Class: Qnum
dg.Qnum
A set of static methods for working with qualified numbers. The internal representation of a qualified number is a regular double precision floating point number (IEEE 754), except the two least significant bits in mantissa are reserved for holding the qualifier ([LESS], [EXACT], [GREATER]).
The advantage of that representation is that the standard arithmetic operations could be performed directly on the number, without unpacking it. This is especially important for batch operations such as aggregation or sorting. While there is a loss of precision, it is rather insignificant (50 bits for storing mantissa instead of 52), which makes perfect sense considering that qualified numbers represent imprecise measurements.
Use [create], [getValue], and [getQ] methods for packing/unpacking.
Constructors
constructor
• new Qnum()
Methods
create
▸ Static create(value, q?): number
Creates a QNum value out of the [value] and qualifier [q].
Parameters
| Name | Type | Default value |
|---|---|---|
value | number | undefined |
q | number | QNUM_EXACT |
Returns
number
Defined in
exact
▸ Static exact(x): number
Parameters
| Name | Type |
|---|---|
x | number |
Returns
number
Defined in
getQ
▸ Static getQ(x): number
Extracts the qualifier (QNUM_LESS, QNUM_EXACT, QNUM_GREATER). See also getValue
Parameters
| Name | Type |
|---|---|
x | number |
Returns
number
Defined in
getValue
▸ Static getValue(x): number
Extracts the value from x, stripping the qualifier . See also getQ
Parameters
| Name | Type |
|---|---|
x | number |
Returns
number
Defined in
greater
▸ Static greater(x): number
Parameters
| Name | Type |
|---|---|
x | number |
Returns
number
Defined in
less
▸ Static less(x): number
Parameters
| Name | Type |
|---|---|
x | number |
Returns
number
Defined in
parse
▸ Static parse(s): number
Parses a string into a qualified number.
Parameters
| Name | Type |
|---|---|
s | string |
Returns
number
Defined in
qualifier
▸ Static qualifier(x): string
Returns the string representation of the qualifier.
Parameters
| Name | Type |
|---|---|
x | number |
Returns
string
Defined in
toString
▸ Static toString(x): string
Converts a qualified number to a string representation.
Parameters
| Name | Type |
|---|---|
x | number |
Returns
string