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# qwt_math.h File Reference

## Detailed Description

A set of mathematical routines.

Definition in file qwt_math.h.

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## Defines
#define | LOG10_2 0.30102999566398119802
#define | LOG10_3 0.47712125471966243540
#define | LOG10_5 0.69897000433601885749
#define | M_2PI 6.28318530717958623200
#define | LOG_MIN 1.0e-100
#define | LOG_MAX 1.0e100
#define | M_E 2.7182818284590452354
#define | M_LOG2E 1.4426950408889634074
#define | M_LN2 0.69314718055994530942
#define | M_LN10 2.30258509299404568402
#define | M_PI 3.14159265358979323846
#define | M_PI_2 1.57079632679489661923
#define | M_PI_4 0.78539816339744830962
#define | M_1_PI 0.31830988618379067154
#define | M_2_PI 0.63661977236758134308
#define | M_2_SQRTPI 1.12837916709551257390
#define | M_SQRT2 1.41421356237309504880
#define | M_SQRT1_2 0.70710678118654752440
#define | qwtMax QMAX
#define | qwtMin QMIN
#define | qwtAbs QABS
#define | qwtInt qRound
## Functions
QWT_EXPORT double | qwtCeil125 (double x)
QWT_EXPORT double | qwtFloor125 (double x)
QWT_EXPORT double | qwtGetMin (double *array, int size)
QWT_EXPORT double | qwtGetMax (double *array, int size)
QWT_EXPORT void | qwtTwistArray (double *array, int size)
QWT_EXPORT int | qwtChkMono (double *array, int size)
QWT_EXPORT void | qwtLinSpace (double *array, int size, double xmin, double xmax)
QWT_EXPORT void | qwtLogSpace (double *array, int size, double xmin, double xmax)
template<class T> int | qwtSign (const T &x)
template<class T> T | qwtSqr (const T &x)
template<class T> void | qwtCopyArray (T *dest, T *src, int n)
template<class T> void | qwtShiftArray (T *arr, int size, int di)
template<class T> void | qwtSwap (T &x1, T &x2)
template<class T> void | qwtSort (const T &x1, const T &x2, T &xmin, T &xmax)
template<class T> void | qwtSort (T &x1, T &x2)
template<class T> T | qwtLim (const T &x, const T &x1, const T &x2)
QPoint | qwtPolar2Pos (const QPoint &center, double radius, double angle)
QPoint | qwtDegree2Pos (const QPoint &center, double radius, double angle)

## Define Documentation

#define LOG_MAX 1.0e100

| Maximum value for logarithmic scales. Definition at line 46 of file qwt_math.h. Referenced by QwtAutoScale::setRange(), and QwtAutoScale::setReference().

#define LOG_MIN 1.0e-100

| Mininum value for logarithmic scales. Definition at line 41 of file qwt_math.h. Referenced by QwtAutoScale::setRange(), and QwtAutoScale::setReference().

## Function Documentation

QWT_EXPORT double qwtCeil125 | ( | double | x | ) |

  | Find the smallest value out of {1,2,5}*10^n with an integer number n which is greater than or equal to x. Parameters:
  | x | Input value
Definition at line 56 of file qwt_math.cpp.

QWT_EXPORT int qwtChkMono | ( | double * | array,
|  | int | size
| ) |

  | Checks if an array is a strictly monotonic sequence. Parameters:
  | array | Pointer to an array
  | size | Size of the array
Returns: 0 sequence is not strictly monotonic 1 sequence is strictly monotonically increasing -1 sequence is strictly monotonically decreasing Definition at line 119 of file qwt_math.cpp.

template<class T>
void qwtCopyArray | ( | T * | dest,
|  | T * | src,
|  | int | n
| ) |

  | Copy an array into another. Parameters:
  | dest | Destination
  | src | Source
  | n | Number of elements
Definition at line 142 of file qwt_math.h. Referenced by qwtShiftArray().

QWT_EXPORT double qwtFloor125 | ( | double | x | ) |

  | Find the largest value out of {1,2,5}*10^n with an integer number n which is smaller than or equal to x. Parameters:
  | x | Input value
Definition at line 85 of file qwt_math.cpp.

QWT_EXPORT double qwtGetMax | ( | double * | array,
|  | int | size
| ) |

  | Find the largest value in an array. Parameters:
  | array | Pointer to an array
  | size | Array size
Definition at line 37 of file qwt_math.cpp.

QWT_EXPORT double qwtGetMin | ( | double * | array,
|  | int | size
| ) |

  | Find the smallest value in an array. Parameters:
  | array | Pointer to an array
  | size | Array size
Definition at line 19 of file qwt_math.cpp.

template<class T>
T qwtLim | ( | const T & | x,
|  | const T & | x1,
|  | const T & | x2
| ) |

  | Limit a value to fit into a specified interval. Parameters:
  | x | Input value
  | x1 | First interval boundary
  | x2 | Second interval boundary
Definition at line 245 of file qwt_math.h. Referenced by QwtArrowButton::QwtArrowButton(), QwtScaleDraw::setAngleRange(), QwtDblRange::setRange(), QwtWheel::setTickCnt(), QwtWheel::setTotalAngle(), QwtWheel::setViewAngle(), and QwtCurve::verifyRange().

QWT_EXPORT void qwtLinSpace | ( | double * | array,
|  | int | size,
|  | double | xmin,
|  | double | xmax
| ) |

  | Create an array of equally spaced values. Parameters:
  | array | Where to put the values
  | size | Size of the array
  | xmin | Value associated with index 0
  | xmax | Value associated with index (size-1)
Definition at line 161 of file qwt_math.cpp.

QWT_EXPORT void qwtLogSpace | ( | double * | array,
|  | int | size,
|  | double | xmin,
|  | double | xmax
| ) |

  | Create an array of logarithmically equally spaced values. Parameters:
  | array | Where to put the values
  | size | Size of the array
  | xmin | Value associated with index 0
  | xmax | Value associated with index (size-1)
Definition at line 189 of file qwt_math.cpp.

template<class T>
void qwtShiftArray | ( | T * | arr,
|  | int | size,
|  | int | di
| ) |

  | Shift an array by a specified number of positions. Parameters:
  | arr | Pointer to an array
  | size | Number of elements
  | di | Number of positions. A positive number shifts right, a negative number shifts left.
Definition at line 157 of file qwt_math.h. References qwtCopyArray().

template<class T>
int qwtSign | ( | const T & | x | ) |

| Return the sign. Definition at line 118 of file qwt_math.h.

template<class T>
void qwtSort | ( | T & | x1,
|  | T & | x2
| ) |

| Sort two values in ascending order. Definition at line 226 of file qwt_math.h. Referenced by QwtCurve::verifyRange().

template<class T>
void qwtSort | ( | const T & | x1,
|  | const T & | x2,
|  | T & | xmin,
|  | T & | xmax
| ) |

  | Sort two values in ascending order. Parameters:
  | x1 | First input value
  | x2 | Second input value
  | xmax | Greater value
  | xmin | Smaller value
Definition at line 207 of file qwt_math.h.

template<class T>
T qwtSqr | ( | const T & | x | ) |

| Return the square of a number. Definition at line 130 of file qwt_math.h. Referenced by QwtPlot::closestCurve(), QwtPlot::closestMarker(), and QwtCurve::drawSpline().

template<class T>
void qwtSwap | ( | T & | x1,
|  | T & | x2
| ) |

| Swap two values. Definition at line 190 of file qwt_math.h.

QWT_EXPORT void qwtTwistArray | ( | double * | array,
|  | int | size
| ) |

  | Invert the order of array elements. Parameters:
  | array | Pointer to an array
  | size | Size of the array
Definition at line 141 of file qwt_math.cpp.