Normal::xFromZScore() - Code Metrics - Inspection of "Added some helper functions to Normal distribution" - JordanRL/Fermat - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — dev ( 096a57...e2b70a )

by Jordan

created 2017-01-09 19:53 UTC

Normal::xFromZScore() A

↳ Parent: Normal

Complexity

Conditions	1
Paths	1

Size

Total Lines	6
Code Lines	3

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	6
rs	9.4285
c	0
b	0
f	0
cc	1
eloc	3
nc	1
nop	1

<?php

namespace Samsara\Fermat\Provider\Stats\Distribution;

use RandomLib\Factory;
use Samsara\Fermat\Numbers;
use Samsara\Fermat\Provider\Stats\Stats;
use Samsara\Fermat\Types\Base\NumberInterface;
use Samsara\Fermat\Values\ImmutableNumber;

class Normal
{

    /**
     * @var NumberInterface
     */
    private $mean;

    /**
     * @var NumberInterface
     */
    private $sd;

    public function __construct($mean, $sd)
    {
        $mean = Numbers::makeOrDont(Numbers::IMMUTABLE, $mean);
        $sd = Numbers::makeOrDont(Numbers::IMMUTABLE, $sd);

        $this->mean = $mean;
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;
}
        $this->sd = $sd;
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;
}
    }

    public static function makeFromMean($p, $x, $mean)

    {
        $one = Numbers::makeOne();
        $p = Numbers::makeOrDont(Numbers::IMMUTABLE, $p);
        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
        $mean = Numbers::makeOrDont(Numbers::IMMUTABLE, $mean);

        $z = Stats::inverseNormalCDF($one->subtract($p));

        $sd = $x->subtract($mean)->divide($z);

        return new Normal($mean, $sd);
    }

    public static function makeFromSd($p, $x, $sd)

    {
        $one = Numbers::makeOne();
        $p = Numbers::makeOrDont(Numbers::IMMUTABLE, $p);
        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
        $sd = Numbers::makeOrDont(Numbers::IMMUTABLE, $sd);

        $z = Stats::inverseNormalCDF($one->subtract($p));

        $mean = $x->subtract($z->multiply($sd));

        return new Normal($mean, $sd);
    }
    
    public function cdf($x)
    {
        $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);

        if (function_exists('stats_cdf_normal') &&
            $x->isLessThanOrEqualTo(PHP_INT_MAX) &&
            $x->isGreaterThanOrEqualTo(PHP_INT_MIN) &&
            $this->mean->isLessThanOrEqualTo(PHP_INT_MAX) &&
            $this->mean->isGreaterThanOrEqualTo(PHP_INT_MIN) &&
            $this->sd->isLessThanOrEqualTo(PHP_INT_MAX) &&
            $this->sd->isGreaterThanOrEqualTo(PHP_INT_MIN)) {
            return Numbers::make(Numbers::IMMUTABLE, stats_cdf_normal($x->getValue(), $this->mean, $this->sd));
        }

        $oneHalf = Numbers::make(Numbers::IMMUTABLE, '0.5');
        $one = Numbers::makeOne();
        $sqrtTwo = Numbers::make(Numbers::IMMUTABLE, 2)->sqrt();

        return $oneHalf->multiply($one->add(Stats::gaussErrorFunction(
            $x->subtract($this->mean)->divide($this->sd->multiply($sqrtTwo))
        )));
    }
    
    public function pdf($x1, $x2)
    {
        return $this->cdf($x1)->subtract($this->cdf($x2))->abs();
    }

    public function percentBelowX($x)
    {
        return $this->cdf($x);
    }

    public function percentAboveX($x)
    {
        $one = Numbers::makeOne();

        return $one->subtract($this->cdf($x));
    }

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

        return $x->subtract($this->mean)->divide($this->sd);
    }

    public function xFromZScore($z)
    {
        $z = Numbers::makeOrDont(Numbers::IMMUTABLE, $z);

        return $z->multiply($this->sd)->add($this->mean);
    }

    /**
     * @return ImmutableNumber
     */
    public function random()
    {
        if (function_exists('stats_rand_gen_normal')) {
            return Numbers::make(Numbers::IMMUTABLE, stats_rand_gen_normal($this->mean, $this->sd), 20);
        } else {
            $randFactory = new Factory();
            $generator = $randFactory->getMediumStrengthGenerator();

            $rand1 = Numbers::make(Numbers::IMMUTABLE, $generator->generateInt(), 20);
            $rand1 = $rand1->divide(PHP_INT_MAX);
            $rand2 = Numbers::make(Numbers::IMMUTABLE, $generator->generateInt(), 20);
            $rand2 = $rand2->divide(PHP_INT_MAX);

            $randomNumber = $rand1->ln()->multiply(-2)->sqrt()->multiply($rand2->multiply(Numbers::TAU)->cos(1, 2, 20));
interface User
{
    /** @return string */
    public function getPassword();
}

class MyUser implements User
{
    public function getPassword()
    {
        // return something
    }

    public function getDisplayName()
    {
        // return some name.
    }
}

class AuthSystem
{
    public function authenticate(User $user)
    {
        $this->logger->info(sprintf('Authenticating %s.', $user->getDisplayName()));
        // do something.
    }
}
            $randomNumber = $randomNumber->multiply($this->sd)->add($this->mean);

            return $randomNumber;
        }
    }
    
    public function rangeRandom($min = 0, $max = PHP_INT_MAX, $maxIterations = 20)
    {
        $i = 0;

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

        if ($randomNumber->isGreaterThan($max) || $randomNumber->isLessThan($min)) {
            throw new \Exception();
        } else {
            return $randomNumber;
        }
    }

}

1		<?php
2
3		namespace Samsara\Fermat\Provider\Stats\Distribution;
4
5		use RandomLib\Factory;
6		use Samsara\Fermat\Numbers;
7		use Samsara\Fermat\Provider\Stats\Stats;
8		use Samsara\Fermat\Types\Base\NumberInterface;
9		use Samsara\Fermat\Values\ImmutableNumber;
10
11		class Normal
12		{
13
14		/**
15		* @var NumberInterface
16		*/
17		private $mean;
18
19		/**
20		* @var NumberInterface
21		*/
22		private $sd;
23
24		public function __construct($mean, $sd)
25		{
26		$mean = Numbers::makeOrDont(Numbers::IMMUTABLE, $mean);
27		$sd = Numbers::makeOrDont(Numbers::IMMUTABLE, $sd);
28
29		$this->mean = $mean;
		0 ignored issues – show Documentation Bug introduced 2017-01-09 07:15 UTC by Report Bug Copy Issue Report It seems like `$mean` can also be of type `array`. However, the property `$mean` is declared as type `object<Samsara\Fermat\Types\Base\NumberInterface>`. Maybe add an additional type check? Our type inference engine has found a suspicous assignment of a value to a property. This check raises an issue when a value that can be of a mixed type is assigned to a property that is type hinted more strictly. For example, imagine you have a variable `$accountId` that can either hold an Id object or false (if there is no account id yet). Your code now assigns that value to the `id` property of an instance of the `Account` class. This class holds a proper account, so the id value must no longer be false. Either this assignment is in error or a type check should be added for that assignment. 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; } Loading history...
30		$this->sd = $sd;
		0 ignored issues – show Documentation Bug introduced 2017-01-09 07:15 UTC by Report Bug Copy Issue Report It seems like `$sd` can also be of type `array`. However, the property `$sd` is declared as type `object<Samsara\Fermat\Types\Base\NumberInterface>`. Maybe add an additional type check? Our type inference engine has found a suspicous assignment of a value to a property. This check raises an issue when a value that can be of a mixed type is assigned to a property that is type hinted more strictly. For example, imagine you have a variable `$accountId` that can either hold an Id object or false (if there is no account id yet). Your code now assigns that value to the `id` property of an instance of the `Account` class. This class holds a proper account, so the id value must no longer be false. Either this assignment is in error or a type check should be added for that assignment. 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 = $account_id; } Loading history...
31		}
32
33	View Code Duplication	public static function makeFromMean($p, $x, $mean)
		0 ignored issues – show Duplication introduced 2016-11-07 23:46 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
34		{
35		$one = Numbers::makeOne();
36		$p = Numbers::makeOrDont(Numbers::IMMUTABLE, $p);
37		$x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
38		$mean = Numbers::makeOrDont(Numbers::IMMUTABLE, $mean);
39
40		$z = Stats::inverseNormalCDF($one->subtract($p));
41
42		$sd = $x->subtract($mean)->divide($z);
43
44		return new Normal($mean, $sd);
45		}
46
47	View Code Duplication	public static function makeFromSd($p, $x, $sd)
		0 ignored issues – show Duplication introduced 2016-11-07 23:46 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
48		{
49		$one = Numbers::makeOne();
50		$p = Numbers::makeOrDont(Numbers::IMMUTABLE, $p);
51		$x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
52		$sd = Numbers::makeOrDont(Numbers::IMMUTABLE, $sd);
53
54		$z = Stats::inverseNormalCDF($one->subtract($p));
55
56		$mean = $x->subtract($z->multiply($sd));
57
58		return new Normal($mean, $sd);
59		}
60
61		public function cdf($x)
62		{
63		$x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
64
65		if (function_exists('stats_cdf_normal') &&
66		$x->isLessThanOrEqualTo(PHP_INT_MAX) &&
67		$x->isGreaterThanOrEqualTo(PHP_INT_MIN) &&
68		$this->mean->isLessThanOrEqualTo(PHP_INT_MAX) &&
69		$this->mean->isGreaterThanOrEqualTo(PHP_INT_MIN) &&
70		$this->sd->isLessThanOrEqualTo(PHP_INT_MAX) &&
71		$this->sd->isGreaterThanOrEqualTo(PHP_INT_MIN)) {
72		return Numbers::make(Numbers::IMMUTABLE, stats_cdf_normal($x->getValue(), $this->mean, $this->sd));
73		}
74
75		$oneHalf = Numbers::make(Numbers::IMMUTABLE, '0.5');
76		$one = Numbers::makeOne();
77		$sqrtTwo = Numbers::make(Numbers::IMMUTABLE, 2)->sqrt();
78
79		return $oneHalf->multiply($one->add(Stats::gaussErrorFunction(
80		$x->subtract($this->mean)->divide($this->sd->multiply($sqrtTwo))
81		)));
82		}
83
84		public function pdf($x1, $x2)
85		{
86		return $this->cdf($x1)->subtract($this->cdf($x2))->abs();
87		}
88
89		public function percentBelowX($x)
90		{
91		return $this->cdf($x);
92		}
93
94		public function percentAboveX($x)
95		{
96		$one = Numbers::makeOne();
97
98		return $one->subtract($this->cdf($x));
99		}
100
101		public function zScoreOfX($x)
102		{
103		$x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x);
104
105		return $x->subtract($this->mean)->divide($this->sd);
106		}
107
108		public function xFromZScore($z)
109		{
110		$z = Numbers::makeOrDont(Numbers::IMMUTABLE, $z);
111
112		return $z->multiply($this->sd)->add($this->mean);
113		}
114
115		/**
116		* @return ImmutableNumber
117		*/
118		public function random()
119		{
120		if (function_exists('stats_rand_gen_normal')) {
121		return Numbers::make(Numbers::IMMUTABLE, stats_rand_gen_normal($this->mean, $this->sd), 20);
122		} else {
123		$randFactory = new Factory();
124		$generator = $randFactory->getMediumStrengthGenerator();
125
126		$rand1 = Numbers::make(Numbers::IMMUTABLE, $generator->generateInt(), 20);
127		$rand1 = $rand1->divide(PHP_INT_MAX);
128		$rand2 = Numbers::make(Numbers::IMMUTABLE, $generator->generateInt(), 20);
129		$rand2 = $rand2->divide(PHP_INT_MAX);
130
131		$randomNumber = $rand1->ln()->multiply(-2)->sqrt()->multiply($rand2->multiply(Numbers::TAU)->cos(1, 2, 20));
		0 ignored issues – show Bug introduced 2017-01-09 19:42 UTC by Report Bug Copy Issue Report It seems like you code against a concrete implementation and not the interface `Samsara\Fermat\Types\Base\NumberInterface` as the method `cos()` does only exist in the following implementations of said interface: `Samsara\Fermat\Values\Currency`, `Samsara\Fermat\Values\ImmutableNumber`, `Samsara\Fermat\Values\MutableNumber`. Let’s take a look at an example: interface User { /** @return string / public function getPassword(); } class MyUser implements User { public function getPassword() { // return something } public function getDisplayName() { // return some name. } } class AuthSystem { public function authenticate(User $user) { $this->logger->info(sprintf('Authenticating %s.', $user->getDisplayName())); // do something. } } In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break. Available Fixes Change the type-hint for the parameter: class AuthSystem { public function authenticate(MyUser $user) { / ... / } } Add an additional type-check: class AuthSystem { public function authenticate(User $user) { if ($user instanceof MyUser) { $this->logger->info(/* ... /); } // or alternatively if ( ! $user instanceof MyUser) { throw new \LogicException( '$user must be an instance of MyUser, ' .'other instances are not supported.' ); } } } Note:* PHP Analyzer uses reverse abstract interpretation to narrow down the types inside the if block in such a case. Add the method to the interface: interface User { /** @return string / public function getPassword(); /* @return string */ public function getDisplayName(); } Loading history...
132		$randomNumber = $randomNumber->multiply($this->sd)->add($this->mean);
133
134		return $randomNumber;
135		}
136		}
137
138		public function rangeRandom($min = 0, $max = PHP_INT_MAX, $maxIterations = 20)
139		{
140		$i = 0;
141
142		do {
143		$randomNumber = $this->random();
144		$i++;
145		} while ($randomNumber->isLessThanOrEqualTo($max) && $randomNumber->isGreaterThanOrEqualTo($min) && $i < $maxIterations);
146
147		if ($randomNumber->isGreaterThan($max) \|\| $randomNumber->isLessThan($min)) {
148		throw new \Exception();
149		} else {
150		return $randomNumber;
151		}
152		}
153
154		}

JordanRL / Fermat

Push — dev ( 096a57...e2b70a )

Normal::xFromZScore() A

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