Exponential::rangeRandom() - Code Metrics - Inspection of "Merge pull request #140 from JordanRL/f-documentat..." - JordanRL/Fermat - Measure and Improve Code Quality continuously with Scrutinizer

Completed
Push — master ( 5d186e...d62f94 )

by Jordan
created 2022-10-19 17:05 UTC
Exponential::rangeRandom() A

↳ Parent: Exponential
Complexity

Conditions	6
Paths	2
Size

Total Lines	18
Code Lines	10
Duplication

Lines	0
Ratio	0 %
Code Coverage

Tests	0
CRAP Score	42
Importance

Changes	1
Bugs	0	Features	0
Metric	Value
cc	6
dl	0
loc	18
ccs	0
cts	0
cp	0
crap	42
rs	9.2222
c	1
b	0
f	0
eloc	10
nc	2
nop	3
<?php

namespace Samsara\Fermat\Stats\Values\Distribution;

use Samsara\Exceptions\UsageError\IntegrityConstraint;
use Samsara\Exceptions\UsageError\OptionalExit;
use Samsara\Fermat\Core\Numbers;
use Samsara\Fermat\Stats\Types\Distribution;
use Samsara\Fermat\Core\Provider\RandomProvider;
use Samsara\Fermat\Core\Types\Base\Interfaces\Numbers\DecimalInterface;
use Samsara\Fermat\Core\Values\ImmutableDecimal;

class Exponential extends Distribution
{

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

    /**
     * Exponential constructor.
     *
     * @param int|float|DecimalInterface $lambda This is the *rate parameter* not the *scale parameter*
     *
     * @throws IntegrityConstraint
     */
    public function __construct($lambda)
    {
        $lambda = Numbers::makeOrDont(Numbers::IMMUTABLE, $lambda);

        if (!$lambda->isPositive()) {
        if (!$lambda->/** @scrutinizer ignore-call */ isPositive()) {
            throw new IntegrityConstraint(
                'Lambda must be positive',
                'Provide a positive lambda',
                'Exponential distributions work on time to occurrence; the mean time to occurrence (lambda) must be positive'
            );
        }

        $this->lambda = $lambda;
class Id
{
    public $id;

    public function __construct($id)
    {
        $this->id = $id;
    }

}

class Account
{
    /** @var  Id $id */
    public $id;
}

$account_id = false;

if (starsAreRight()) {
    $account_id = new Id(42);
}

$account = new Account();
if ($account instanceof Id)
{
    $account->id = $account_id;
}
    }

    /**
     * @param int|float|DecimalInterface $x
     *
     * @return ImmutableDecimal
     * @throws IntegrityConstraint
     */
    public function cdf($x, int $scale = 10): ImmutableDecimal
    {

        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
        /** @var ImmutableDecimal $one */
        $one = Numbers::makeOne();

        if (!$x->isPositive()) {
            throw new IntegrityConstraint(
                'X must be positive',
                'Provide a positive x',
                'Exponential distributions work on time to occurrence; the time to occurrence (x) must be positive'
            );
        }

        $internalScale = $scale + 2;

        /** @var ImmutableDecimal $e */
        $e = Numbers::makeE($internalScale);

        /** @var ImmutableDecimal $cdf */
        $cdf =
            $one->subtract(
                $e->pow(
                    $x->multiply($this->lambda)
                        ->multiply(-1)
                )
            )->truncateToScale($scale);

        return $cdf;

    }

    /**
     * @param $x
     *
     * @return ImmutableDecimal
     * @throws IntegrityConstraint
     */
    public function pdf($x, int $scale = 10): ImmutableDecimal
    {

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

        if (!$x->isPositive()) {
            throw new IntegrityConstraint(
                'X must be positive',
                'Provide a positive x',
                'Exponential distributions work on time to occurrence; the time to occurrence (x) must be positive'
            );
        }

        $internalScale = $scale + 2;

        /** @var ImmutableDecimal $e */
        $e = Numbers::makeE($internalScale);

        /** @var ImmutableDecimal $pdf */
        $pdf =
            $this->lambda
                ->multiply(
                    $e->pow(
                        $this->lambda
                            ->multiply(-1)
                            ->multiply($x)
                    )
                )->truncateToScale($scale);

        return $pdf;

    }

    /**
     * @param $x1
     * @param $x2
     *
     * @return ImmutableDecimal
     * @throws IntegrityConstraint
     */
    public function rangePdf($x1, $x2, int $scale = 10): ImmutableDecimal
    {
        $x1 = Numbers::makeOrDont(Numbers::IMMUTABLE, $x1);
        $x2 = Numbers::makeOrDont(Numbers::IMMUTABLE, $x2);

        if (!$x1->isPositive() || !$x2->isPositive()) {
            throw new IntegrityConstraint(
                'X must be positive',
                'Provide a positive x',
                'Exponential distributions work on time to occurrence; the time to occurrence (x) must be positive'
            );
        }

        $internalScale = $scale + 2;

        /** @var ImmutableDecimal $rangePdf */
        $rangePdf =
            $this->pdf(
                $x2,
                $internalScale
            )->subtract(
                $this->pdf(
                    $x1,
                    $internalScale)
            )->abs()
            ->truncateToScale($scale);
            ->/** @scrutinizer ignore-call */ truncateToScale($scale);

        return $rangePdf;
    }

    /**
     * @return ImmutableDecimal
     *
     * @codeCoverageIgnore
     */
    public function random(): ImmutableDecimal
    {

        $u = RandomProvider::randomDecimal(10);
        $one = Numbers::makeOne();

        /** @var ImmutableDecimal $random */
        $random =
            $one->subtract($u)
                ->ln()
                ->divide(
                    $this->lambda
                        ->multiply(-1)
                );

        return $random;

    }

    /**
     * @param int|float|DecimalInterface $min
     * @param int|float|DecimalInterface $max
     * @param int $maxIterations
     *
     * @return ImmutableDecimal
     * @throws OptionalExit
     *
     * @codeCoverageIgnore
     */
    public function rangeRandom($min = 0, $max = PHP_INT_MAX, int $maxIterations = 20): ImmutableDecimal
    {

        $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'
                'A suitable random number, restricted by the $max ('./** @scrutinizer ignore-type */ $max.') and $min ('.$min.'), could not be found within '.$maxIterations.' iterations'
            );
        }

        return $randomNumber;
    }

}
JordanRL / Fermat

Push — master ( 5d186e...d62f94 )

Exponential::rangeRandom() A

Complexity

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