This class implements several numeric function with approximated results but with fast performances.
More...
|
| static uint8_t | sqrt (const uint8_t value) |
| | Returns the square root for values inside range [0, 2^8). More...
|
| |
| static uint8_t | sqrt (const uint16_t value) |
| | Returns the square root for values inside range [0, 2^16). More...
|
| |
| static uint16_t | sqrt (const uint32_t value) |
| | Returns the square root for values inside range [0, 2^17). More...
|
| |
| template<typename T > |
| static T | atan2 (const T y, const T x) |
| | Returns the approximated arc tangent with an error below one degree. More...
|
| |
| template<typename T , bool tHigherAccuracy> |
| static T | exp (T x) |
| | Returns the approximated exponential function exp(x) = e^x. More...
|
| |
|
| static const uint8_t * | sqrtLookup8 () |
| | Creates a lookup table for the sqrt function with range [0, 255]. More...
|
| |
| static const uint8_t * | sqrtLookup16 () |
| | Creates a lookup table for the sqrt function with range [0, 65,535]. More...
|
| |
| static const uint16_t * | sqrtLookup17 () |
| | Creates a lookup table for the sqrt function with range [0, 131,071]. More...
|
| |
This class implements several numeric function with approximated results but with fast performances.
◆ atan2()
template<typename T >
| static T Ocean::Approximation::atan2 |
( |
const T |
y, |
|
|
const T |
x |
|
) |
| |
|
static |
Returns the approximated arc tangent with an error below one degree.
- Parameters
-
| y | Y coordinate value, with range (-infinity, infinity), must not be zero if x is zero |
| x | X coordinate value, with range (-infinity, infinity), must not be zero if y is zero |
- Returns
- Approximated arc tangent in radian, with range [-PI, PI]
- Template Parameters
-
| T | The data type of the scalar, either 'float' or 'double' |
◆ exp()
template<typename T , bool tHigherAccuracy>
| T Ocean::Approximation::exp |
( |
T |
x | ) |
|
|
inlinestatic |
Returns the approximated exponential function exp(x) = e^x.
This function provides two accuracy modes.
The accuracy is as follows for an x86 CPU, within the value range [-1, 1]:
32 bit floating point values:
Lower accuracy: Median (p50) error: 0.00041, p99 error: 0.00498
Higher accuracy: Median (p50) error: 0.00008, p99 error: 0.00096
64 bit floating point values:
Lower accuracy: Median (p50) error: 0.00041, p99 error: 0.00498
Higher accuracy: Median (p50) error: 0.00003, p99 error: 0.00031
- Parameters
-
| x | The value for which exp(x) will be approximated, with range (-infinity, infinity) |
- Returns
- The approximated exponential value
- Template Parameters
-
| T | Data type of the provided value, either 'float' or 'double' |
| tHigherAccuracy | True, to approximate exp with higher accuracy; False, to get the lower accuracy |
◆ sqrt() [1/3]
| static uint8_t Ocean::Approximation::sqrt |
( |
const uint16_t |
value | ) |
|
|
static |
Returns the square root for values inside range [0, 2^16).
A lookup table with 2^16 = 65.536 bytes is used, which will be created before the first usage.
- Parameters
-
| value | The value to return the square root for, with range [0, 65535] |
- Returns
- Rounded square root
◆ sqrt() [2/3]
| static uint16_t Ocean::Approximation::sqrt |
( |
const uint32_t |
value | ) |
|
|
static |
Returns the square root for values inside range [0, 2^17).
Beware: No range check will be done for the given value. A lookup table with 2^16 * 2 = 131.072 bytes is used, which will be created before the first usage. Therefore, the resulting value does not have the best accuracy due to the reduces lookup table dimension.
- Parameters
-
| value | The value to return the square root for, with range [0, 131071] |
- Returns
- Rounded square root
◆ sqrt() [3/3]
| static uint8_t Ocean::Approximation::sqrt |
( |
const uint8_t |
value | ) |
|
|
static |
Returns the square root for values inside range [0, 2^8).
A lookup table with 2^8 = 256 bytes is used, which will be created before the first usage.
- Parameters
-
| value | The value to return the square root for, with range [0, 255] |
- Returns
- Rounded square root
◆ sqrtLookup16()
| static const uint8_t* Ocean::Approximation::sqrtLookup16 |
( |
| ) |
|
|
staticprotected |
Creates a lookup table for the sqrt function with range [0, 65,535].
- Returns
- Pointer to the static lookup table
◆ sqrtLookup17()
| static const uint16_t* Ocean::Approximation::sqrtLookup17 |
( |
| ) |
|
|
staticprotected |
Creates a lookup table for the sqrt function with range [0, 131,071].
- Returns
- Pointer to the static lookup table
◆ sqrtLookup8()
| static const uint8_t* Ocean::Approximation::sqrtLookup8 |
( |
| ) |
|
|
staticprotected |
Creates a lookup table for the sqrt function with range [0, 255].
- Returns
- Pointer to the static lookup table
The documentation for this class was generated from the following file:
1.9.1