Differences

This shows you the differences between two versions of the page.

--- fimex:todo:parameterfunction [2014-04-23 13:12:11]
heikok created
+++ fimex:todo:parameterfunction [2022-05-31 09:29:32] (current)
@@ Line 1: / Line 1: @@
-====== Project-Plan: easy function-based / parameter selection ======
+====== Project-Plan: easy function-based on demand parameter selection ======
+** currently moved to interal wiki for discussion  [[https://dokit.met.no/personal/it/heikok/fimex_parameterfunction]] **
 ===== Problem =====
@@ Line 5: / Line 7: @@
 Meteo. input data does not allways contain all parameters since gridded data usually is huge, while it is relatively easy to calculate them from other parameters, e.g. relative humidity <-> specific humidity. An end user just want to have 'his' parameter, independently if this is stored on disk or calculated on demand. Fimex currently does not support an easily configurable interface to support calculated parameters.
-[[http://diana.met.no|Diana]] supports on demand parameters in the FieldCompute setup. But FieldCompute can only be used from within diana and is as such restricted by Graphical Users, i.e. ~2s for display of data. And independent approach would avoid duplication and improve reliability if such on demand parameters could be added to all applications reading data via the fimex.
+[[http://diana.met.no|Diana]] supports on demand parameters in the FieldCompute setup. But FieldCompute can only be used from within diana and is as such restricted to graphical users requirements, i.e. ~2s for display of data. And independent approach would avoid duplication and improve reliability if such on demand parameters could be added to all applications reading data via the fimex.
 ===== Hard Requirements =====
@@ Line 15: / Line 17: @@
   * Users shall be able to switch on and off  on demand parameters.
   * It shall be possilbe to create an on-demand parameter from multiple CDMReader sources (as long as the data has the same grid)
-  * The system must work with both variable-names and CF standard_names and automatically select the first / best.
+  * The system shall work with both variable-names and CF standard_names and automatically select the first / best.
+  * The system shall be aware of units, both on input-data, as well as when requested for output.
 ===== Soft Requirements =====
@@ Line 22: / Line 25: @@
   * The software should have a clear separation from other fimex functionality, e.g. it should create a lib of its own, and it should reside in an own (sub-)catalog. It might be useful to integrate it into the fimex infrastruction, e.g. build / test infrastruction and even the same 'tar'-file (as long as the lib is a //configure// flag.)
+===== List over functions =====
+==== Constants ====
+  * PI
+FIXME
+==== Basic functions ====
+  * plus
+  * minus
+  * multiply
+  * devide
+  * exp
+  * log
+  * ln
+FIXME
+==== Meteorological functions ====
+FIXME
+==== Data representation ====
+  * vertical interpolation? (10m, 80m)
+  * column (sum over levels)
+  * accumulation (time)
+  * deaccumulation (time)
+FIXME
+===== Additional Information =====
+Diana field compute:
+<code>
+<FIELD_COMPUTE>
+# See diFieldFunctions.h or other documnetation
+geopotential_height_pl=divide(geopotential_pl,9.81)
+# computations in pressure levels (".plevel_")
+air_temperature_pl=tk.plevel_th(air_potential_temperature_pl)
+air_potential_temperature_pl=th.plevel_tk(air_temperature_pl:unit=kelvin)
+the_pl=the.plevel_tk_rh(air_temperature_pl:unit=kelvin,relative_humidity_pl:unit=0.01)
+the_pl=the.plevel_th_rh(air_potential_temperature_pl,relative_humidity_pl:unit=0.01)
+thesat_pl=thesat.plevel_th(air_potential_temperature_pl)
+thesat_pl=thesat.plevel_tk(air_temperature_pl:unit=kelvin)
+relative_humidity_pl=rh.plevel_tk_q(air_temperature_pl:unit=kelvin,specific_humidity_pl:unit=0.01)
+relative_humidity_pl=rh.plevel_th_q(air_potential_temperature_pl,specific_humidity_pl:unit=0.01)
+dew_point_temperature_pl=tdc.plevel_th_q(air_potential_temperature_pl,specific_humidity_pl:unit=0.01)
+dew_point_temperature_pl=tdc.plevel_tk_q(air_temperature_pl,specific_humidity_pl:unit=0.01)
+dew_point_temperature_pl=tdc.plevel_th_rh(air_potential_temperature_pl,relative_humidity_pl:unit=0.01)
+dew_point_temperature_pl=tdc.plevel_tk_rh(air_temperature_pl,relative_humidity_pl:unit=0.01)
+specific_humidity_pl=q.plevel_tk_rh(air_temperature_pl:unit=kelvin,relative_humidity_pl:unit=0.01)
+specific_humidity_pl=q.plevel_th_rh(air_potential_temperature_pl,relative_humidity_pl:unit=0.01)
+qvx_pl=qvector.plevel_z_th_xcomp(geopotential_height_pl,air_potential_temperature_pl)
+qvy_pl=qvector.plevel_z_th_ycomp(geopotential_height_pl,air_potential_temperature_pl)
+qvx_pl=qvector.plevel_z_tk_xcomp(geopotential_height_pl,air_temperature_pl:unit=kelvin)
+qvy_pl=qvector.plevel_z_tk_ycomp(geopotential_height_pl,air_temperature_pl:unit=kelvin)
+qvectorx_pl=multiply(qvx_pl,1.e+11)
+qvectory_pl=multiply(qvy_pl,1.e+11)
+qvector.divergence_pl=divergence(qvectorx_pl,qvectory_pl)
+ug_pl=geostrophic.wind.plevel_z_xcomp(geopotential_height_pl)
+vg_pl=geostrophic.wind.plevel_z_ycomp(geopotential_height_pl)
+uag_pl=subtract(x_wind_pl,ug_pl)
+vag_pl=subtract(y_wind_pl,vg_pl)
+</FIELD_COMPUTE>
+</code>