[NeXus-tech] [Fwd: Re: dimensions]

[Pete Jemian]

perhaps:
---------------------------------% clip here 
%---------------------------------
    <field name="final_wavelength" type="NX_FLOAT" units="NX_LENGTH">
        <doc>Wavelength on leaving beamline component</doc>
        <dimensions size="1">
            <dim index="1">:</dim>
        </dimensions>
    </field>
    <field name="final_beam_divergence" type="NX_FLOAT" units="NX_ANGLE">
        <doc>Divergence FWHM of beam leaving this component</doc>
        <dimensions size="2"><!-- [2,:] -->
            <dim index="1">2</dim>
            <dim index="2">:</dim>
        </dimensions>
    </field>
    <field name="flux" type="NX_FLOAT" units="NX_FLUX">
        <doc>flux incident on beam plane area</doc>
        <dimensions size="1">
            <dim index="1">i</dim>
        </dimensions>
    </field>
---------------------------------% clip here 
%---------------------------------



Pete Jemian wrote:
> Regarding the definition of dimensions, so far, so good.
> Now, here is part of (revised) NXbeam.nxdl.xml:
>
> ---------------------------------% clip here %---------------------------------
>    <field name="final_wavelength_spread" type="NX_FLOAT" units="NX_LENGTH">
>        <doc>Wavelength spread FWHM of beam leaving this component</doc>
>        <dimensions size="[:]" />
>    </field>
>    <field name="final_beam_divergence" type="NX_FLOAT" units="NX_ANGLE">
>        <doc>Divergence FWHM of beam leaving this component</doc>
>        <dimensions size="2"><!-- [2,:] --></dimensions>
>    </field>
>    <field name="flux" type="NX_FLOAT" units="NX_FLUX">
>        <doc>flux incident on beam plane area</doc>
>        <dimensions size="i" />
>    </field>
> ---------------------------------% clip here %---------------------------------
>
> How do we handle this?  (So far, it is valid by the changes in NXDL rules.)
> Also, we need better documentation strings than given below.
>
>
> (Here is just the revised part of nxdl.xsd):
> ---------------------------------% clip here %---------------------------------
>    <xs:complexType name="dimsType">
>        <!--
>            Here is a model:
>            <field name="data">
>                <dimensions size="3"/>
>                ...
>            </field><field name="time-of-flight">
>                <dimensions size="1">
>                    <dim index="1" ref="data" refindex="3" incr="1"/>
>                </dimensions>
>                ...
>            </field>
>           
>            In old terms this would make data[i,j,k] and time-of-flight[k+1].
>            We need to get to the stage where people
>            don't need to read a manual to understand an existing NXDL.
>        -->
>        <xs:annotation>
>            <xs:documentation>dimensions of a data element in a NeXus 
> file</xs:documentation>
>        </xs:annotation>
>        <xs:sequence>
>            <xs:element name="dim" minOccurs="0" maxOccurs="unbounded">
>                <xs:complexType>
>                    <xs:attribute name="index" type="nx:NX_CHAR">
>                        <xs:annotation>
>                            <xs:documentation>Number indicating which subscript is being referenced,
>                                ranging from 1 up to RANK (rank of the data structure).  For example,
>                                given an array A[i,j,k], index="1" would refer to the "i" subscript.</xs:documentation>
>                        </xs:annotation>
>                    </xs:attribute>
>                    <xs:attribute name="ref" type="nx:NX_CHAR">
>                        <xs:annotation>
>                            <xs:documentation>Name of the data structure being referenced 
>                                   indirectly.</xs:documentation>
>                        </xs:annotation>
>                    </xs:attribute>
>                    <xs:attribute name="refindex" type="nx:NX_CHAR">
>                        <xs:annotation>
>                            <xs:documentation>Index within the data structure being 
>                                  referenced indirectly.</xs:documentation>
>                        </xs:annotation>
>                    </xs:attribute>
>                    <xs:attribute name="incr" type="nx:NX_CHAR">
>                        <xs:annotation>
>                            <xs:documentation>What is this?</xs:documentation>
>                        </xs:annotation>
>                    </xs:attribute>
>                </xs:complexType>
>            </xs:element>
>        </xs:sequence>
>        <xs:attribute name="size" type="nx:NX_CHAR">
>            <xs:annotation>
>                <xs:documentation>Rank (number of dimensions) of the data structure. 
>                    For example: a[5] has size="1" while b[8,5,6,4] has size="4". 
>                    See http://en.wikipedia.org/wiki/Rank_(computer_programming)
>                    for more details.</xs:documentation>
>            </xs:annotation>
>        </xs:attribute>
>    </xs:complexType>
> ---------------------------------% clip here %---------------------------------
>
> Pete
>
>
>
>
>   

-- 
----------------------------------------------------------
  Pete R. Jemian, Ph.D.                <jemian at anl.gov>
  Beam line Controls and Data Acquisition, Group Leader
  Advanced Photon Source,   Argonne National Laboratory
  Argonne, IL  60439                   630 - 252 - 3189
-----------------------------------------------------------
     Education is the one thing for which people
        are willing to pay yet not receive.
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