# Decomposition (Was: Re: Philosophy of basic Q (Was: Re: [QUANTITY] Data Model for Quantity v0.5

Pierre Didelon pdidelon at cea.fr
Wed May 12 01:05:45 PDT 2004

```Hi Brian,

some details which I don't understand,
may be related once more to document contradiction?

Brian Thomas wrote:

> 	David,
>
snip
>
> 	What I am suggesting is that the higher dimensional Q's (core, standard)
> 	be allowed to be "decomposed" into a set of basic Q's which hold the equivalent
> 	information. In code, this looks like :
>
> 	List decomposedBasicQList = standardQ.decompose();
>
> 	In terms of the equivalence principle in the meta-data/data, it is best
> 	explained via example. Take a standard Quantity with a coordinate
> 	description, say Counts(x_pixel) ("counts as a function of x_pixel quantity):
>
> 	<quantity name="counts">
> 			<quantity name="obs time"><units>hr</units><string/><value>3:00</value></quantity>
> 		<axes>
> 			<quantity name="x_pixel"><units>pixel</units><integer width="1"/><values>0 1 2</values></quantity>
> 		</axes>
> 		<units>cnts</units>
> 		<float width="4" precision="1"/>
> 		<values>10.2 39.8 40.5</values>
> 	</quantity>
>
> 	has the equivalent description in basic Q's (abbreviated the node name to "bq") as:
>
> 	<!-- the first pixel as bq -->
> 	<bq name="counts">
> 			<bq name="obs time"><units>hr</units><string/><value>3:00</value></bq>
> 			<bq name="x_pixel"><units>pixel</units><integer width="1"/><value>0</value></quantity>
> 		<units>cnts</units>
> 		<float width="4" precision="1"/>
> 		<value>10.2</value>
> 	</bq>
>

In Doc. MetaData is "related" to CoreQuantity level,
so does the above example be allowed in this case?
But may be your are using xsd files (which I read through xsd schema)
which seems to allow optionnal metadata at every levels!
I don't understand the relation of xsd file and graph. with document!

Pierre

```