Mathematical Functions

Introduction
Installing/Configuring
Predefined Constants
Math Functions
- abs — Absolute value
- acos — Arc cosine
- acosh — Inverse hyperbolic cosine
- asin — Arc sine
- asinh — Inverse hyperbolic sine
- atan2 — Arc tangent of two variables
- atan — Arc tangent
- atanh — Inverse hyperbolic tangent
- base_convert — Convert a number between arbitrary bases
- bindec — Binary to decimal
- ceil — Round fractions up
- cos — Cosine
- cosh — Hyperbolic cosine
- decbin — Decimal to binary
- dechex — Decimal to hexadecimal
- decoct — Decimal to octal
- deg2rad — Converts the number in degrees to the radian equivalent
- exp — Calculates the exponent of e
- expm1 — Returns exp(number) - 1, computed in a way that is accurate even when the value of number is close to zero
- floor — Round fractions down
- fmod — Returns the floating point remainder (modulo) of the division of the arguments
- getrandmax — Show largest possible random value
- hexdec — Hexadecimal to decimal
- hypot — Calculate the length of the hypotenuse of a right-angle triangle
- is_finite — Finds whether a value is a legal finite number
- is_infinite — Finds whether a value is infinite
- is_nan — Finds whether a value is not a number
- lcg_value — Combined linear congruential generator
- log10 — Base-10 logarithm
- log1p — Returns log(1 + number), computed in a way that is accurate even when the value of number is close to zero
- log — Natural logarithm
- max — Find highest value
- min — Find lowest value
- mt_getrandmax — Show largest possible random value
- mt_rand — Generate a better random value
- mt_srand — Seed the better random number generator
- octdec — Octal to decimal
- pi — Get value of pi
- pow — Exponential expression
- rad2deg — Converts the radian number to the equivalent number in degrees
- rand — Generate a random integer
- round — Rounds a float
- sin — Sine
- sinh — Hyperbolic sine
- sqrt — Square root
- srand — Seed the random number generator
- tan — Tangent
- tanh — Hyperbolic tangent

add a note User Contributed Notes
Math

Sanjay Ichalkaranje
11-Oct-2008 10:34


This is the only function I searched that I did not find anywhere on the Internet. This function calculates standard normal cumulative distribution for a particular value. This is NORMSDIST(x) in MS-Excel or OpenOffice.org Calc program.



<?

function normalDist($zScore) {

    $p = floatval(0.2316419);

    $b1 = floatval(0.319381530);

    $b2 = floatval(-0.356563782);

    $b3 = floatval(1.781477937);

    $b4 = floatval(-1.821255978);

    $b5 = floatval(1.330274429);

    $t = 1/(1 + ($p * floatval($zScore)));

    $zx = (1/(sqrt(2 * pi())) * (exp(0 - pow($zScore, 2)/2)));



    $px = 1 - floatval($zx) * (($b1 * $t) + ($b2 * pow($t, 2)) + ($b3 * pow($t, 3)) + ($b4 * pow($t, 4)) + ($b5 * pow($t,5)));

    return $px;

}

?>

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Introduction

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Last updated: Fri, 28 Nov 2008