QuantityValue::getUncertaintyMargin() - Code Metrics - Inspection of "Merge pull request #122 from DataValues/fixcov" - DataValues/Number - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 946fba...596b16 )

by Marius

created 2018-10-31 11:57 UTC

QuantityValue::getUncertaintyMargin() A

↳ Parent: QuantityValue

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	1

Importance

Changes

Metric	Value
dl	0
loc	9
ccs	6
cts	6
cp	1
rs	9.9666
c	0
b	0
f	0
cc	1
nc	1
nop	0
crap	1

<?php

namespace DataValues;

use InvalidArgumentException;

/**
 * Class representing a quantity with associated unit and uncertainty interval.
 * The amount is stored as a @see DecimalValue object.
 *
 * @see UnboundedQuantityValue for quantities with unknown uncertainty interval.
 * For simple numeric amounts use @see NumberValue.
 *
 * @note UnboundedQuantityValue and QuantityValue both use the value type ID "quantity".
 * The fact that we use subclassing to model the bounded vs the unbounded case should be
 * considered an implementation detail.
 *
 * @since 0.1
 *
 * @license GPL-2.0+
 * @author Daniel Kinzler
 */
class QuantityValue extends UnboundedQuantityValue {

	/**
	 * The quantity's upper bound
	 *
	 * @var DecimalValue
	 */
	private $upperBound;

	/**
	 * The quantity's lower bound
	 *
	 * @var DecimalValue
	 */
	private $lowerBound;

	/**
	 * @since 0.1
	 *
	 * @param DecimalValue $amount
	 * @param string $unit A unit identifier. Must not be empty, use "1" for unit-less quantities.
	 * @param DecimalValue $upperBound The upper bound of the quantity, inclusive.
	 * @param DecimalValue $lowerBound The lower bound of the quantity, inclusive.
	 *
	 * @throws IllegalValueException
	 */
	public function __construct( DecimalValue $amount, $unit, DecimalValue $upperBound, DecimalValue $lowerBound ) {
		parent::__construct( $amount, $unit );

		if ( $lowerBound->compare( $amount ) > 0 ) {
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
			throw new IllegalValueException( '$lowerBound ' . $lowerBound->getValue() . ' must be <= $amount ' . $amount->getValue() );
		}

		if ( $upperBound->compare( $amount ) < 0 ) {
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
			throw new IllegalValueException( '$upperBound ' . $upperBound->getValue() . ' must be >= $amount ' . $amount->getValue() );
		}

		$this->upperBound = $upperBound;
		$this->lowerBound = $lowerBound;
	}

	/**
	 * Returns a QuantityValue representing the given amount.
	 * If no upper or lower bound is given, the amount is assumed to be absolutely exact,
	 * that is, the amount itself will be used as the upper and lower bound.
	 *
	 * This is a convenience wrapper around the constructor that accepts native values
	 * instead of DecimalValue objects.
	 *
	 * @note: if the amount or a bound is given as a string, the string must conform
	 * to the rules defined by @see DecimalValue.
	 *
	 * @since 0.1
	 *
	 * @param string|int|float|DecimalValue $amount
	 * @param string $unit A unit identifier. Must not be empty, use "1" for unit-less quantities.
	 * @param string|int|float|DecimalValue|null $upperBound
	 * @param string|int|float|DecimalValue|null $lowerBound
	 *
	 * @return self
	 * @throws IllegalValueException
	 */
	public static function newFromNumber( $amount, $unit = '1', $upperBound = null, $lowerBound = null ) {
		$amount = self::asDecimalValue( 'amount', $amount );
		$upperBound = self::asDecimalValue( 'upperBound', $upperBound, $amount );
		$lowerBound = self::asDecimalValue( 'lowerBound', $lowerBound, $amount );

		return new self( $amount, $unit, $upperBound, $lowerBound );
	}

	/**
	 * @see Serializable::serialize
	 *
	 * @since 0.1
	 *
	 * @return string
	 */
	public function serialize() {
		return serialize( [
			$this->amount,
			$this->unit,
			$this->upperBound,
			$this->lowerBound,
		] );
	}

	/**
	 * @see Serializable::unserialize
	 *
	 * @since 0.1
	 *
	 * @param string $data
	 */
	public function unserialize( $data ) {
		list( $amount, $unit, $upperBound, $lowerBound ) = unserialize( $data );
		$this->__construct( $amount, $unit, $upperBound, $lowerBound );
	}

	/**
	 * Returns this quantity's upper bound.
	 *
	 * @since 0.1
	 *
	 * @return DecimalValue
	 */
	public function getUpperBound() {
		return $this->upperBound;
	}

	/**
	 * Returns this quantity's lower bound.
	 *
	 * @since 0.1
	 *
	 * @return DecimalValue
	 */
	public function getLowerBound() {
		return $this->lowerBound;
	}

	/**
	 * Returns the size of the uncertainty interval.
	 * This can roughly be interpreted as "amount +/- uncertainty/2".
	 *
	 * The exact interpretation of the uncertainty interval is left to the concrete application or
	 * data point. For example, the uncertainty interval may be defined to be that part of a
	 * normal distribution that is required to cover the 95th percentile.
	 *
	 * @since 0.1
	 *
	 * @return float
	 */
	public function getUncertainty() {
		return $this->upperBound->getValueFloat() - $this->lowerBound->getValueFloat();
	}

	/**
	 * Returns a DecimalValue representing the symmetrical offset to be applied
	 * to the raw amount for a rough representation of the uncertainty interval,
	 * as in "amount +/- offset".
	 *
	 * The offset is calculated as max( amount - lowerBound, upperBound - amount ).
	 *
	 * @since 0.1
	 *
	 * @return DecimalValue
	 */
	public function getUncertaintyMargin() {
		$math = new DecimalMath();

		$lowerMargin = $math->sum( $this->amount, $this->lowerBound->computeComplement() );
		$upperMargin = $math->sum( $this->upperBound, $this->amount->computeComplement() );

		$margin = $math->max( $lowerMargin, $upperMargin );
		return $margin;
	}

	/**
	 * Returns the order of magnitude of the uncertainty as the exponent of
	 * last significant digit in the amount-string. The value returned by this
	 * is suitable for use with @see DecimalMath::roundToExponent().
	 *
	 * @example: if two digits after the decimal point are significant, this
	 * returns -2.
	 *
	 * @example: if the last two digits before the decimal point are insignificant,
	 * this returns 2.
	 *
	 * Note that this calculation assumes a symmetric uncertainty interval,
	 * and can be misleading.
	 *
	 * @since 0.1
	 *
	 * @return int
	 */
	public function getOrderOfUncertainty() {
		// the desired precision is given by the distance between the amount and
		// whatever is closer, the upper or lower bound.
		//TODO: use DecimalMath to avoid floating point errors!
		$amount = $this->amount->getValueFloat();
		$upperBound = $this->upperBound->getValueFloat();
		$lowerBound = $this->lowerBound->getValueFloat();
		$precision = min( $amount - $lowerBound, $upperBound - $amount );

		if ( $precision === 0.0 ) {
			// If there is no uncertainty, the order of uncertainty is a bit more than what we have digits for.
			return -strlen( $this->amount->getFractionalPart() );
		}

		// e.g. +/- 200 -> 2; +/- 0.02 -> -2
		// note: we really want floor( log10( $precision ) ), but have to account for
		// small errors made in the floating point operations above.
		// @todo: use bcmath (via DecimalMath) to avoid this if possible
		$orderOfUncertainty = floor( log10( $precision + 0.0000000005 ) );

		return (int)$orderOfUncertainty;
	}

	/**
	 * @see UnboundedQuantityValue::transform
	 *
	 * @param string $newUnit
	 * @param callable $transformation
	 * @param mixed [$args,...]
	 *
	 * @todo Should be factored out into a separate QuantityMath class.
	 *
	 * @throws InvalidArgumentException
	 * @return self
	 */
	public function transform( $newUnit, $transformation ) {
		if ( !is_callable( $transformation ) ) {
			throw new InvalidArgumentException( '$transformation must be callable.' );
		}

		if ( !is_string( $newUnit ) || $newUnit === '' ) {
			throw new InvalidArgumentException( '$newUnit must be a non-empty string. Use "1" for unit-less quantities.' );
		}

		// Apply transformation by calling the $transform callback.
		// The first argument for the callback is the DataValue to transform. In addition,
		// any extra arguments given for transform() are passed through.
		$args = func_get_args();
		array_shift( $args );

		$args[0] = $this->amount;
		$amount = call_user_func_array( $transformation, $args );

		$args[0] = $this->upperBound;
		$upperBound = call_user_func_array( $transformation, $args );

		$args[0] = $this->lowerBound;
		$lowerBound = call_user_func_array( $transformation, $args );

		// use a preliminary QuantityValue to determine the significant number of digits
		$transformed = new self( $amount, $newUnit, $upperBound, $lowerBound );
		$roundingExponent = $transformed->getOrderOfUncertainty();

		// apply rounding to the significant digits
		$math = new DecimalMath();

		$amount = $math->roundToExponent( $amount, $roundingExponent );
		$upperBound = $math->roundToExponent( $upperBound, $roundingExponent );
		$lowerBound = $math->roundToExponent( $lowerBound, $roundingExponent );

		return new self( $amount, $newUnit, $upperBound, $lowerBound );
	}

	public function __toString() {
		return $this->amount->getValue()
			. '[' . $this->lowerBound->getValue()
			. '..' . $this->upperBound->getValue()
			. ']'
			. ( $this->unit === '1' ? '' : $this->unit );
	}

	/**
	 * @see DataValue::getArrayValue
	 *
	 * @since 0.1
	 *
	 * @return array
	 */
	public function getArrayValue() {
		return [
			'amount' => $this->amount->getArrayValue(),
			'unit' => $this->unit,
			'upperBound' => $this->upperBound->getArrayValue(),
			'lowerBound' => $this->lowerBound->getArrayValue(),
		];
	}

}


1		<?php
2
3		namespace DataValues;
4
5		use InvalidArgumentException;
6
7		/**
8		* Class representing a quantity with associated unit and uncertainty interval.
9		* The amount is stored as a @see DecimalValue object.
10		*
11		* @see UnboundedQuantityValue for quantities with unknown uncertainty interval.
12		* For simple numeric amounts use @see NumberValue.
13		*
14		* @note UnboundedQuantityValue and QuantityValue both use the value type ID "quantity".
15		* The fact that we use subclassing to model the bounded vs the unbounded case should be
16		* considered an implementation detail.
17		*
18		* @since 0.1
19		*
20		* @license GPL-2.0+
21		* @author Daniel Kinzler
22		*/
23		class QuantityValue extends UnboundedQuantityValue {
24
25		/**
26		* The quantity's upper bound
27		*
28		* @var DecimalValue
29		*/
30		private $upperBound;
31
32		/**
33		* The quantity's lower bound
34		*
35		* @var DecimalValue
36		*/
37		private $lowerBound;
38
39		/**
40		* @since 0.1
41		*
42		* @param DecimalValue $amount
43		* @param string $unit A unit identifier. Must not be empty, use "1" for unit-less quantities.
44		* @param DecimalValue $upperBound The upper bound of the quantity, inclusive.
45		* @param DecimalValue $lowerBound The lower bound of the quantity, inclusive.
46		*
47		* @throws IllegalValueException
48		*/
49	34	public function __construct( DecimalValue $amount, $unit, DecimalValue $upperBound, DecimalValue $lowerBound ) {
50	34	parent::__construct( $amount, $unit );
51
52	32	if ( $lowerBound->compare( $amount ) > 0 ) {
		0 ignored issues – show Documentation introduced 2016-06-23 15:23 UTC by Report Bug Copy Issue Report `$amount` is of type `object<DataValues\DecimalValue>`, but the function expects a `object<self>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
53	1	throw new IllegalValueException( '$lowerBound ' . $lowerBound->getValue() . ' must be <= $amount ' . $amount->getValue() );
54		}
55
56	31	if ( $upperBound->compare( $amount ) < 0 ) {
		0 ignored issues – show Documentation introduced 2016-06-23 15:23 UTC by Report Bug Copy Issue Report `$amount` is of type `object<DataValues\DecimalValue>`, but the function expects a `object<self>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
57	1	throw new IllegalValueException( '$upperBound ' . $upperBound->getValue() . ' must be >= $amount ' . $amount->getValue() );
58		}
59
60	30	$this->upperBound = $upperBound;
61	30	$this->lowerBound = $lowerBound;
62	30	}
63
64		/**
65		* Returns a QuantityValue representing the given amount.
66		* If no upper or lower bound is given, the amount is assumed to be absolutely exact,
67		* that is, the amount itself will be used as the upper and lower bound.
68		*
69		* This is a convenience wrapper around the constructor that accepts native values
70		* instead of DecimalValue objects.
71		*
72		* @note: if the amount or a bound is given as a string, the string must conform
73		* to the rules defined by @see DecimalValue.
74		*
75		* @since 0.1
76		*
77		* @param string\|int\|float\|DecimalValue $amount
78		* @param string $unit A unit identifier. Must not be empty, use "1" for unit-less quantities.
79		* @param string\|int\|float\|DecimalValue\|null $upperBound
80		* @param string\|int\|float\|DecimalValue\|null $lowerBound
81		*
82		* @return self
83		* @throws IllegalValueException
84		*/
85	7	public static function newFromNumber( $amount, $unit = '1', $upperBound = null, $lowerBound = null ) {
86	7	$amount = self::asDecimalValue( 'amount', $amount );
87	7	$upperBound = self::asDecimalValue( 'upperBound', $upperBound, $amount );
88	7	$lowerBound = self::asDecimalValue( 'lowerBound', $lowerBound, $amount );
89
90	7	return new self( $amount, $unit, $upperBound, $lowerBound );
91		}
92
93		/**
94		* @see Serializable::serialize
95		*
96		* @since 0.1
97		*
98		* @return string
99		*/
100	9	public function serialize() {
101	9	return serialize( [
102	9	$this->amount,
103	9	$this->unit,
104	9	$this->upperBound,
105	9	$this->lowerBound,
106		] );
107		}
108
109		/**
110		* @see Serializable::unserialize
111		*
112		* @since 0.1
113		*
114		* @param string $data
115		*/
116	9	public function unserialize( $data ) {
117	9	list( $amount, $unit, $upperBound, $lowerBound ) = unserialize( $data );
118	9	$this->__construct( $amount, $unit, $upperBound, $lowerBound );
119	9	}
120
121		/**
122		* Returns this quantity's upper bound.
123		*
124		* @since 0.1
125		*
126		* @return DecimalValue
127		*/
128	19	public function getUpperBound() {
129	19	return $this->upperBound;
130		}
131
132		/**
133		* Returns this quantity's lower bound.
134		*
135		* @since 0.1
136		*
137		* @return DecimalValue
138		*/
139	19	public function getLowerBound() {
140	19	return $this->lowerBound;
141		}
142
143		/**
144		* Returns the size of the uncertainty interval.
145		* This can roughly be interpreted as "amount +/- uncertainty/2".
146		*
147		* The exact interpretation of the uncertainty interval is left to the concrete application or
148		* data point. For example, the uncertainty interval may be defined to be that part of a
149		* normal distribution that is required to cover the 95th percentile.
150		*
151		* @since 0.1
152		*
153		* @return float
154		*/
155	8	public function getUncertainty() {
156	8	return $this->upperBound->getValueFloat() - $this->lowerBound->getValueFloat();
157		}
158
159		/**
160		* Returns a DecimalValue representing the symmetrical offset to be applied
161		* to the raw amount for a rough representation of the uncertainty interval,
162		* as in "amount +/- offset".
163		*
164		* The offset is calculated as max( amount - lowerBound, upperBound - amount ).
165		*
166		* @since 0.1
167		*
168		* @return DecimalValue
169		*/
170	6	public function getUncertaintyMargin() {
171	6	$math = new DecimalMath();
172
173	6	$lowerMargin = $math->sum( $this->amount, $this->lowerBound->computeComplement() );
174	6	$upperMargin = $math->sum( $this->upperBound, $this->amount->computeComplement() );
175
176	6	$margin = $math->max( $lowerMargin, $upperMargin );
177	6	return $margin;
178		}
179
180		/**
181		* Returns the order of magnitude of the uncertainty as the exponent of
182		* last significant digit in the amount-string. The value returned by this
183		* is suitable for use with @see DecimalMath::roundToExponent().
184		*
185		* @example: if two digits after the decimal point are significant, this
186		* returns -2.
187		*
188		* @example: if the last two digits before the decimal point are insignificant,
189		* this returns 2.
190		*
191		* Note that this calculation assumes a symmetric uncertainty interval,
192		* and can be misleading.
193		*
194		* @since 0.1
195		*
196		* @return int
197		*/
198	22	public function getOrderOfUncertainty() {
199		// the desired precision is given by the distance between the amount and
200		// whatever is closer, the upper or lower bound.
201		//TODO: use DecimalMath to avoid floating point errors!
202	22	$amount = $this->amount->getValueFloat();
203	22	$upperBound = $this->upperBound->getValueFloat();
204	22	$lowerBound = $this->lowerBound->getValueFloat();
205	22	$precision = min( $amount - $lowerBound, $upperBound - $amount );
206
207	22	if ( $precision === 0.0 ) {
208		// If there is no uncertainty, the order of uncertainty is a bit more than what we have digits for.
209	4	return -strlen( $this->amount->getFractionalPart() );
210		}
211
212		// e.g. +/- 200 -> 2; +/- 0.02 -> -2
213		// note: we really want floor( log10( $precision ) ), but have to account for
214		// small errors made in the floating point operations above.
215		// @todo: use bcmath (via DecimalMath) to avoid this if possible
216	18	$orderOfUncertainty = floor( log10( $precision + 0.0000000005 ) );
217
218	18	return (int)$orderOfUncertainty;
219		}
220
221		/**
222		* @see UnboundedQuantityValue::transform
223		*
224		* @param string $newUnit
225		* @param callable $transformation
226		* @param mixed [$args,...]
227		*
228		* @todo Should be factored out into a separate QuantityMath class.
229		*
230		* @throws InvalidArgumentException
231		* @return self
232		*/
233	9	public function transform( $newUnit, $transformation ) {
234	9	if ( !is_callable( $transformation ) ) {
235		throw new InvalidArgumentException( '$transformation must be callable.' );
236		}
237
238	9	if ( !is_string( $newUnit ) \|\| $newUnit === '' ) {
239		throw new InvalidArgumentException( '$newUnit must be a non-empty string. Use "1" for unit-less quantities.' );
240		}
241
242		// Apply transformation by calling the $transform callback.
243		// The first argument for the callback is the DataValue to transform. In addition,
244		// any extra arguments given for transform() are passed through.
245	9	$args = func_get_args();
246	9	array_shift( $args );
247
248	9	$args[0] = $this->amount;
249	9	$amount = call_user_func_array( $transformation, $args );
250
251	9	$args[0] = $this->upperBound;
252	9	$upperBound = call_user_func_array( $transformation, $args );
253
254	9	$args[0] = $this->lowerBound;
255	9	$lowerBound = call_user_func_array( $transformation, $args );
256
257		// use a preliminary QuantityValue to determine the significant number of digits
258	9	$transformed = new self( $amount, $newUnit, $upperBound, $lowerBound );
259	9	$roundingExponent = $transformed->getOrderOfUncertainty();
260
261		// apply rounding to the significant digits
262	9	$math = new DecimalMath();
263
264	9	$amount = $math->roundToExponent( $amount, $roundingExponent );
265	9	$upperBound = $math->roundToExponent( $upperBound, $roundingExponent );
266	9	$lowerBound = $math->roundToExponent( $lowerBound, $roundingExponent );
267
268	9	return new self( $amount, $newUnit, $upperBound, $lowerBound );
269		}
270
271	1	public function __toString() {
272	1	return $this->amount->getValue()
273	1	. '[' . $this->lowerBound->getValue()
274	1	. '..' . $this->upperBound->getValue()
275	1	. ']'
276	1	. ( $this->unit === '1' ? '' : $this->unit );
277		}
278
279		/**
280		* @see DataValue::getArrayValue
281		*
282		* @since 0.1
283		*
284		* @return array
285		*/
286	14	public function getArrayValue() {
287		return [
288	14	'amount' => $this->amount->getArrayValue(),
289	14	'unit' => $this->unit,
290	14	'upperBound' => $this->upperBound->getArrayValue(),
291	14	'lowerBound' => $this->lowerBound->getArrayValue(),
292		];
293		}
294
295		}
296

DataValues / Number

Push — master ( 946fba...596b16 )

QuantityValue::getUncertaintyMargin() A

Complexity

Size

Duplication

Code Coverage

Importance

Duplication Side-by-Side

Filter issues like