Changes between Version 25 and Version 26 of LanguageChanges

Timestamp:

Mar 5, 2007, 12:51:50 PM (16 years ago)

Author:

Rafael de Pelegrini Soares

Comment:

Added comments about the final and DisplayUnit?

LanguageChanges

@@ -217 +217 @@
 ||Paula || '''agreed''' || I prefer single quote ||
 
+== Another UOM problems ==
+
+Currently EMSO support Units Of Measurement (UOM) for variables, parameters, equations, etc.
+But there is a potential problem when deriving types with a UOM:
+
+{{{
+#!mso
+Model MyModel
+    VARIABLES
+    P as pressure(Unit = 'm')
+    ...
+end
+}}}
+
+The above model has serious problems:
+ - '''P''' derived from a pressure type but has a ''length'' unit
+ - What about the limits if the UOM changed?
+
+In order to fix this kind of problem the following changes are proposed:
+ - add a '''final''' modifier for the attributes, preventing it to be changed
+ - add another attribute called '''DisplayUnit''', which should be compatible with '''Unit''' (the GUI will report all results converted to this UOM)
+ - the limits are considered to be in respect to the '''Unit''' and not '''DisplayUnit'''
+ - declare all UOM in '''types.mso''' as '''final'''
+
+Sample code in the with the propositions included:
+{{{
+#!mso
+# Pressure
+pressure as Real (Brief = "Pressure", Default=1, Lower=1e-30, Upper=5e7, final Unit = 'atm');
+press_delta as pressure (Brief = "Pressure Difference", Default=0.01, Lower=-5e6);
+head as Real (Brief = "Head", Default=50, Lower=-1e6, Upper=1e6, final Unit = 'kJ/kg');
+
+Model reactor
+  VARIABLES
+  C(NComp)      as conc_mol(Brief="Concentration", DisplayUnit='mol/l', Lower=0);
+  Co(NComp)     as conc_mol(Brief="Inlet concentration", DisplayUnit='mol/l', Lower=0);
+  ...
+end
+}}}
+
+
+||Who || Opinion || Why ||
+||Rafael || '''agreed''' || Proposed the change ||
+
 == OPTIONS section ==