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CHAPTER 3.
17
FIELDS AND VARIABLES
3.4 How to use eld references
It is quite common that dierent temporal operations must be applied to the
same instant data provided by the model. In theory, the only solution to handle
this scenario would be to dene a eld for each operation, give them dierent
id and and call xios_send_field with the same array of data for each of those
elds.
The following example illustrates this solution for a eld for which we want
to compute the average, minimal and maximal values:
<?
xml version=" 1 . 0 " ?>
< s i m u l a t i o n>
<c o n t e x t
i d=" t e s t ">
<c a l e n d a r
t y p e=" G r e g o r i a n "
t i m e s t e p=" 1 h "
/>
< g r i d _ d e f i n i t i o n>
i d=" grid_A ">< ! −−
<g r i d
Ç
Definition
ommited
−−></ g r i d
>
</ g r i d _ d e f i n i t i o n>
< f i l e _ d e f i n i t i o n>
<f i l e
name=" o u t p u t "
<f i e l d
Ç
<f i e l d
Ç
<f i e l d
Ç
o u t p u t _ f r e q=" 1 d ">
i d=" f i e l d _ A _ a v g "
g r i d _ r e f=" grid_A "
o p e r a t i o n=" a v e r a g e "
i d=" field_A_min "
o p e r a t i o n=" min "
/>
i d=" field_A_max "
o p e r a t i o n="max"
/>
g r i d _ r e f=" grid_A "
g r i d _ r e f=" grid_A "
/>
</ f i l e >
</ f i l e _ d e f i n i t i o n>
</ c o n t e x t>
</ s i m u l a t i o n>
To simplify the handling of such scenarios, XIOS has a reference feature which
allows one eld to inherit the attributes (except the
id) and the instant data of
another eld. The above example can then be rewritten:
<?
xml version=" 1 . 0 " ?>
< s i m u l a t i o n>
<c o n t e x t
i d=" t e s t ">
<c a l e n d a r
t y p e=" G r e g o r i a n "
t i m e s t e p=" 1 h "
/>
< g r i d _ d e f i n i t i o n>
<g r i d
Ç
i d=" grid_A ">< ! −−
Definition
ommited
>
</ g r i d _ d e f i n i t i o n>
< f i l e _ d e f i n i t i o n>
<f i l e
name=" o u t p u t "
o u t p u t _ f r e q=" 1 d ">
−−></ g r i d