WCSLIB 5.19.1

Data Fields
spxprm Struct Reference

Spectral variables and their derivatives. More...

`#include <spx.h>`

## Data Fields
double | restfrq
double | restwav
int | wavetype
int | velotype
double | freq
double | afrq
double | ener
double | wavn
double | vrad
double | wave
double | vopt
double | zopt
double | awav
double | velo
double | beta
double | dfreqafrq
double | dafrqfreq
double | dfreqener
double | denerfreq
double | dfreqwavn
double | dwavnfreq
double | dfreqvrad
double | dvradfreq
double | dfreqwave
double | dwavefreq
double | dfreqawav
double | dawavfreq
double | dfreqvelo
double | dvelofreq
double | dwavevopt
double | dvoptwave
double | dwavezopt
double | dzoptwave
double | dwaveawav
double | dawavwave
double | dwavevelo
double | dvelowave
double | dawavvelo
double | dveloawav
double | dvelobeta
double | dbetavelo
struct wcserr * | err
void * | padding

## Detailed Description

The spxprm struct contains the value of all spectral variables and their derivatives. It is used solely by specx() which constructs it from information provided via its function arguments.

This struct should be considered read-only, no members need ever be set nor should ever be modified by the user.

## Field Documentation

## ◆ restfrq

double spxprm::restfrq

(Returned) Rest frequency [Hz].

## ◆ restwav

double spxprm::restwav

(Returned) Rest wavelength [m].

## ◆ wavetype

int spxprm::wavetype

(Returned) True if wave types have been computed, and ...

## ◆ velotype

int spxprm::velotype

(Returned) ... true if velocity types have been computed; types are defined below.

If one or other of spxprm::restfrq and spxprm::restwav is given (non-zero) then all spectral variables may be computed. If both are given, restfrq is used. If restfrq and restwav are both zero, only wave characteristic xor velocity type spectral variables may be computed depending on the variable given. These flags indicate what is available.

## ◆ freq

double spxprm::freq

(Returned) Frequency [Hz] (wavetype).

## ◆ afrq

double spxprm::afrq

(Returned) Angular frequency [rad/s] (wavetype).

## ◆ ener

double spxprm::ener

(Returned) Photon energy [J] (wavetype).

## ◆ wavn

double spxprm::wavn

(Returned) Wave number [/m] (wavetype).

## ◆ vrad

double spxprm::vrad

(Returned) Radio velocity [m/s] (velotype).

## ◆ wave

double spxprm::wave

(Returned) Vacuum wavelength [m] (wavetype).

## ◆ vopt

double spxprm::vopt

(Returned) Optical velocity [m/s] (velotype).

## ◆ zopt

double spxprm::zopt

(Returned) Redshift [dimensionless] (velotype).

## ◆ awav

double spxprm::awav

(Returned) Air wavelength [m] (wavetype).

## ◆ velo

double spxprm::velo

(Returned) Relativistic velocity [m/s] (velotype).

## ◆ beta

double spxprm::beta

(Returned) Relativistic beta [dimensionless] (velotype).

## ◆ dfreqafrq

double spxprm::dfreqafrq

(Returned) Derivative of frequency with respect to angular frequency [/rad] (constant, ), and ...

## ◆ dafrqfreq

double spxprm::dafrqfreq

(Returned) ... vice versa [rad] (constant, , always available).

## ◆ dfreqener

double spxprm::dfreqener

(Returned) Derivative of frequency with respect to photon energy [/J/s] (constant, ), and ...

## ◆ denerfreq

double spxprm::denerfreq

(Returned) ... vice versa [Js] (constant, , Planck's constant, always available).

## ◆ dfreqwavn

double spxprm::dfreqwavn

(Returned) Derivative of frequency with respect to wave number [m/s] (constant, , the speed of light in vacuo), and ...

## ◆ dwavnfreq

double spxprm::dwavnfreq

(Returned) ... vice versa [s/m] (constant, , always available).

## ◆ dfreqvrad

double spxprm::dfreqvrad

(Returned) Derivative of frequency with respect to radio velocity [/m], and ...

## ◆ dvradfreq

double spxprm::dvradfreq

(Returned) ... vice versa [m] (wavetype && velotype).

## ◆ dfreqwave

double spxprm::dfreqwave

(Returned) Derivative of frequency with respect to vacuum wavelength [/m/s], and ...

## ◆ dwavefreq

double spxprm::dwavefreq

(Returned) ... vice versa [m s] (wavetype).

## ◆ dfreqawav

double spxprm::dfreqawav

(Returned) Derivative of frequency with respect to air wavelength, [/m/s], and ...

## ◆ dawavfreq

double spxprm::dawavfreq

(Returned) ... vice versa [m s] (wavetype).

## ◆ dfreqvelo

double spxprm::dfreqvelo

(Returned) Derivative of frequency with respect to relativistic velocity [/m], and ...

## ◆ dvelofreq

double spxprm::dvelofreq

(Returned) ... vice versa [m] (wavetype && velotype).

## ◆ dwavevopt

double spxprm::dwavevopt

(Returned) Derivative of vacuum wavelength with respect to optical velocity [s], and ...

## ◆ dvoptwave

double spxprm::dvoptwave

(Returned) ... vice versa [/s] (wavetype && velotype).

## ◆ dwavezopt

double spxprm::dwavezopt

(Returned) Derivative of vacuum wavelength with respect to redshift [m], and ...

## ◆ dzoptwave

double spxprm::dzoptwave

(Returned) ... vice versa [/m] (wavetype && velotype).

## ◆ dwaveawav

double spxprm::dwaveawav

(Returned) Derivative of vacuum wavelength with respect to air wavelength [dimensionless], and ...

## ◆ dawavwave

double spxprm::dawavwave

(Returned) ... vice versa [dimensionless] (wavetype).

## ◆ dwavevelo

double spxprm::dwavevelo

(Returned) Derivative of vacuum wavelength with respect to relativistic velocity [s], and ...

## ◆ dvelowave

double spxprm::dvelowave

(Returned) ... vice versa [/s] (wavetype && velotype).

## ◆ dawavvelo

double spxprm::dawavvelo

(Returned) Derivative of air wavelength with respect to relativistic velocity [s], and ...

## ◆ dveloawav

double spxprm::dveloawav

(Returned) ... vice versa [/s] (wavetype && velotype).

## ◆ dvelobeta

double spxprm::dvelobeta

(Returned) Derivative of relativistic velocity with respect to relativistic beta [m/s] (constant, , the speed of light in vacuo), and ...

## ◆ dbetavelo

double spxprm::dbetavelo

(Returned) ... vice versa [s/m] (constant, , always available).

## ◆ err

struct wcserr * spxprm::err

(Returned) If enabled, when an error status is returned, this struct contains detailed information about the error, see wcserr_enable().

## ◆ padding

void * spxprm::padding

(An unused variable inserted for alignment purposes only.)

Global variable: const char *spx_errmsg[] - Status return messages Error messages to match the status value returned from each function.