mspass::seismic::SlownessVector Class Reference

Slowness vector object.
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#include <SlownessVector.h>

Public Member Functions
	SlownessVector ()
	SlownessVector (const double ux0, const double uy0, const double az0=0.0)
	Fully parameterized constructor. More...
	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)
SlownessVector &	operator-= (const SlownessVector &other)
const SlownessVector	operator+ (const SlownessVector &other) const
const SlownessVector	operator- (const SlownessVector &other) const

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.

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