GasAbsLookup Class Reference

An absorption lookup table. More...

#include <gas_abs_lookup.h>

Collaboration diagram for GasAbsLookup:

List of all members.

Public Member Functions

GasAbsLookup ()

void Adapt (const ArrayOfArrayOfSpeciesTag &current_species, ConstVectorView current_f_grid)

Adapt lookup table to current calculation.

void Extract (Matrix &sga, const Index &p_interp_order, const Index &t_interp_order, const Index &h2o_interp_order, const Index &f_index, const Numeric &p, const Numeric &T, ConstVectorView abs_vmrs) const

Extract scalar gas absorption coefficients from the lookup table.

void GetFgrid (Vector &f) const

void GetPgrid (Vector &p) const

Private Attributes

ArrayOfArrayOfSpeciesTag species

The species tags for which the table is valid.

ArrayOfIndex nonlinear_species

The species tags with non-linear treatment.

Vector f_grid

The frequency grid [Hz].

Vector p_grid

The pressure grid for the table [Pa].

Vector log_p_grid

The natural log of the pressure grid.

Matrix vmrs_ref

The reference VMR profiles.

Vector t_ref

The reference temperature profile [K].

Vector t_pert

The vector of temperature perturbations [K].

Vector nls_pert

The vector of perturbations for the VMRs of the nonlinear species.

Tensor4 xsec

Absorption cross sections.

Friends

void xml_read_from_stream (istream &is_xml, GasAbsLookup &gal, bifstream *pbifs)

Reads GasAbsLookup from XML input stream.

void xml_write_to_stream (ostream &os_xml, const GasAbsLookup &gal, bofstream *pbofs, const String &name)

Writes GasAbsLookup to XML output stream.

void abs_lookupCreate (GasAbsLookup &abs_lookup, Index &abs_lookup_is_adapted, const ArrayOfArrayOfSpeciesTag &abs_species, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfArrayOfSpeciesTag &abs_nls, const Vector &f_grid, const Vector &abs_p, const Matrix &abs_vmrs, const Vector &abs_t, const Vector &abs_t_pert, const Vector &abs_nls_pert, const Vector &abs_n2, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters)

WORKSPACE METHOD: abs_lookupCreate.

Numeric calc_lookup_error (const GasAbsLookup &al, const Index &abs_p_interp_order, const Index &abs_t_interp_order, const Index &abs_nls_interp_order, const bool ignore_errors, const Vector &abs_n2, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters, const Numeric &local_p, const Numeric &local_t, const Vector &local_vmrs)

Compare lookup and LBL calculation.

void abs_lookupTestAccuracy (const GasAbsLookup &abs_lookup, const Index &abs_lookup_is_adapted, const Index &abs_p_interp_order, const Index &abs_t_interp_order, const Index &abs_nls_interp_order, const Vector &abs_n2, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters)

WORKSPACE METHOD: abs_lookupTestAccuracy.

Detailed Description

An absorption lookup table.

This class holds an absorption lookup table, as well as all information that is necessary to use the table to extract absorption. Extraction routines are implemented as member functions.

Definition at line 43 of file gas_abs_lookup.h.

Constructor & Destructor Documentation

GasAbsLookup::GasAbsLookup ( ) [inline]

Definition at line 45 of file gas_abs_lookup.h.

Member Function Documentation

void GasAbsLookup::Adapt	(	const ArrayOfArrayOfSpeciesTag &	current_species,
		ConstVectorView	current_f_grid
	)

Adapt lookup table to current calculation.

This method has the following tasks:

1. Find and remember the indices of the current species in the lookup table. At the same time verify that each species is included in the table exactly once.

2. Find and remember the frequencies of the current calculation in the lookup table. At the same time verify that all frequencies are included and that no frequency occurs twice.

3. Use the species and frequency index lists to build the new lookup table.

4. Replace original table by the new one.

5. Initialize log_p_grid.

The method is intended to be called only once per ARTS job, more or less directly from a corresponding workspace method. Therefore, runtime errors are thrown, rather than assertions, if something is wrong.

Parameters:

	current_species	The list of species for the current calculation.
	current_f_grid	The list of frequencies for the current calculation.

Date:: 2002-12-12

Definition at line 117 of file gas_abs_lookup.cc.

References chk_contains(), chk_if_decreasing(), chk_if_in_range(), chk_if_increasing(), chk_matrix_ncols(), chk_matrix_nrows(), chk_size(), chk_vector_length(), f_grid, find_new_grid_in_old_grid(), get_tag_group_name(), is_unique(), joker, log_p_grid, ConstTensor4View::nbooks(), ConstTensor4View::ncols(), ConstVectorView::nelem(), Array< base >::nelem(), nls_pert, nonlinear_species, out2, out3, p_grid, Tensor4::resize(), Matrix::resize(), Vector::resize(), species, t_pert, t_ref, transform(), vmrs_ref, and xsec.

Referenced by abs_lookupAdapt().

void GasAbsLookup::Extract	(	Matrix &	sga,
		const Index &	p_interp_order,
		const Index &	t_interp_order,
		const Index &	h2o_interp_order,
		const Index &	f_index,
		const Numeric &	p,
		const Numeric &	T,
		ConstVectorView	abs_vmrs
	)			const

Extract scalar gas absorption coefficients from the lookup table.

This carries out a simple interpolation in temperature and pressure. The interpolated value is then scaled by the ratio between actual VMR and reference VMR. In the case of nonlinear species the interpolation goes also over H2O VMR.

All input parameters (f_index, p, T, VMRs for non-linear species) must be in the range coverd by the table. Violation will result in a runtime error. Those checks are here, because they are a bit difficult to make outside, due to the irregularity of the grids. Otherwise there are no runtime checks in this function, only assertions. This is, because the function is called many times inside the RT calculation.

In this case pressure is not an altitude coordinate, so we are free to choose the type of interpolation that gives lowest interpolation errors or is easiest. I tested both linear and log p interpolation with the result that log p interpolation is slightly better, so that is used.

Return values:

sga

A Matrix with scalar gas absorption coefficients [1/m]. Dimension is adjusted automatically to either [1,n_species] or [n_f_grid,n_species]!

Parameters:

	f_index	The frequency index. If this is >=0, it means that absorption for this frequency will be extracted. (The leading dimension of sga will be 1.) If this is <0, it means that absorption for ALL frequencies is extracted. (The leading dimension of sga will be n_f_grid.)
	p	The pressures [Pa].
	T	The temperature [K].
	abs_vmrs	The VMRs [absolute number]. Dimension: [species].

Date:: 2002-09-20, 2003-02-22, 2007-05-22

Author:: Stefan Buehler

Definition at line 509 of file gas_abs_lookup.cc.

References DEBUG_ONLY, f_grid, find_first_species_tg(), gridpos_poly(), GridPosPoly::idx, interpweights(), is_size(), joker, log_p_grid, ConstVectorView::nelem(), Array< base >::nelem(), nls_pert, nonlinear_species, ConstTensor4View::npages(), number_density(), p_grid, Matrix::resize(), species, species_index_from_species_name(), t_pert, t_ref, vmrs_ref, and xsec.

Referenced by abs_scalar_gasExtractFromLookup(), and calc_lookup_error().

void GasAbsLookup::GetFgrid ( Vector & f ) const

Definition at line 1059 of file gas_abs_lookup.cc.

References f_grid, ConstVectorView::nelem(), and Vector::resize().

Referenced by f_gridFromGasAbsLookup().

void GasAbsLookup::GetPgrid ( Vector & p ) const

Definition at line 1066 of file gas_abs_lookup.cc.

References ConstVectorView::nelem(), p_grid, and Vector::resize().

Referenced by p_gridFromGasAbsLookup().

Friends And Related Function Documentation

void xml_read_from_stream	(	istream &	is_xml,
		GasAbsLookup &	gal,
		bifstream *	pbifs
	)			`[friend]`

Reads GasAbsLookup from XML input stream.

Parameters:

	is_xml	XML Input stream
	gal	GasAbsLookup return value
	pbifs	Pointer to binary input stream. NULL in case of ASCII file.

Definition at line 58 of file xml_io_compound_types.cc.

void xml_write_to_stream	(	ostream &	os_xml,
		const GasAbsLookup &	gal,
		bofstream *	pbofs,
		const String &	name
	)			`[friend]`

Writes GasAbsLookup to XML output stream.

Parameters:

	os_xml	XML Output stream
	gal	GasAbsLookup
	pbofs	Pointer to binary file stream. NULL for ASCII output.
	name	Optional name attribute

Definition at line 90 of file xml_io_compound_types.cc.

void abs_lookupCreate	(	GasAbsLookup &	abs_lookup,
		Index &	abs_lookup_is_adapted,
		const ArrayOfArrayOfSpeciesTag &	abs_species,
		const ArrayOfArrayOfLineRecord &	abs_lines_per_species,
		const ArrayOfLineshapeSpec &	abs_lineshape,
		const ArrayOfArrayOfSpeciesTag &	abs_nls,
		const Vector &	f_grid,
		const Vector &	abs_p,
		const Matrix &	abs_vmrs,
		const Vector &	abs_t,
		const Vector &	abs_t_pert,
		const Vector &	abs_nls_pert,
		const Vector &	abs_n2,
		const ArrayOfString &	abs_cont_names,
		const ArrayOfString &	abs_cont_models,
		const ArrayOfVector &	abs_cont_parameters
	)			`[friend]`

WORKSPACE METHOD: abs_lookupCreate.

Creates a gas absorption lookup table.

The lookup table stores absorption cross-sections as a function of pressure. Additionally, absorption can be stored as a function of temperature for temperature perturbations from a reference profile.

Additionally, absorption can be stored as a function of water vapor VMR perturbations from a reference profile. The variable *abs_nls* specifies, for which species water vapor perturbations should be generated.

Note, that the absorbing gas can be any gas, but the perturbing gas is always H2O.

In contrast to other absorption functions, this method does not use the input variable *abs_h2o*. This is because *abs_h2o* has to be set interally to allow perturbations. If there are more than one H2O species, the first is assumed to be the main one.

Author:: Stefan Buehler

Parameters:

`[out]`	abs_lookup	WS Output
`[out]`	abs_lookup_is_adapted	WS Output
`[in]`	abs_species	WS Input
`[in]`	abs_lines_per_species	WS Input
`[in]`	abs_lineshape	WS Input
`[in]`	abs_nls	WS Input
`[in]`	f_grid	WS Input
`[in]`	abs_p	WS Input
`[in]`	abs_vmrs	WS Input
`[in]`	abs_t	WS Input
`[in]`	abs_t_pert	WS Input
`[in]`	abs_nls_pert	WS Input
`[in]`	abs_n2	WS Input
`[in]`	abs_cont_names	WS Input
`[in]`	abs_cont_models	WS Input
`[in]`	abs_cont_parameters	WS Input

Definition at line 58 of file m_abs_lookup.cc.

Numeric calc_lookup_error	(	const GasAbsLookup &	al,
		const Index &	abs_p_interp_order,
		const Index &	abs_t_interp_order,
		const Index &	abs_nls_interp_order,
		const bool	ignore_errors,
		const Vector &	abs_n2,
		const ArrayOfArrayOfLineRecord &	abs_lines_per_species,
		const ArrayOfLineshapeSpec &	abs_lineshape,
		const ArrayOfString &	abs_cont_names,
		const ArrayOfString &	abs_cont_models,
		const ArrayOfVector &	abs_cont_parameters,
		const Numeric &	local_p,
		const Numeric &	local_t,
		const Vector &	local_vmrs
	)			`[friend]`

Compare lookup and LBL calculation.

This is a helper function used by abs_lookupTestAccuracy. It takes local p, T, and VMR conditions, performs lookup table extraction and line by line absorption calculation, and compares the difference.

Parameters:

	al	Lookup table
	abs_p_interp_order	Pressure interpolation order.
	abs_t_interp_order	Temperature interpolation order.
	abs_nls_interp_order	H2O interpolation order.
	ignore_errors	If true, we ignore runtime errors in lookup table extraction. This is handy, because in some cases it is not easy to make sure that all local conditions are inside the valid range for the lookup table.
	local_p
	local_t
	local_vmrs

Returns:: The maximum of the absolute value of the relative difference between lookup and LBL, in percent. Or -1 if the case should be ignored according to the "ignore_errors" flag.

Definition at line 2044 of file m_abs_lookup.cc.

void abs_lookupTestAccuracy	(	const GasAbsLookup &	abs_lookup,
		const Index &	abs_lookup_is_adapted,
		const Index &	abs_p_interp_order,
		const Index &	abs_t_interp_order,
		const Index &	abs_nls_interp_order,
		const Vector &	abs_n2,
		const ArrayOfArrayOfLineRecord &	abs_lines_per_species,
		const ArrayOfLineshapeSpec &	abs_lineshape,
		const ArrayOfString &	abs_cont_names,
		const ArrayOfString &	abs_cont_models,
		const ArrayOfVector &	abs_cont_parameters
	)			`[friend]`

WORKSPACE METHOD: abs_lookupTestAccuracy.

Test accuracy of absorption lookup table.

Explicitly compare absorption from the lookup table with line-by-line calculations for strategically selected conditions (in-between the lookup table grid points).

Produces no workspace output, only output to the output streams.

Author:: Stefan Buehler

Parameters:

`[in]`	abs_lookup	WS Input
`[in]`	abs_lookup_is_adapted	WS Input
`[in]`	abs_p_interp_order	WS Input
`[in]`	abs_t_interp_order	WS Input
`[in]`	abs_nls_interp_order	WS Input
`[in]`	abs_n2	WS Input
`[in]`	abs_lines_per_species	WS Input
`[in]`	abs_lineshape	WS Input
`[in]`	abs_cont_names	WS Input
`[in]`	abs_cont_models	WS Input
`[in]`	abs_cont_parameters	WS Input

Definition at line 2153 of file m_abs_lookup.cc.

Member Data Documentation

ArrayOfArrayOfSpeciesTag GasAbsLookup::species [private]

The species tags for which the table is valid.

Definition at line 136 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), calc_lookup_error(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

ArrayOfIndex GasAbsLookup::nonlinear_species [private]

The species tags with non-linear treatment.

This is the list of species for which the H2O VMR should be varied when calculating the lookup table. This must be inside the range of species. If nonlinear_species is an empty vector, it means that all species should be treated linearly. (No absorption for perturbed species profiles is stored.)

Definition at line 145 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::f_grid [private]

The frequency grid [Hz].

Must be sorted in ascending order.

Definition at line 149 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), Adapt(), calc_lookup_error(), Extract(), GetFgrid(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::p_grid [private]

The pressure grid for the table [Pa].

Must be sorted in decreasing order.

Definition at line 153 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), GetPgrid(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::log_p_grid [private]

The natural log of the pressure grid.

This is not stored with the table, it is calculated by the abs_lookupAdapt method.

We are interpolating the cross sections in log(p). Storing this with the table avoids having to calculate it over and over again.

Definition at line 161 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), and Extract().

Matrix GasAbsLookup::vmrs_ref [private]

The reference VMR profiles.

The VMRs for all species, associated with p_grid. Dimension: [n_species, n_p_grid]. These VMRs are needed to scale the absorption coefficient to other VMRs. We are never working with "absorption cross-sections", always with real absorption coefficients, so we have to remember the associated VMR values.

Physical unit: Absolute value.

Definition at line 171 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::t_ref [private]

The reference temperature profile [K].

This is a temperature profile. The dimension must be the same as p_grid.

Definition at line 176 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::t_pert [private]

The vector of temperature perturbations [K].

This can have any number of elements. Example: [-20,-10,0,10,20]. The actual temperatures for which absorption is stored are t_ref + t_pert for each level. The reference temperature itself should normally also be included, hence t_pert should always include 0. Must be sorted in ascending order!

The vector t_pert may be an empty vector (nelem()=0), which marks the special case that no interpolation in temperature should be done. If t_pert is not empty, you will get an error message if you try to extract absorption for temperatures outside the range of t_pert.

Definition at line 190 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

Vector GasAbsLookup::nls_pert [private]

The vector of perturbations for the VMRs of the nonlinear species.

These apply to all the species that have been set as nonlinear_species.

Fractional units are used! Example: [0,.5,1,10,100], meaning from VMR 0 to 100 times the profile given in abs_vmrs. The reference value should normally be included, hence nls_pert should always include the value 1.

If nonlinear_species is an empty vector, it means that there are no nonlinear species. Then nls_pert must also be an empty vector.

Definition at line 205 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), abs_lookupTestAccuracy(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

Tensor4 GasAbsLookup::xsec [private]

Absorption cross sections.

Physical unit: m^2

Attention:: We want to interpolate these beasts in pressure. To keep interpolation errors small it is better to store cross-sections, not coefficients. The absorption coefficient alpha is given by alpha = xsec * n, where n is the number density.

Dimension: [ a, b, c, d ]

Simplest case (no temperature perturbations, no vmr perturbations):
a = 1
b = n_species
c = n_f_grid
d = n_p_grid

Standard case (temperature perturbations, but no vmr perturbations):
a = n_t_pert
b = n_species
c = n_f_grid
d = n_p_grid

Full case (with temperature perturbations and vmr perturbations):
a = n_t_pert
b = n_species + n_nonlinear_species * ( n_nls_pert - 1 )
c = n_f_grid
d = n_p_grid

Note that the last three dimensions are identical to the dimensions of abs_per_tg in ARTS-1-0. This should simplify computation of the lookup table with this old ARTS version.

Definition at line 239 of file gas_abs_lookup.h.

Referenced by abs_lookupCreate(), Adapt(), Extract(), xml_read_from_stream(), and xml_write_to_stream().

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


Public Member Functions
	GasAbsLookup ()
void	Adapt (const ArrayOfArrayOfSpeciesTag &current_species, ConstVectorView current_f_grid)
	Adapt lookup table to current calculation.
void	Extract (Matrix &sga, const Index &p_interp_order, const Index &t_interp_order, const Index &h2o_interp_order, const Index &f_index, const Numeric &p, const Numeric &T, ConstVectorView abs_vmrs) const
	Extract scalar gas absorption coefficients from the lookup table.
void	GetFgrid (Vector &f) const
void	GetPgrid (Vector &p) const
Private Attributes
ArrayOfArrayOfSpeciesTag	species
	The species tags for which the table is valid.
ArrayOfIndex	nonlinear_species
	The species tags with non-linear treatment.
Vector	f_grid
	The frequency grid [Hz].
Vector	p_grid
	The pressure grid for the table [Pa].
Vector	log_p_grid
	The natural log of the pressure grid.
Matrix	vmrs_ref
	The reference VMR profiles.
Vector	t_ref
	The reference temperature profile [K].
Vector	t_pert
	The vector of temperature perturbations [K].
Vector	nls_pert
	The vector of perturbations for the VMRs of the nonlinear species.
Tensor4	xsec
	Absorption cross sections.
Friends
void	xml_read_from_stream (istream &is_xml, GasAbsLookup &gal, bifstream *pbifs)
	Reads GasAbsLookup from XML input stream.
void	xml_write_to_stream (ostream &os_xml, const GasAbsLookup &gal, bofstream *pbofs, const String &name)
	Writes GasAbsLookup to XML output stream.
void	abs_lookupCreate (GasAbsLookup &abs_lookup, Index &abs_lookup_is_adapted, const ArrayOfArrayOfSpeciesTag &abs_species, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfArrayOfSpeciesTag &abs_nls, const Vector &f_grid, const Vector &abs_p, const Matrix &abs_vmrs, const Vector &abs_t, const Vector &abs_t_pert, const Vector &abs_nls_pert, const Vector &abs_n2, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters)
	WORKSPACE METHOD: abs_lookupCreate.
Numeric	calc_lookup_error (const GasAbsLookup &al, const Index &abs_p_interp_order, const Index &abs_t_interp_order, const Index &abs_nls_interp_order, const bool ignore_errors, const Vector &abs_n2, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters, const Numeric &local_p, const Numeric &local_t, const Vector &local_vmrs)
	Compare lookup and LBL calculation.
void	abs_lookupTestAccuracy (const GasAbsLookup &abs_lookup, const Index &abs_lookup_is_adapted, const Index &abs_p_interp_order, const Index &abs_t_interp_order, const Index &abs_nls_interp_order, const Vector &abs_n2, const ArrayOfArrayOfLineRecord &abs_lines_per_species, const ArrayOfLineshapeSpec &abs_lineshape, const ArrayOfString &abs_cont_names, const ArrayOfString &abs_cont_models, const ArrayOfVector &abs_cont_parameters)
	WORKSPACE METHOD: abs_lookupTestAccuracy.