JordanRL /
Fermat
| @@ 49-72 (lines=24) @@ | ||
| 46 | * @return ImmutableNumber |
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| 47 | * @throws IntegrityConstraint |
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| 48 | */ |
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| 49 | public function cdf($x): ImmutableNumber |
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| 50 | { |
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| 51 | ||
| 52 | $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x); |
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| 53 | /** @var ImmutableNumber $one */ |
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| 54 | $one = Numbers::makeOne(); |
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| 55 | ||
| 56 | if (!$x->isPositive()) { |
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| 57 | throw new IntegrityConstraint( |
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| 58 | 'X must be positive', |
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| 59 | 'Provide a positive x', |
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| 60 | 'Exponential distributions work on time to occurrence; the time to occurrence (x) must be positive' |
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| 61 | ); |
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| 62 | } |
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| 63 | ||
| 64 | /** @var ImmutableNumber $e */ |
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| 65 | $e = Numbers::makeE(); |
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| 66 | ||
| 67 | /** @var ImmutableNumber $cdf */ |
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| 68 | $cdf = $one->subtract($e->pow($x->multiply($this->lambda)->multiply(-1))); |
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| 69 | ||
| 70 | return $cdf; |
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| 71 | ||
| 72 | } |
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| 73 | ||
| 74 | /** |
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| 75 | * @param $x |
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| @@ 80-101 (lines=22) @@ | ||
| 77 | * @return ImmutableNumber |
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| 78 | * @throws IntegrityConstraint |
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| 79 | */ |
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| 80 | public function pdf($x): ImmutableNumber |
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| 81 | { |
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| 82 | ||
| 83 | $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x); |
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| 84 | ||
| 85 | if (!$x->isPositive()) { |
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| 86 | throw new IntegrityConstraint( |
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| 87 | 'X must be positive', |
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| 88 | 'Provide a positive x', |
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| 89 | 'Exponential distributions work on time to occurrence; the time to occurrence (x) must be positive' |
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| 90 | ); |
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| 91 | } |
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| 92 | ||
| 93 | /** @var ImmutableNumber $e */ |
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| 94 | $e = Numbers::makeE(); |
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| 95 | ||
| 96 | /** @var ImmutableNumber $pdf */ |
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| 97 | $pdf = $this->lambda->multiply($e->pow($this->lambda->multiply(-1)->multiply($x))); |
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| 98 | ||
| 99 | return $pdf; |
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| 100 | ||
| 101 | } |
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| 102 | ||
| 103 | /** |
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| 104 | * @param $x1 |
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| @@ 96-114 (lines=19) @@ | ||
| 93 | * @throws IntegrityConstraint |
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| 94 | * @throws IncompatibleObjectState |
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| 95 | */ |
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| 96 | public function pmf($x): ImmutableNumber |
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| 97 | {
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| 98 | $x = Numbers::makeOrDont(Numbers::IMMUTABLE, $x); |
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| 99 | ||
| 100 | if (!$x->isNatural()) {
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| 101 | throw new IntegrityConstraint( |
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| 102 | 'Only integers are valid x values for Poisson distributions', |
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| 103 | 'Provide an integer value to calculate the PMF', |
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| 104 | 'Poisson distributions describe discrete occurrences; only integers are valid x values' |
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| 105 | ); |
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| 106 | } |
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| 107 | ||
| 108 | $e = Numbers::makeE(); |
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| 109 | ||
| 110 | /** @var ImmutableNumber $pmf */ |
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| 111 | $pmf = $this->lambda->pow($x)->multiply($e->pow($this->lambda->multiply(-1)))->divide($x->factorial()); |
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| 112 | ||
| 113 | return $pmf; |
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| 114 | } |
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| 115 | ||
| 116 | /** |
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| 117 | * @param int|float|DecimalInterface $x1 |
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