mspass::seismic::SlownessVector Class Reference

Slowness vector object. More...

#include <SlownessVector.h>

Public Member Functions
	SlownessVector ()
	SlownessVector (const double ux0, const double uy0, const double az0=0.0)
	Fully parameterized constructor.
	SlownessVector (const SlownessVector &)
double	mag () const noexcept
double	azimuth () const noexcept
double	baz () const noexcept
SlownessVector &	operator= (const SlownessVector &parent)
	Standard assignment operator.
SlownessVector &	operator+= (const SlownessVector &other)
	Add another slowness vector to this one component-wise.
SlownessVector &	operator-= (const SlownessVector &other)
	Subtract another slowness vector from this one component-wise.
const SlownessVector	operator+ (const SlownessVector &other) const
	Return the component-wise sum of two slowness vectors.
const SlownessVector	operator- (const SlownessVector &other) const
	Return the component-wise difference of two slowness vectors.

Public Attributes
double	ux
double	uy

Friends
class	boost::serialization::access

Detailed Description

Slowness vector object.

Slowness vectors are a seismology concept used to describe wave propagation. A slowness vector points in the direction of propagation of a wave with a magnitude equal to the slowness (1/velocity) of propagation.

Author

Gary L. Pavlis

Constructor & Destructor Documentation

SlownessVector() [1/3]

mspass::seismic::SlownessVector::SlownessVector

(

)

Default constructor.

                               {
  ux = 0.0;
  uy = 0.0;
  azimuth0 = 0.0;
}

References ux, and uy.

SlownessVector() [2/3]

mspass::seismic::SlownessVector::SlownessVector	(	const double	ux0,
		const double	uy0,
		const double	az0 = 0.0
	)

Fully parameterized constructor.

A slowness vector is defined by it's components. There is one ambiguity, however, with a zero slowness vector. That is, normally direction of propagation is inferred from the vector azimuth. A zero slowness vector has physical significance (normal incidence) but presents and ambiguity in this regard. We use a defaulted az0 parameter to specify the azimuth that should be used if the magnitude of slowness vector is 0.

Parameters

ux0	- set x (EW) component to this value.
uy0	- set y (NS) component to this value.
az0	- use this as azimuth (radians) if this is a zero slowness vector (default 0.0)

                                                 {
  ux = ux0;
  uy = uy0;
  azimuth0 = az0;
}

References ux, and uy.

SlownessVector() [3/3]

mspass::seismic::SlownessVector::SlownessVector

(

const SlownessVector &

old

)

Copy constructor.

                                                        {
  ux = old.ux;
  uy = old.uy;
  azimuth0 = old.azimuth0;
}

References ux, and uy.

Member Function Documentation

azimuth()

double mspass::seismic::SlownessVector::azimuth ( ) const

noexcept

Returns the propagation direction defined by a slowness vector. Azimuth is a direction clockwise from north in the standard geographic convention. Value returned is in radians.

                                              {
  if (this->mag() <= FLT_EPSILON)
    return (azimuth0);
  double phi;
  phi = M_PI_2 - atan2(uy, ux);
  if (phi > M_PI)
    return (phi - 2.0 * M_PI);
  else if (phi < -M_PI)
    return (phi + 2.0 * M_PI);
  else
    return (phi);
}

References mag(), ux, and uy.

baz()

double mspass::seismic::SlownessVector::baz ( ) const

noexcept

Returns the back azimuth direction defined by a slowness vector. A back azimuth is 180 degrees away from the direction of propagation and points along the great circle path directed back to the source point from a given position. The value returned is in radians.

                                          {
  double phi;
  if (this->mag() <= FLT_EPSILON)
    phi = M_PI - azimuth0;
  else
    phi = 3.0 * M_PI_2 - atan2(uy, ux);
  if (phi > M_PI)
    return (phi - 2.0 * M_PI);
  else if (phi < -M_PI)
    return (phi + 2.0 * M_PI);
  else
    return (phi);
}

References mag(), ux, and uy.

mag()

double mspass::seismic::SlownessVector::mag ( ) const

noexcept

Computes the magntitude of the slowness vector. Value returned is in units of seconds/kilometer.

{ return (hypot(ux, uy)); }

References ux, and uy.

operator+()

const SlownessVector mspass::seismic::SlownessVector::operator+

(

const SlownessVector &

other

)

const

Return the component-wise sum of two slowness vectors.

                                                           {
  SlownessVector result(*this);
  result += other;
  return result;
}

operator+=()

SlownessVector & mspass::seismic::SlownessVector::operator+=

(

const SlownessVector &

other

)

Add another slowness vector to this one component-wise.

                                                                      {
  ux += other.ux;
  uy += other.uy;
  return (*this);
}

References ux, and uy.

operator-()

const SlownessVector mspass::seismic::SlownessVector::operator-

(

const SlownessVector &

other

)

const

Return the component-wise difference of two slowness vectors.

                                                           {
  SlownessVector result(*this);
  result -= other;
  return result;
}

operator-=()

SlownessVector & mspass::seismic::SlownessVector::operator-=

(

const SlownessVector &

other

)

Subtract another slowness vector from this one component-wise.

                                                                      {
  ux -= other.ux;
  uy -= other.uy;
  return (*this);
}

References ux, and uy.

operator=()

SlownessVector & mspass::seismic::SlownessVector::operator=

(

const SlownessVector &

parent

)

Standard assignment operator.

                                                                      {
  if (this != &parent) {
    ux = parent.ux;
    uy = parent.uy;
    azimuth0 = parent.azimuth0;
  }
  return (*this);
}

References ux, and uy.

Member Data Documentation

ux

double mspass::seismic::SlownessVector::ux

East-west component of slowness vector.

uy

double mspass::seismic::SlownessVector::uy

North-south component of slowness vector.

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The documentation for this class was generated from the following files:

• /home/runner/work/mspass/mspass/cxx/include/mspass/seismic/SlownessVector.h
• /home/runner/work/mspass/mspass/cxx/src/lib/seismic/SlownessVector.cc