<?xml version="1.0" encoding="UTF-8"?>
<!-- =================================================================

                   Dynamic Aerospace Vehicle Exchange DTD            
                        Function Data Representation                   
                                                                
                      Version: 2.0 Release Candidate 4                             
                            6 January 2011                                       
                                                                
    This DTD module is identified by these PUBLIC and SYSTEM       
    identifiers:                                                   
                                                                
    PUBLIC "-//AIAA//DTD for Flight Dynamic Models - Functions 2.0//EN" 
    SYSTEM "http://daveml.org/DTDs/2p0RC4/DAVEfunc.dtd"
                                                                
    Developed by:

      American Institute of Aeronautics and Astronautics (AIAA)
      Modeling & Simulation Technical Committee
      Simulation Modeling Standards Subcommittee

    Contact information:

      E. Bruce Jackson <mailto:bruce.jackson@nasa.gov>
      Bruce L. Hildreth <mailto:bhildreth@jfti.com>                         
      Persistent DAVE-ML contact <mailto:info@daveml.org>
      <http://daveml.org>

    Purpose: 

      Proposed standard for exchanging dynamic models of aerospace
      vehicles, including aero, engine, gear, inertia, and control
      models.
                                                                
      This preliminary version defines static models typically
      associated with aerodynamic subsystem models, but can be used to
      describe any non-linear multi-dimensional function.
                                                                
    Status:                                                         
      In development. Direct comments to above contacts.

  
     ================================================================= -->

<!-- =================================================================


    Acknowledgments:                                                

    The editors would like to acknowledge the contributions,
    encouragement and helpful suggestions from Dennis Linse
    (originally SAIC, now Vuelo Software Analysis), Jon Berndt (Jacobs
    Sverdrup), Brent York (Indra), Bill Cleveland (NASA Ames), Geoff
    Brian (Australia's DSTO), J. Dana McMinn (NASA Langley), Peter
    Grant (UTIAS), Giovanni A. Cignoni (University of Pisa), Daniel
    M. Newman (formerly Ball Aerospace, now Quantitative Aeronautics),
    Hilary Keating (Fortburn Pty. Ltd.), Riley Rainey (SDS
    International), Jeremy Furtek (Delphi Research) and Randy
    Brumbaugh (Indigo Innovations).

  
     ================================================================= -->

<!-- =================================================================

    Include the MathML2 DTD for any math markup
  
     ================================================================= -->

<!ENTITY % mathml2 PUBLIC "-//W3C//DTD MathML 2.0//EN"
        "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
%mathml2;


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 0 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      Root element is DAVEfunc, composed of a file header element
      followed by one or more variable definitions and zero or more
      breakpoint definitions, gridded or ungridded table definitions,
      and function elements.
    
     ================================================================= -->

<!ELEMENT DAVEfunc (
      fileHeader, 
      variableDef+, 
      breakpointDef*, 
      griddedTableDef*, 
      ungriddedTableDef*, 
      function*, 
      checkData?
    )
>
<!ATTLIST DAVEfunc
     xmlns	CDATA	#FIXED	'http://daveml.org/2010/DAVEML'
>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 1 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      The header element requires at least one author and a creation date;
      optional content includes version indicator, description,
      references, and modification records.
    
     ================================================================= -->

<!ELEMENT fileHeader (
      author+, 
      (creationDate | fileCreationDate), 
      fileVersion?, 
      description?, 
      reference*, 
      modificationRecord*, 
      provenance*
    )
>
<!ATTLIST fileHeader
     name	CDATA	#IMPLIED
>

<!-- =================================================================

      variableDef elements provide wiring information (i.e., they
      identify the input and output signals used by these function
      blocks). They also provide MathML content markup to indicate any
      calculation required to arrive at the value of the variable,
      using other variables as inputs.  The variable definition can
      include statistical information regarding the uncertainty of the
      values which it might take on, when measured after any
      calculation is performed. Information about the reason for
      inclusion or change to this element can be included in an
      optional provenance sub-element.

      If either or both min or max attributes are specified, the
      implementer must limit the final value of the variable to remain
      within the specified bound(s). These attributes imply a one- or
      two-sided limiter function downstream of any specified
      calculation, input signal, or initial value.

      Min and max attributes may only be fixed numeric values. To
      provide variable limits, the modeler should employ the piecewise
      MathML element in a calculation subelement.
    
    
     ================================================================= -->

<!ELEMENT variableDef (
      description?, 
      (provenance | provenanceRef)?, 
      calculation?, 
      (isInput | isControl | isDisturbance)?, 
      isState?, 
      isStateDeriv?, 
      isOutput?, 
      isStdAIAA?, 
      uncertainty?
    )
>
<!ATTLIST variableDef
     name	CDATA	#REQUIRED
     varID	ID	#REQUIRED
     units	CDATA	#REQUIRED
     axisSystem	CDATA	#IMPLIED
     sign	CDATA	#IMPLIED
     alias	CDATA	#IMPLIED
     symbol	CDATA	#IMPLIED
     initialValue	CDATA	#IMPLIED
     minValue	CDATA	#IMPLIED
     maxValue	CDATA	#IMPLIED
>

<!ELEMENT variableRef EMPTY>
<!ATTLIST variableRef
     varID	IDREF	#REQUIRED
>

<!-- =================================================================

      A breakpointDef lists gridded table breakpoints.
      Since these are separate from function data they may be reused.
    
     ================================================================= -->

<!ELEMENT breakpointDef (
      description?, 
      bpVals
    )
>
<!ATTLIST breakpointDef
     name	CDATA	#IMPLIED
     bpID	ID	#REQUIRED
     units	CDATA	#IMPLIED
>

<!-- =================================================================

      bpVals is a set of breakpoints (i.e., a set of independent
      variable values associated with one dimension of a gridded table
      of data). An example would be the Mach or angle-of-attack values
      that define the coordinates of each data point in a
      2D coefficient value table.
    
     ================================================================= -->

<!ELEMENT bpVals (#PCDATA)>


<!-- =================================================================

      A griddedTableDef contains points arranged in an orthogonal (but
      multi-dimensional) array, where the independent variables are
      defined by separate breakpoint vectors.  This table definition
      may be specified separately from the actual function
      declaration.
    
     ================================================================= -->

<!ELEMENT griddedTableDef (
      description?, 
      (provenance | provenanceRef)?, 
      breakpointRefs, 
      uncertainty?, 
      dataTable
    )
>
<!ATTLIST griddedTableDef
     name	CDATA	#IMPLIED
     gtID	ID	#REQUIRED
     units	CDATA	#IMPLIED
>

<!-- =================================================================

      An ungriddedTableDef contains points that are not in an
      orthogonal grid pattern; thus, the independent variable
      coordinates are specified for each dependent variable value.
      This table definition may be specified separately from the
      actual function declaration.
    
     ================================================================= -->

<!ELEMENT ungriddedTableDef (
      description?, 
      (provenance | provenanceRef)?, 
      uncertainty?, 
      dataPoint+
    )
>
<!ATTLIST ungriddedTableDef
     name	CDATA	#IMPLIED
     utID	ID	#REQUIRED
     units	CDATA	#IMPLIED
>

<!-- =================================================================

      Each function has optional description, optional provenance, and
      either a simple input/output table values or references to more
      complete (possible multiple) input, output, and function data
      elements.
    
     ================================================================= -->

<!ELEMENT function (
      description?, 
      (provenance | provenanceRef)?, 
      ((
        independentVarPts+, 
        dependentVarPts
      ) | (
        independentVarRef+, 
        dependentVarRef, 
        functionDefn
      ))
    )
>
<!ATTLIST function
     name	CDATA	#REQUIRED
>

<!-- =================================================================

      This top-level element is the place-holder for verification data
      of various forms for the encoded model. It will include static
      check cases, trim shots, and dynamic check case information.
      The provenance sub-element is now deprecated and has been moved
      to individual staticShots; it is allowed here for backwards
      compatibility. 
    
     ================================================================= -->

<!ELEMENT checkData (
      (provenance | provenanceRef)?, 
      staticShot+
    )
>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 2 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      author includes alternate means of identifying author using XNS
      or normal e-mail/address. The address sub-element is to be
      replaced with the more complete contactInfo sub-element.
    
     ================================================================= -->

<!ELEMENT author (address* | contactInfo*)>
<!ATTLIST author
     name	CDATA	#REQUIRED
     org	CDATA	#REQUIRED
     xns	CDATA	#IMPLIED
     email	CDATA	#IMPLIED
>

<!-- =================================================================

      creationDate is simply a string with a date in it.  We
      follow ISO 8601 and use dates like "2004-01-02" to refer to
      January 2, 2004. 
    
     ================================================================= -->

<!ELEMENT creationDate EMPTY>
<!ATTLIST creationDate
     date	CDATA	#REQUIRED
>

<!-- =================================================================

      fileCreationDate is simply a string with a date in it.  We
      follow ISO 8601 and use dates like "2004-01-02" to refer to
      January 2, 2004. Its use is now deprecated in favor of the
      simpler creationDate.
    
     ================================================================= -->

<!ELEMENT fileCreationDate EMPTY>
<!ATTLIST fileCreationDate
     date	CDATA	#REQUIRED
>

<!-- =================================================================

      This is a string describing, in some arbitrary text, the version
      identifier for this function description.
    
     ================================================================= -->

<!ELEMENT fileVersion (#PCDATA)>


<!-- =================================================================

      The description element is a textual description of an
      entity. The full UNICODE character set is supported by XML but
      may not be available in all processing applications.
    
     ================================================================= -->

<!ELEMENT description (#PCDATA)>


<!-- =================================================================

      The presence of the isOutput element indicates that this
      variable should be forced to be an output, even if it is used
      internally as an input elsewhere. Otherwise, the processing
      program may assume a signal defined with a calculation and used
      subsequently in the model is only an internal signal.
    
     ================================================================= -->

<!ELEMENT isOutput EMPTY>


<!-- =================================================================

      The presence of an isState element indicates that this variable
      is one of possibly multiple state variables in a dynamic model;
      this tells the processing entity that this is the output of an
      integrator (for continuous models) or a discretely updated state
      (for discrete models).
    
     ================================================================= -->

<!ELEMENT isState EMPTY>


<!-- =================================================================

      The presence of an isStateDeriv element indicates that this
      variable is one of possibly several state derivative variables
      in a dynamic model; this tells the processing entity that this
      is the output of an integrator (for continuous models only).
    
     ================================================================= -->

<!ELEMENT isStateDeriv EMPTY>


<!-- =================================================================

      The presence of an isInput element indicates that this variable
      is an input signal to the model.
    
     ================================================================= -->

<!ELEMENT isInput EMPTY>


<!-- =================================================================

      The presence of an isControl element indicates that this signal
      is a simulation control parameter used to vary the operation of
      the model, e.g. the time step size. Such parameters should be
      ignored when performing linear model extraction (for example)
      and should not significantly modify the dynamic behavior of the
      model.
    
     ================================================================= -->

<!ELEMENT isControl EMPTY>


<!-- =================================================================

      The presence of an isDisturbance element indicates that this
      signal is an external disturbance input to the model and can be
      ignored when performing linear model extraction (for
      example). Such parameters should not significantly modify the
      nominal dynamic behavior of the model.
    
     ================================================================= -->

<!ELEMENT isDisturbance EMPTY>


<!-- =================================================================

      The presence of an isStdAIAA element indicates that this
      variable is one of the standard AIAA variable names
      which should be recognizable exterior to this module
      (e.g. AngleOfAttack_deg). This flag should assist importing tools in
      determining when an input or output should match a
      facility-provided signal name without requiring further
      information.
    
     ================================================================= -->

<!ELEMENT isStdAIAA EMPTY>


<!-- =================================================================

      The calculation element wraps around MathML 2 content markup
      describing how the signal is calculated. The calculation may
      include both constants and variables; other variables are
      included by using their varID string in a MathML content
      identifier (ci) element. The calculation element must have one
      and only one subelement, and the subelement must be a 'math'
      element containing 'content' markup.
    
     ================================================================= -->

<!ELEMENT calculation (math)>


<!-- =================================================================

      This element gives identifying (citation) information to an
      external, possibly on-line, reference document, including a
      user-specified author, title, classification, accession number,
      date and URL.
    
     ================================================================= -->

<!ELEMENT reference (description?)>
<!ATTLIST reference
     xmlns:xlink	CDATA	#FIXED	'http://www.w3.org/1999/xlink'
     xlink:type	(simple)	#FIXED	'simple'
     refID	ID	#REQUIRED
     author	CDATA	#REQUIRED
     title	CDATA	#REQUIRED
     classification	CDATA	#IMPLIED
     accession	CDATA	#IMPLIED
     date	CDATA	#REQUIRED
     xlink:href	CDATA	#IMPLIED
>

<!-- =================================================================

      A modificationRecord associates a single letter (such as
      modification "A") with modification author(s), address, and any
      optional external reference documents, in keeping with the AIAA
      draft standard.
    
     ================================================================= -->

<!ELEMENT modificationRecord (
      author+, 
      description?, 
      extraDocRef*
    )
>
<!ATTLIST modificationRecord
     modID	ID	#REQUIRED
     date	CDATA	#REQUIRED
     refID	IDREF	#IMPLIED
>

<!-- =================================================================

      A single modification event may have more than one documented
      reference. This element can be used in place of the refID
      attribute in a modificationRecord to record more than one
      refIDs, pointing to the referenced document.
    
     ================================================================= -->

<!ELEMENT extraDocRef EMPTY>
<!ATTLIST extraDocRef
     refID	IDREF	#REQUIRED
>

<!-- =================================================================

      The provenance element describes the history or source of the
      model data and includes author, date, and zero or more
      references to documents and modification records.
    
     ================================================================= -->

<!ELEMENT provenance (
      author+, 
      (creationDate | functionCreationDate), 
      documentRef*, 
      modificationRef*, 
      description?
    )
>
<!ATTLIST provenance
     provID	ID	#IMPLIED
>

<!-- =================================================================
 
      When the provenance of a set of several data is identical, the
      first provenance element should be given a provID and referenced by
      later provenanceRef elements.
    
     ================================================================= -->

<!ELEMENT provenanceRef EMPTY>
<!ATTLIST provenanceRef
     provID	IDREF	#REQUIRED
>

<!-- =================================================================

      An independentVarPts element is a simple white space- or
      comma-separated list of breakpoints and contains a mandatory
      varID identifier as well as optional name, units, and sign
      convention attributes.

      An optional extrapolate attribute describes how to extrapolate
      the output value when the input value exceeds specified values
      (default is 'neither,' meaning the value of the table is held
      constant at the nearest defined value). An optional interpolate
      attribute indicates how to perform the interpolation within the
      table (supporting discrete, linear, cubic or quadratic
      splines). There are three different discrete options: 'discrete'
      means nearest-neighbor, with an exact mid-point value being
      rounded in the positive direction; 'ceiling' means the function
      takes on the value associated with the next (numerically) higher
      independent breakpoint as soon as the original value is exceeded;
      and 'floor' means the function holds the value associated with
      each breakpoint until the next (numerically) higher breakpoint
      value is reached by the independent argument. The default
      interpolation attribute value is 'linear.'

      This element is used for simple functions that do not share
      breakpoint or table values with other functions.
    
     ================================================================= -->

<!ELEMENT independentVarPts (#PCDATA)>
<!ATTLIST independentVarPts
     varID	IDREF	#REQUIRED
     name	CDATA	#IMPLIED
     units	CDATA	#IMPLIED
     sign	CDATA	#IMPLIED
     extrapolate	(neither | min | max | both) #IMPLIED
     interpolate	(discrete | floor | ceiling | linear | quadraticSpline | cubicSpline) #IMPLIED
>

<!-- =================================================================

      A dependentVarPts element is a simple comma- or
      white space-delimited list of function values and contains a
      mandatory varID as well as optional name, units, and sign
      convention attributes. Data points are arranged as single
      vector with last-specified breakpoint values changing most
      frequently. Note that the number of dependent values must equal
      the product of the number of independent values for this simple,
      gridded, realization. This element is used for simple functions
      that do not share breakpoint or table values with other
      functions.
    
     ================================================================= -->

<!ELEMENT dependentVarPts (#PCDATA)>
<!ATTLIST dependentVarPts
     varID	IDREF	#REQUIRED
     name	CDATA	#IMPLIED
     units	CDATA	#IMPLIED
     sign	CDATA	#IMPLIED
>

<!-- =================================================================

      An independentVarRef more fully describes the input mapping of
      the function by pointing to a separate breakpoint definition
      element.

      An optional extrapolate attribute describes how to extrapolate
      the output value when the input value exceeds specified values
      (default is 'neither,' meaning the value of the table is held
      constant at the nearest defined value). An optional interpolate
      attribute indicates how to perform the interpolation within the
      table (supporting discrete, linear, cubic or quadratic
      splines). There are three different discrete options: 'discrete'
      means nearest-neighbor, with an exact mid-point value being
      rounded in the positive direction; 'floor' means the function
      takes on the value associated with the next (numerically) higher
      independent breakpoint as soon as original value is exceeded;
      and 'ceiling' means the function holds the value associated with
      each breakpoint until the next (numerically) higher breakpoint
      value is reached by the independent argument. The default
      interpolation attribute value is 'linear.'

      Note also that the option min and max attributes serve to limit
      the numeric range of the independent (function input) variable;
      these attributes are independent of and serve as additional
      range contraints with respect to any minValue or maxValue
      attribute associated with the independent variable itself.

      This element allows reuse of common breakpoint values for many
      tables but with possible differences in interpolation or
      extrapolation for each use.
    
     ================================================================= -->

<!ELEMENT independentVarRef EMPTY>
<!ATTLIST independentVarRef
     varID	IDREF	#REQUIRED
     min	CDATA	#IMPLIED
     max	CDATA	#IMPLIED
     extrapolate	(neither | min | max | both) #IMPLIED
     interpolate	(discrete | floor | ceiling | linear | quadraticSpline | cubicSpline) #IMPLIED
>

<!-- =================================================================

      A dependentVarRef ties the output of a function to a signal name
      defined previously in a variable definition.
    
     ================================================================= -->

<!ELEMENT dependentVarRef EMPTY>
<!ATTLIST dependentVarRef
     varID	IDREF	#REQUIRED
>

<!-- =================================================================

      A functionDefn defines how function is represented in one of two
      possible ways: gridded (implies breakpoints) or ungridded (with
      explicit independent values for each point).
    
     ================================================================= -->

<!ELEMENT functionDefn (griddedTableRef | griddedTableDef | griddedTable | ungriddedTableRef | ungriddedTableDef | ungriddedTable)>
<!ATTLIST functionDefn
     name	CDATA	#IMPLIED
>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 3 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!ELEMENT address (#PCDATA)>


<!-- =================================================================

      Used to provide contact information about an author. Use
      contactInfoType to differentiate what information is being
      conveyed and contactLocation to denote location of the address.
    
     ================================================================= -->

<!ELEMENT contactInfo (#PCDATA)>
<!ATTLIST contactInfo
     contactInfoType	(address | phone | fax | email | iname | web) #IMPLIED
     contactLocation	(professional | personal | mobile) #IMPLIED
>

<!-- =================================================================

      functionCreationDate is simply a string with a date in it.  We
      follow ISO 8601 and use dates like "2004-01-02" to refer to
      January 2, 2004. Its use is now deprecated in favor of the 
      simpler creationDate.
    
     ================================================================= -->

<!ELEMENT functionCreationDate EMPTY>
<!ATTLIST functionCreationDate
     date	CDATA	#REQUIRED
>

<!ELEMENT documentRef EMPTY>
<!ATTLIST documentRef
     docID	IDREF	#IMPLIED
     refID	IDREF	#REQUIRED
>

<!ELEMENT modificationRef EMPTY>
<!ATTLIST modificationRef
     modID	IDREF	#REQUIRED
>

<!ELEMENT griddedTableRef EMPTY>
<!ATTLIST griddedTableRef
     gtID	IDREF	#REQUIRED
>

<!ELEMENT griddedTable (
      breakpointRefs, 
      confidenceBound?, 
      dataTable
    )
>
<!ATTLIST griddedTable
     name	CDATA	#IMPLIED
>

<!ELEMENT ungriddedTableRef EMPTY>
<!ATTLIST ungriddedTableRef
     utID	IDREF	#REQUIRED
>

<!ELEMENT ungriddedTable (
      confidenceBound?, 
      dataPoint+
    )
>
<!ATTLIST ungriddedTable
     name	CDATA	#IMPLIED
>

<!-- =================================================================

      Contains a description of the inputs and outputs, and possibly internal values, of a DAVE-ML
      model in a particular instant of time.
    
     ================================================================= -->

<!ELEMENT staticShot (
      description?, 
      (provenance | provenanceRef)?, 
      checkInputs?, 
      internalValues?, 
      checkOutputs
    )
>
<!ATTLIST staticShot
     name	CDATA	#REQUIRED
     refID	IDREF	#IMPLIED
>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 4 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      The breakpointRefs elements tie the independent variable names
      for the function to specific breakpoint values defined earlier.
    
     ================================================================= -->

<!ELEMENT breakpointRefs (bpRef+)>


<!-- =================================================================

      The confidenceBound element is used to declare the confidence
      interval associated with the data table. This is a place-holder
      and will be removed in a future version of DAVE-ML.
    
     ================================================================= -->

<!ELEMENT confidenceBound EMPTY>
<!ATTLIST confidenceBound
     value	CDATA	#REQUIRED
>

<!-- =================================================================

      The uncertainty element is used in function and parameter
      definitions to describe statistical variance in the possible
      value of that function or parameter value. Only Gaussian
      (normal) or uniform distributions of continuous random variable
      distribution functions are supported.
    
     ================================================================= -->

<!ELEMENT uncertainty (normalPDF | uniformPDF)>
<!ATTLIST uncertainty
     effect	(additive | multiplicative | percentage | absolute) #REQUIRED
>

<!-- =================================================================

      The dataTable element is used by gridded tables where the indep.
      variable values are implied by breakpoint sets. Thus, the data
      embedded between the dataTable element tags is expected to be
      sorted ASCII values of the gridded table, wherein the last
      independent variable listed in the function header varies most
      rapidly.

      The table data point values are specified as comma- or
      white space-separated values in conventional floating-point
      notation (0.93638E-06) in a single long sequence as if the table
      had been unraveled with the last-specified dimension changing
      most rapidly.  Line breaks are to be ignored. Comments may be
      embedded in the table to promote [human] readability, with
      appropriate escaping characters.

      A dataTable element can also be used in an uncertainty element
      to provide duplicate uncertainty bound values.

    
     ================================================================= -->

<!ELEMENT dataTable (#PCDATA)>


<!-- =================================================================

      The dataPoint element is used by ungridded tables to list the
      values of independent variables that are associated with each
      value of dependent variable. For example:
                                                                 
 <dataPoint>                                                     
   0.1, -4.0, 0.2      <!- Mach, alpha, CL ->                    
 </dataPoint>                                                    
 <dataPoint>                                                     
   0.1,  0.0, 0.6      <!- Mach, alpha  CL ->                    
 </dataPoint>                                                    
                                                                 
      Each data point may have associated with it a modification tag
      to document the genesis of that particular point.  No
      requirement on ordering of independent variables is implied.
      Since this is an ungridded table, the interpreting application is
      required to handle what may be unsorted data.
    
     ================================================================= -->

<!ELEMENT dataPoint (#PCDATA)>
<!ATTLIST dataPoint
     modID	IDREF	#IMPLIED
>

<!-- =================================================================
Specifies the contents of the input vector for the given check case.
     ================================================================= -->

<!ELEMENT checkInputs (signal+)>


<!-- =================================================================

      Provides a set of all internal variable values to assist in debugging recalcitrant
      implementations of DAVE-ML import tools.
    
     ================================================================= -->

<!ELEMENT internalValues (signal+)>


<!-- =================================================================

      Specifies the contents of the output vector for the given check
      case.
    
     ================================================================= -->

<!ELEMENT checkOutputs (signal+)>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 5 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      The bpRef element provides references to a previously-defined
      breakpoint set so breakpoints can be defined separately from,
      and reused by, several data tables.
    
     ================================================================= -->

<!ELEMENT bpRef EMPTY>
<!ATTLIST bpRef
     bpID	IDREF	#REQUIRED
>

<!-- =================================================================

      In a normally distributed random variable, a symmetrical
      distribution of given standard deviation is assumed about the
      nominal value (which is given elsewhere in the parent element).

      The correlatesWith sub-element references other functions or
      variables that have a linear correlation to the current
      parameter or function. The correlation sub-element specifies the
      correlation coefficient and references the other function or
      variable whose random value helps determine the value of this
      parameter.
    
     ================================================================= -->

<!ELEMENT normalPDF (
      bounds, 
      correlatesWith*, 
      correlation*
    )
>
<!ATTLIST normalPDF
     numSigmas	CDATA	#REQUIRED
>

<!-- =================================================================

      In a uniformly distributed random variable, the value of the
      parameter has equal likelihood of assuming any value within the
      (possibly asymmetric, implied by specifying two) bounds, which
      must bracket the nominal value (which is given elsewhere in the
      parent element).
    
     ================================================================= -->

<!ELEMENT uniformPDF (bounds+)>


<!-- =================================================================

      This element contains some description of the statistical limits
      to the values the citing parameter element might take on. This
      can be in the form of a scalar value, a private dataTable, or a
      variableRef. In the more common instance, this element will
      either be a scalar constant value or a simple table whose
      dimensions must match the parent nominal function table and
      whose independent variables are identical to the nominal
      table. It is also possible that this limit be determined by an
      independent variable, either previously defined or defined
      in-line with this element. It does not make sense to have a
      dataTable cited if this bounds element is associated with
      anything other than an identically shaped function table.
    
     ================================================================= -->

<!ELEMENT bounds (#PCDATA | dataTable | variableDef | variableRef)*>


<!-- =================================================================

      When present, this element indicates the parent function or
      variable is correlated with the referenced other function or
      variable in a linear sense.  This alerts the application that
      the random number used to calculate this function's or variable's
      immediate value will be used to calculate another function's or
      variable's value.
    
     ================================================================= -->

<!ELEMENT correlatesWith EMPTY>
<!ATTLIST correlatesWith
     varID	IDREF	#REQUIRED
>

<!-- =================================================================

      When present, this element indicates the parent function or
      variable is correlated with the referenced other function or
      variable in a linear sense and gives the correlation
      coefficient for determining this function's random value based
      upon the correlating function(s)'s random value.
    
     ================================================================= -->

<!ELEMENT correlation EMPTY>
<!ATTLIST correlation
     varID	IDREF	#REQUIRED
     corrCoef	CDATA	#REQUIRED
>

<!-- =================================================================

      This element is used to document the name, ID, value, tolerance,
      and units of measure for check-cases. When used with checkInputs
      or checkOutputs, the signalName sub-element must be present
      (since check cases are viewed from "outside" the model); when
      used in an internalValues element, the varID sub-element should
      be used to identify the signal by its model-unique internal
      reference. When used in a checkOutputs vector, the tol element
      must be present. Tolerance is specified as a maximum absolute
      difference between the expected and actual value.

      The signalID sub-element is now deprecated in favor of the more
      consistent varID.
    
     ================================================================= -->

<!ELEMENT signal (
      ((
        signalName, 
        signalUnits
      ) | (
        (varID | signalID)
      )), 
      signalValue, 
      tol?
    )
>


<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<!--                         Level 6 Elements                         -->
<!-- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->

<!-- =================================================================

      Used inside a checkCase element to specify the input or output
      variable name
    
     ================================================================= -->

<!ELEMENT signalName (#PCDATA)>


<!-- =================================================================

      Used to specify the input or output varID. Now deprecated; reuse
      of varID is best practice.
    
     ================================================================= -->

<!ELEMENT signalID (#PCDATA)>


<!-- =================================================================

      Used to specify the input or output varID. Replaces earlier
      signalID element.
    
     ================================================================= -->

<!ELEMENT varID (#PCDATA)>


<!-- =================================================================

      Used inside a checkCase element to specify the units-of-measure
      for an input or output variable, for verification of proper
      implementation of a model.
    
     ================================================================= -->

<!ELEMENT signalUnits (#PCDATA)>


<!-- =================================================================

      Used to give the current value of an internal signal or
      input/output variable, for verification of proper implementation
      of a model.
    
     ================================================================= -->

<!ELEMENT signalValue (#PCDATA)>


<!-- =================================================================

      This element specifies the allowable tolerance of error in an
      output value such that the model can be considered verified. It
      is assumed all uncertainty is removed in performing the model
      calculations. Tolerance is specified as a maximum absolute
      difference between the expected and actual value.
    
     ================================================================= -->

<!ELEMENT tol (#PCDATA)>