HESSI Objects Reference Manual

Contents

 

Class diagram

Class summary

Classes that are usually accessed by users are written in boldface. Other classes are internal steps used by collaborating classes.

Parameter summary

Each control parameter name is associated with a keyword that allows to set its value using the procedure Set. Similarly, each name of an infor parameter is associated with a keyword that allows to get its value using the function Get(). Control parameters can be set with any method. Once a control parameter is set, its value is kept in the object’s internal memory, i.e. calls to Set are needed only when the value of a parameter changes.

There are two types of parameters: control parameters and information parameters.Control parameters inluence the way individual classes process data. Information parameters provide (output) values associated with the processing of the data. The default value of a keyword is the value used in the object when the keyword is not used.

Method summary

A procedure method is called by obj->proc_name where proc_name is the name of the method. A function method is called by result = obj->func_name whereby result is any IDL variable name and func_name is the name of the method. Methods and functions accept any keyword parameters of type “Set” as defined in the section Keywords below.

 

Keyword summary

Keywords can be used either to request a specific subset of the data associated with a specific object, or to do a specific, non-standard processing. Keywords to select data subsets start in general with the prefix THIS_ and are used only with the method GetData().

Data structure summary

 

Object classes: detail

Framework

Generic basis class used to support scientific data analysis tasks. The framework contains four main elements:

1.      The primary data which needs to be managed;

2.      The control parameters;

3.      The informational parameters;

4.      The administration parameters.

The framework is inherited by application-specific concrete classes. It is based on the template method design pattern. The abstract class cannot be used without a concrete class. Look for the document “HESSI Object-Oriented Design Concept” for more information on frameworks.

Construction

Only by inheritance in concrete classes.

Methods defined in this class

-       Get() : Retrieves ancillary parameters, from control, information, administration and/or source objects. If only one parameter is requested, Get returns the value of this parameter unless /NOSINGLE is set. If more than one parameter are requested, Get returns an anonymous structure that have one tag for each parameter requested. For pointer-type variables, Get does an automatic dereferencing, i.e. it returns the variables to which the pointers are pointing instead of the pointers (but see also /NO_DEREFERENCE).

-       GetData() : Retrieves primary data. When this function is called, the object checks whether the control parameters have changed, using the function Need_Update (see below). If parameters have changed, it assumes that data need to be recomputed and Process is called. Otherwise the object retrieves the contents of its memory, and makes the appropriate selection depending on the keyword parameters. Note that most of the time this procedure is only the generic part of a redefined procedure GetData in the concrete class.

-       Need_Update() : Returns “1” if the object must call the procedure Process to update its state; otherwise “0.”

-       Plot : Plots data associated with an object. This generally first calls GetData, and generates a “view” of the data. Often, tough, the data may be strongly summarized. The generic plotting routine is empty.

-       Process : This procedure is called whenever an object needs to be updated. It reads in the control parameters associated with the class, reads in the data form a source object (or from any other sources), process the source data and stpres the results into the object’s memory.

-       Print : Prints control, information, and administration parameters.

-       Set : Sets values to control parameters. Set does not just store the parameter values into a data structure. It first checks if the parameters are the same as those already stored. If they are, it just returns. If they are not, it will set the need_update flag in the administration structure to 1.

-       SetData : Input primary data into the framework. This is usually called by the procedure Process

-       Write : Write FITS files, usually binary extensions, with the data associated with the object.

Parameters defined in this class

-       VERBOSE (Get, Set) Flag for controlling whether messages commenting the process are printed or not. Defined in: {hsi_admin_control}, class Structure_Manager.  Format: byte scalar, Range: 0B or 1B.  Default: 0B.  Example:

o->Set, /VERBOSE, /THIS_CLASS_ONLY

sets the verbose flag for the clas o only, i.e. the source classes of o will not be influenced by this setting.

Keywords defined in this class

-       /ADMIN_ONLY: [Get()] Set this to retrieve only the administration  parameters (verbose,

-       ADMIN_STRUCT:(Set) Initializes the admininstration structure type {admin_struct}

-       CLASS_NAME: (Get, GetData) If set to a valid class name (string), retrieves parameters for the class specified and all its sources recursively. Default: current class

-       /CONTROL_ONLY: [Get()]  Set this to retrieve only control parameters

-       CONTROL_STRUCT (Set): Sets the controil structure

-       FOUND [Get()] : Set this to a named variable to get the names of  the parameters found in a string array

-       /INFO_ONLY: [Get()]  Set this to retrieve only information parameters

-       POINTER (GetData): If set, retrievs a reference to the (orginal) data insteade of a copy.

-       SOURCE_ONLY: [Get()]  Set this to retrieve the source object reference. See also SRC_INDEX.

-       SRC_INDEX: [Get()]  Set this to the index or array of indices   of the source object(s) you want  to get with SOURCE_ONLY. Default: 0

-       THIS_CLASS_ONLY: [Get()]  Set this to retrieve data only for the   current class or for the class specified   by CLASS_NAME

-       OBJECT_REFERENCE: [Get()]  Set this to retrieves the object  reference of the class specified by    CLASS_NAME

-       NO_DEREFERENCE: [Get()]  Set this to prefent automatic dereferencing of pointer-type tags.

-       NOSINGLE: [Get()]  Set this to retrieve an anonymous structure even for a single parameter request

-       NOT_FOUND (Set): Returns an array of strings containingthe name of the keywords that have not been found

-       XAXIS [GetData()] Returns the x axis of the data in the class. It is equivalent to a call to the function GetAxisThis may be the pixel location (in arcseconds) if the class is HSI_Image, or time if the class is HSI_Binned_Eventlist Use with the method: GetData, classes HSI_Binned_Eventlist HSI_Image HSI_Lightcurve HSI_Spectrogram. Example:  image_x_axis = o->GetData( /XAXIS )

-       YAXIS [GetData()] Returns the y axis of the data in the class. This may be the pixel location (in arcseconds) if the class is HSI_Image, or the energy edges for the class HSI_Lightcurve.  Example:  image_x_axis = o->GetData( /XAXIS )

HSI_Aspect_Solution

Parameters defined in this class

SASZERO (Get, Set)

Specifies that the Aspect solution sould be considered as perfect.

Defined in:HSI_Calib_Eventlist

Format: Byte scalar with either 1 or 0

Range: Either 1 or 0

Default: 0

Example: 

o->Set, /SASZERO

 

HSI_Bproj

Provides access to back projection maps. The back projection class extends the class strategy_holder_passive. The back projection can be calculated using either of the annsec or the visibility modulation pattern. The startegy holder is passive because it just selects its strategy by listening to the modulation pattern object, which really decides which strategy (commanded by imaging_method) to use.

 

HSI_Bproj is just a container. The real work is done by the startegies, either hsi_bproj_annsec or hsi_ bproj_vismod, which are two classes extending the basic class hsi_bproj_strategy.

 

Construction

o = HSI_BProj()

Control parameters defined in this class

None in that class. But look at hsi_bproj_strategy

Information parameters defined in this class

Defined in {hsi_bproj_info}:

     

-       bproj_alg_available: lists the back projection algorithms (i.e, objects) available.Currently, the values are: HSI_VISMOD_BPROJ for visibility back-projection, or HSI_ANNSEC_BPROJ for annular sector back projection.

 

Source class

HSI_Modul_Pattern

Known destination (client) classes

HSI_Modpat_Products, HSI_Image

 

HSI_Bproj_Strategy

Computes the backprojection for a given count rate. The count rate is given either using the parameter vrate, or if vrate is empty (null pointer), the count rate used is the observed count rate.

Construction

O = hsi_bproj()

Primary data type

An image in the form of a 2D array. The dimensions and units of the image are given by image_dim pixel_size

Processing method

The algorithm is defined in the procedure hsi_annsec_bproj

Control parameters

Control parameters for the back projection are defined in the structure hsi_bproj_control.

flatfield (Get, Set)

vrate (Get, Set)

Allows passing an arbitrary count rate to the backprojection object. It must have the dimensions defined by time_bin_min and time_bin_def in hsi_binned_eventlist. The best way to know these dimensions is to look at the observed count rates (see example below)

Defined in: {hsi_bproj_control}, class HSI_BProj

Format:Array of pointers to array of floats. See the examples on how to know th dimension of the array of floats

Range:n/a

Default:array of nil pointers. In this case, the backprojection is computed using the observed count rates.

Example: To set correctly vrate:

will get the observed count rate, assign the values to a new variable whare you can modify them to whatever you want.

Information parameters

There are no information parameters for this class

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HSI_Calib_EventList

Provides data structures and methods to build and access the calibrated event list.

Construction

Methods defined in this class

Control parameters defined in this class

time_bin_def (Get, Set)

Specifies the time bin definition factor for each detector. It is multiplied by TIME_BIN_MIN.

-       Defined in: HSI_Binned_Eventlist

-       Format: 9-Element float array FltArr(9)

-       Range: 1 to ... . You should be very careful when using other values than powers of two

-       Default: [...]

-       Example:

time_bin_min (Get, Set)

Specifies the minimum time bin in binary microseconds. It is multiplied by TIME_BIN_DEF.

·        Defined in: {hsi_binned_evenlist_control}, class HSI_Binned_Eventlist

·        Format: 2-Element integer array IntArr(2)

·        Range: [16,16] to [1024,1024]. Large images may take exessively long to process.

·        Default [64,64]

·        Example:

xyoffset(Get, Set)

Specifies the offset of the map center from the sun center in arcsecs.

·        Defined in: {hsi_calib_eventlist_control}, class HSI_Calib_Eventlist

·        Format: 2-Element float array FltArr(2)

·        Range: [0,0] to [1000,1000].

·        Default: [600,200] for the standard default simulation. No defaults for flare data. The values to set here may be taken from the flare list.

 

Data structures

HSI_Clean

Provides a wrapper for the clean image algorithm.

Construction

Primary data type

An image in the form of a 2D array.

Processing method

The algorithm is defined in the procedure hsi_map_clean

Control parameters

Control parameters for the clean algorithm are defined in the structure hsi_clean_parameters.

Informational parameters

chi_sq
residual

Acessor methods

No accessor methods are implemented in this class.

Display methods

No display methods are implemented in this class. Need_Update

HSI_EventList

Provides data structures and methods to build and access an event list.

Construction

obj = hsi_eventlist()

Methods defined or rewritten in this class

result = obj->Get()

result = obj->GetData( /SCORE THIS_A2D_INDEX=BytArr(27) THIS_ENERGY_BAND=DblArr(2) THIS_TIME_RANGE=DblArr(2)

obj->Plot, THIS_A2D_INDEX=BytArr(27) THIS_ENERGY_BAND=DblArr(2) THIS_TIME_RANGE=DblArr(2)

obj->Write, THIS_A2D_INDEX=BytArr(27) THIS_ENERGY_BAND=DblArr(2) THIS_TIME_RANGE=DblArr(2)

Inherited from Framework: CLEANUP, Get, Set, SetData

Control parameters

Parameters are defined in a single control structure called hsi_eventlist_control.

a2d_index_mask: Allows selecting which a2ds to use. Note that this setting is very low level. Usually you may want to select the detectors instead, with det_index_mask Format: Bytarr( 27 ). Each position of the array correspond to a selected a2d

Range: Each element of the array may take the value 0 or 1.

Default values: BytArr(27) + 1B

Example:

This selects the a2ds 3 to 6.

 

-        

-       energy_band

-       time_range

-       time_unit

-       ut_ref

Informational parameters

Data structures

HSI_Image

Provides data structures and methods for HESSI imaging tasks.

Construction:

O = hsi_image()

Methods defined or overriden in this class

Get( )

result = obj->GetData( XAXIS=xaxis, YAXIS=yaxis )

obj->Plot

Control parameters defined in this class:

image_algorithm

Specifies which algorithm is used to reconstruct the image. 

Format:String scalar

Default:’bproj’

Example:

Data structures defined in this class:

HSI_Image_Alg

HESSI IMAGING ALGORITHM ABSTRACT CLASS DEFINITION. This abstract class defines operations common to all imaging algorithms used for HESSI image processing. It leaves up to the subclasses the behavior that can vary. It is inherited by a concrete class that usually has the same name as the algorithm it implements. This class is a realization of the Template Method design pattern.

Construction:

Only through the concrete classes

Methods defined or overriden in this class

The procedure Process loads the control parameters and passes the control to the child class with image_alg_hook. Once it returns from image_alg_hook, it stores the information parameters that may come out of the concrete class into the object. Image_alg_hook must be defined in the concrete class.

Control parameters defined in this class: