[kepler-users] how to add a complex fomula on Kepler

[Matthew Jones]

Hi Karen,

You probably will want to use one of the expression actors to calculate 
a complex formula.  Your main choices are:

Expression: allows arithmetic and statistical operations on data, 
including power functions and logarithms, that can be expressed as a 
single statement

RExpression: allows scripts of arbitrary complexity to be run on the R 
System for statistical computing, including simple arithmetic, vector 
and matrix operations, and complex statistical operations.  R is a 
full-featured scientific computing language.

MatlabExpresion: similar to the RExpression, but obviously depends on 
the Matlab system for its execution

Any of these systems should be able to do what you want. To use these, 
you just drag the appropriate actor to the canvas, add named input 
ports, and then create the expression referring to those named ports. 
For example, if you created input ports with names "x" and "y" you could 
write an expression like this:

log(x) + log(y)

and the output will be emitted on the output port.  With the RExpression 
actor you also create named output ports to map your script variables to 
the appropriate outputs.

Hope this helps.

Matt

Karen Tang wrote:
> Hi,
> 
> I am new in Kepler and  I need to have a complicated formula in the 
> workflow. The formula should take three inputs (web services' outputs), 
> do a complex calculation (including exponent, logrithm) then generate a 
> single value.
> 
> How can I add the formula in Kepler? Do I need to have this in a Java 
> class, then do it follow steps listed in your archived message 
> (http://mercury.nceas.ucsb.edu/ecoinformatics/pipermail/kepler-users/2006-March/000068.html)? 
> I couldn't succeed. Can you give more detailed instructions? An example 
> will be great.
> 
> My goal is to enable users(ocean scientists around the world) use 
> workflows I created. I am using Windows XP.
> 
> Thanks in advance.
> 
> Karen
> 
>  
>  
> 
> 
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-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Matthew B. Jones
jones at nceas.ucsb.edu                Ph: 541-888-2581 ext. 287
National Center for Ecological Analysis and Synthesis (NCEAS)
UC Santa Barbara
http://www.nceas.ucsb.edu/ecoinformatics
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~