ilMath Class Reference

Class ilMath. More...

Collaboration diagram for ilMath:

Public Member Functions
	exp2dec ($float_str)

Static Public Member Functions
static	_add ($left_operand, $right_operand, $scale=50)
static	_comp ($left_operand, $right_operand, $scale=50)
static	_div ($left_operand, $right_operand, $scale=50)
static	_mod ($left_operand, $modulus)
static	_mul ($left_operand, $right_operand, $scale=50)
static	_pow ($left_operand, $right_operand, $scale=50)
static	_sqrt ($operand, $scale=50)
static	_sub ($left_operand, $right_operand, $scale=50)

Detailed Description

Class ilMath.

Wrapper for mathematical operations

Author

Helmut Schottmüller helmu.nosp@m.t.sc.nosp@m.hottm.nosp@m.uell.nosp@m.er@ma.nosp@m.c.co.nosp@m.m

Id:

class.ilMath.php 20368 2009-06-29 08:38:26Z hschottm

Definition at line 32 of file class.ilMath.php.

Member Function Documentation

static ilMath::_add (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 37 of file class.ilMath.php.

References $res, and exp2dec().

Referenced by EvalMath\pfx().

        {
                if (function_exists("bcadd"))
                {
                        return bcadd(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        $res = $left_operand + $right_operand;
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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static ilMath::_comp (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 54 of file class.ilMath.php.

References exp2dec().

        {
                if (function_exists("bccomp"))
                {
                        return bccomp(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        if (is_numeric($scale)) 
                        {
                                $left_operand = round($left_operand, $scale);
                                $right_operand = round($right_operand, $scale);
                        }
                        if ($left_operand == $right_operand) return 0;
                        if ($left_operand > $right_operand) return 1;
                        return -1;
                }
        }

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static ilMath::_div (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 76 of file class.ilMath.php.

References $res, and exp2dec().

Referenced by EvalMath\pfx().

        {
                if (function_exists("bcdiv"))
                {
                        return bcdiv(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        if ($right_operand == 0) return NULL;
                        $res = $left_operand / $right_operand;
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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static ilMath::_mod (   $left_operand,   $modulus  )

static

Definition at line 94 of file class.ilMath.php.

References exp2dec().

        {
                if (function_exists("bcmod"))
                {
                        return bcmod(ilMath::exp2dec($left_operand), $modulus);
                }
                else
                {
                        return $left_operand % $right_operand;
                }
        }

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static ilMath::_mul (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 109 of file class.ilMath.php.

References $res, and exp2dec().

Referenced by EvalMath\pfx().

        {
                if (function_exists("bcmul"))
                {
                        return bcmul(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        $res = $left_operand * $right_operand;
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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static ilMath::_pow (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 126 of file class.ilMath.php.

References $res, and exp2dec().

Referenced by EvalMath\pfx().

        {
                if (function_exists("bcpow"))
                {
                        return bcpow(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        $res = pow($left_operand, $right_operand);
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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static ilMath::_sqrt (   $operand,   $scale = 50  )

static

Definition at line 143 of file class.ilMath.php.

References $res, and exp2dec().

        {
                if (function_exists("bcsqrt"))
                {
                        return bcsqrt(ilMath::exp2dec($operand), $scale);
                }
                else
                {
                        $res = sqrt($operand);
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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static ilMath::_sub (   $left_operand,   $right_operand,   $scale = 50  )

static

Definition at line 160 of file class.ilMath.php.

References $res, and exp2dec().

Referenced by EvalMath\pfx().

        {
                if (function_exists("bcsub"))
                {
                        return bcsub(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
                }
                else
                {
                        $res = $left_operand - $right_operand;
                        if (is_numeric($scale)) $res = round($res, $scale);
                        return $res;
                }
        }

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ilMath::exp2dec

(

$float_str

)

Definition at line 178 of file class.ilMath.php.

References $pos.

Referenced by _add(), _comp(), _div(), _mod(), _mul(), _pow(), _sqrt(), and _sub().

        {
                // make sure its a standard php float string (i.e. change 0.2e+2 to 20)
                // php will automatically format floats decimally if they are within a certain range
                $float_str = (string)((float)($float_str));

                // if there is an E in the float string
                if(($pos = strpos(strtolower($float_str), 'e')) !== false)
                {
                        // get either side of the E, e.g. 1.6E+6 => exp E+6, num 1.6
                        $exp = substr($float_str, $pos+1);
                        $num = substr($float_str, 0, $pos);

                        // strip off num sign, if there is one, and leave it off if its + (not required)
                        if((($num_sign = $num[0]) === '+') || ($num_sign === '-')) $num = substr($num, 1);
                        else $num_sign = '';
                        if($num_sign === '+') $num_sign = '';

                        // strip off exponential sign ('+' or '-' as in 'E+6') if there is one, otherwise throw error, e.g. E+6 => '+'
                        if((($exp_sign = $exp[0]) === '+') || ($exp_sign === '-')) $exp = substr($exp, 1);
                        else trigger_error("Could not convert exponential notation to decimal notation: invalid float string '$float_str'", E_USER_ERROR);

                        // get the number of decimal places to the right of the decimal point (or 0 if there is no dec point), e.g., 1.6 => 1
                        $right_dec_places = (($dec_pos = strpos($num, '.')) === false) ? 0 : strlen(substr($num, $dec_pos+1));
                        // get the number of decimal places to the left of the decimal point (or the length of the entire num if there is no dec point), e.g. 1.6 => 1
                        $left_dec_places = ($dec_pos === false) ? strlen($num) : strlen(substr($num, 0, $dec_pos));

                        // work out number of zeros from exp, exp sign and dec places, e.g. exp 6, exp sign +, dec places 1 => num zeros 5
                        if($exp_sign === '+') $num_zeros = $exp - $right_dec_places;
                        else $num_zeros = $exp - $left_dec_places;

                        // build a string with $num_zeros zeros, e.g. '0' 5 times => '00000'
                        $zeros = str_pad('', $num_zeros, '0');

                        // strip decimal from num, e.g. 1.6 => 16
                        if($dec_pos !== false) $num = str_replace('.', '', $num);

                        // if positive exponent, return like 1600000
                        if($exp_sign === '+') return $num_sign.$num.$zeros;
                        // if negative exponent, return like 0.0000016
                        else return $num_sign.'0.'.$zeros.$num;
                }
                // otherwise, assume already in decimal notation and return
                else return $float_str;
        }

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The documentation for this class was generated from the following file:

• Services/Math/classes/class.ilMath.php