Poisson::random() - Code Metrics - Inspection of "Merge Number Collection Code Into dev" - JordanRL/Fermat - Measure and Improve Code Quality continuously with Scrutinizer

Completed
Pull Request — dev (#23)

by Jordan
created 2018-01-30 20:11 UTC
Poisson::random() A

↳ Parent: Poisson
Complexity

Conditions	2
Paths	2
Size

Total Lines	8
Code Lines	5
Duplication

Lines	0
Ratio	0 %
Code Coverage

Tests	0
CRAP Score	6
Importance

Changes
Metric	Value
dl	0
loc	8
ccs	0
cts	8
cp	0
rs	9.4285
c	0
b	0
f	0
cc	2
eloc	5
nc	2
nop	0
crap	6
<?php

namespace Samsara\Fermat\Provider\Distribution;

use RandomLib\Factory;
use Samsara\Exceptions\SystemError\LogicalError\IncompatibleObjectState;
use Samsara\Exceptions\UsageError\IntegrityConstraint;
use Samsara\Exceptions\UsageError\OptionalExit;
use Samsara\Fermat\Numbers;
use Samsara\Fermat\Provider\Distribution\Base\Distribution;
use Samsara\Fermat\Types\Base\DecimalInterface;
use Samsara\Fermat\Types\Base\NumberInterface;
use Samsara\Fermat\Values\ImmutableNumber;

class Poisson extends Distribution
{

    /**
     * @var ImmutableNumber
     */
    private $lambda;

    /**
     * Poisson constructor.
     *
     * @param int|float|DecimalInterface $lambda
     *
     * @throws IntegrityConstraint
     */
    public function __construct($lambda)

    {
        $lambda = Numbers::makeOrDont(Numbers::IMMUTABLE, $lambda);

        if (!$lambda->isPositive()) {
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            throw new IntegrityConstraint(
                'Lambda must be positive',
                'Provide a positive lambda',
                'Poisson distributions work on time to occurrence; the mean time to occurrence (lambda) must be positive'
            );
        }

        $this->lambda = $lambda;

    }

    /**
     * @param int|float|DecimalInterface $k
     *
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     * @throws IncompatibleObjectState
     */
    public function probabilityOfKEvents($k): ImmutableNumber
    {

        return $this->pmf($k);
        
    }

    /**
     * @param int|float|DecimalInterface $x
     *
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     * @throws IncompatibleObjectState
     */
    public function cdf($x): ImmutableNumber
    {

        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);

        if (!$x->isNatural()) {
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            throw new IntegrityConstraint(
                'Only integers are valid x values for Poisson distributions',
                'Provide an integer value to calculate the CDF',
                'Poisson distributions describe discrete occurrences; only integers are valid x values'
            );
        }

        $cumulative = Numbers::makeZero();

        for ($i = 0;$x->isGreaterThanOrEqualTo($i);$i++) {
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            $cumulative = $cumulative->add($this->pmf($i));
        }

        return $cumulative;

    }

    /**
     * @param int|float|DecimalInterface $x
     *
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     * @throws IncompatibleObjectState
     */
    public function pmf($x): ImmutableNumber

    {
        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);

        if (!$x->isNatural()) {
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            throw new IntegrityConstraint(
                'Only integers are valid x values for Poisson distributions',
                'Provide an integer value to calculate the PMF',
                'Poisson distributions describe discrete occurrences; only integers are valid x values'
            );
        }

        $e = Numbers::makeE();

        /** @var ImmutableNumber $pmf */
        $pmf = $this->lambda->pow($x)->multiply($e->pow($this->lambda->multiply(-1)))->divide($x->factorial());
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}

        return $pmf;
    }

    /**
     * @param int|float|DecimalInterface $x1
     * @param int|float|DecimalInterface $x2
     *
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     */
    public function rangePmf($x1, $x2): ImmutableNumber
    {
        $x1 = Numbers::makeOrDont(Numbers::IMMUTABLE, $x1);
        $x2 = Numbers::makeOrDont(Numbers::IMMUTABLE, $x2);

        if ($x1->equals($x2)) {
            return Numbers::makeZero();
        } elseif ($x1->isGreaterThan($x2)) {
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
            $larger = $x1;
            $smaller = $x2;
        } else {
            $larger = $x2;
            $smaller = $x1;
        }

        if (!$larger->isNatural() || !$smaller->isNatural()) {
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            throw new IntegrityConstraint(
                'Only integers are valid x values for Poisson distributions',
                'Provide integer values to calculate the range PMF',
                'Poisson distributions describe discrete occurrences; only integers are valid x values'
            );
        }

        $cumulative = Numbers::makeZero();

        for (;$larger->isGreaterThanOrEqualTo($smaller);$smaller->add(1)) {
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
            $cumulative = $cumulative->add($this->pmf($smaller));
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
        }

        return $cumulative;
    }

    /**
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     * @throws IncompatibleObjectState
     */
    public function random(): ImmutableNumber
    {
        if ($this->lambda->isLessThanOrEqualTo(30)) {
            return $this->knuthRandom();
        } else {
            return $this->methodPARandom();
        }
    }

    /**
     * WARNING: This function is of very limited use with Poisson distributions, and may represent a SIGNIFICANT
     * performance hit for certain values of $min, $max, $lambda, and $maxIterations
     *
     * @param int|float|NumberInterface $min
     * @param int|float|NumberInterface $max
     * @param int $maxIterations
     *
     * @throws OptionalExit
     * @return ImmutableNumber
     */
    public function rangeRandom($min = 0, $max = PHP_INT_MAX, int $maxIterations = 20): ImmutableNumber

    {
        $i = 0;

        do {
            $randomNumber = $this->random();
            $i++;
        } while (($randomNumber->isGreaterThan($max) || $randomNumber->isLessThan($min)) && $i < $maxIterations);

        if ($randomNumber->isGreaterThan($max) || $randomNumber->isLessThan($min)) {
            throw new OptionalExit(
                'All random numbers generated were outside of the requested range',
                'A suitable random number, restricted by the $max ('.$max.') and $min ('.$min.'), could not be found within '.$maxIterations.' iterations'
            );
        } else {
            return $randomNumber;
        }
    }

    /**
     * Method PA from The Computer Generation of Poisson Random Variables by A. C. Atkinson, 1979
     * Journal of the Royal Statistical Society Series C, Vol. 28, No. 1, Pages 29-35
     *
     * As described by John D. Cook: http://www.johndcook.com/blog/2010/06/14/generating-poisson-random-values/
     *
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     * @throws IncompatibleObjectState
     */
    protected function methodPARandom(): ImmutableNumber
    {
        $randFactory = new Factory();
        $generator = $randFactory->getMediumStrengthGenerator();
        /** @var ImmutableNumber $c */
        $c = $this->lambda->pow(-1)->multiply(3.36)->multiply(-1)->add(0.767);
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
        /** @var ImmutableNumber $beta */
        $beta = Numbers::makePi()->divide($this->lambda->multiply(3)->sqrt());
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
        /** @var ImmutableNumber $alpha */
        $alpha = $this->lambda->multiply($beta);
        /** @var ImmutableNumber $k */
        $k = $c->ln(20)->subtract($this->lambda)->subtract($beta->ln(20));
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
        /** @var ImmutableNumber $one */
        $one = Numbers::makeOne();
        /** @var ImmutableNumber $oneHalf */
        $oneHalf = Numbers::make(Numbers::IMMUTABLE, '0.5');
        /** @var ImmutableNumber $e */
        $e = Numbers::makeE();

        while (true) {
            /** @var ImmutableNumber $u */
            $u = $generator->generateInt() / PHP_INT_MAX;
            /** @var ImmutableNumber $x */
            $x = $alpha->subtract($one->subtract($u)->divide($u)->ln(20)->divide($beta));
            /** @var ImmutableNumber $n */
            $n = $x->add($oneHalf)->floor();

            if ($n->isNegative()) {
                continue;
            }

            /** @var ImmutableNumber $v */
            $v = $generator->generateInt() / PHP_INT_MAX;
            /** @var ImmutableNumber $y */
            $y = $alpha->subtract($beta->multiply($x));
            /** @var ImmutableNumber $lhs */
            $lhs = $y->add($v->divide($e->pow($y)->add($one)->pow(2)));
class A
{
    public function foo() { }
}

class B extends A
{
    public function bar() { }
}

/**
 * @param A|B $x
 */
function someFunction($x)
{
    $x->foo(); // This call is fine as the method exists in A and B.
    $x->bar(); // This method only exists in B and might cause an error.
}
            /** @var ImmutableNumber $rhs */
            $rhs = $k->add($n->multiply($this->lambda->ln(20)))->subtract($n->factorial()->ln(20));

            if ($lhs->isLessThanOrEqualTo($rhs)) {
                return $n;
            }

            /*
             * At least attempt to free up some memory, since this particular method is extra hard on object instantiation
             */
            unset($u);
            unset($x);
            unset($n);
            unset($v);
            unset($y);
            unset($lhs);
            unset($rhs);
        }
    }

    /**
     * @return ImmutableNumber
     * @throws IntegrityConstraint
     */
    protected function knuthRandom(): ImmutableNumber
    {
        $randFactory = new Factory();
        /** @var ImmutableNumber $L */
        $L = Numbers::makeE()->pow($this->lambda->multiply(-1));
        /** @var ImmutableNumber $k */
        $k = Numbers::makeZero();
        /** @var ImmutableNumber $p */
        $p = Numbers::makeOne();

        do {
            $k = $k->add(1);
            /** @var ImmutableNumber $u */
            $u = $randFactory->getMediumStrengthGenerator()->generateInt() / PHP_INT_MAX;
            $p = $p->multiply($u);
        } while ($p->isGreaterThan($L));

        return $k->subtract(1);
    }

}
Pull Request — dev (#23)

Poisson::random() A

Complexity

Size

Duplication

Code Coverage

Importance

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

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JordanRL / Fermat

Pull Request — dev (#23)

Poisson::random() A

Complexity

Size

Duplication

Code Coverage

Importance

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Available Fixes

Duplication Side-by-Side

Filter issues like
