqrt(3), bcpow(3), gmp_pow(3).

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NAME

     pow -- power function

SYNOPSIS

     #include <math.h>

     double
     pow(double x, double y);

     long double
     powl(long double x, long double y);

     float
     powf(float x, float y);

DESCRIPTION

     The pow() functions compute x raised to the power y.

SPECIAL VALUES

     pow(+-0, y) returns +-infinity and raises the "divide-by-zero" floating-point exception for y an odd integer < 0.

     pow(+-0, y) returns +infinity and raises the "divide-by-zero" floating-point exception for y < 0 and not an odd integer.

     pow(+-0, y) returns +-0 for y an odd integer > 0.

     pow(+-0, y) returns +0 for y > 0 and not an odd integer.

     pow(-1, +-infinity) returns 1.

     pow(1, y) returns 1 for any y, even a NaN.

     pow(x, +-0) returns 1 for any x, even a NaN.

     pow(x, y) returns a NaN and raises the "invalid" floating-point exception for finite x < 0 and finite non-integer y.

     pow(x, -infinity) returns +infinity for |x| < 1.

     pow(x, -infinity) returns +0 for |x| > 1.

     pow(x, +infinity) returns +0 for |x| < 1.

     pow(x, +infinity) returns +infinity for |x| > 1.

     pow(-infinity, y) returns -0 for y an odd integer < 0.

     pow(-infinity, y) returns +0 for y < 0 and not an odd integer.

     pow(-infinity, y) returns -infinity for y an odd integer > 0.

     pow(-infinity, y) returns +infinity for y > 0 and not an odd integer.

     pow(+infinity, y) returns +0 for y < 0.

     pow(+infinity, y) returns +infinity for y > 0.

     A domain error occurs if x is finite and negative and y is finite and not an integer.

     A domain error can occur if x is 0 and y less than or equal to 0.

     Range errors may occur.

VECTOR OPERATIONS

     If you need to apply the pow() functions to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
     give significantly better performance:

     #include <Accelerate/Accelerate.h>

     vFloat vpowf(vFloat x, vFloat y);
     vFloat vpowf(vFloat x, vSInt32 y);
     void vvpowf(float *z, const float *y, const float *x, const int *n);
     void vvpow(double *z, const double *y, const double *x, const int *n);
     void vvpowsf(float *z, const float *y, const float *x, const int *n);
     void vvpows(double *z, const double *y, const double *x, const int *n);

SEE ALSO

     exp(3) math(3)

STANDARDS

     The pow() function conforms to ISO/IEC 9899:2011.

4th Berkeley Distribution					 December 11, 2006					 4th Berkeley Distribution