Read in Formula via Dictionary

hxaxtma · January 23, 2016, 08:43

Hi guys,

quick question, I created an own Dict and reading in a formular via

Code:

word    cd(word(sensorDict.subDict("solving").lookup("cd")));

where cd is defined in the dict as:

Code:

cd            "1+10*Foam::exp(Re,0.66666667)";

Next I want to use this relation in my main loop, so I need to convert this word string to what exactly?

Thanks for help

hxaxtma · January 25, 2016, 04:28

Hi, I tried with

Code:

 #include <cstdlib>
scalar cd_form=atof(cd.c_str());

Code is now compiling and it is printing the formula as string, but not using it as mathematical operator.

Any ideas?

chriss85 · January 25, 2016, 04:29

This means you will need to have a parser/interpreter. I'm not sure if there is one in OpenFOAM, yiou might have some luck with swak4Foam though.

marupio · January 27, 2016, 12:47

I think you might want equationReader.

swak4Foam could be suitable, but if you want to parse a user-entered equation and use it at your discretion within your application, then that is exactly what equationReader was intended for. Be careful, though... any interpreted equations will take longer to evaluate than hard-coded equations.

January 23, 2016, 08:43	Read in Formula via Dictionary	#1
hxaxtma Senior Member Join Date: Jan 2014 Posts: 179 Rep Power: 12	Hi guys, quick question, I created an own Dict and reading in a formular via Code: word cd(word(sensorDict.subDict("solving").lookup("cd"))); where cd is defined in the dict as: Code: cd "1+10*Foam::exp(Re,0.66666667)"; Next I want to use this relation in my main loop, so I need to convert this word string to what exactly? Thanks for help

January 25, 2016, 04:28		#2
hxaxtma Senior Member Join Date: Jan 2014 Posts: 179 Rep Power: 12	Hi, I tried with Code: #include <cstdlib> scalar cd_form=atof(cd.c_str()); Code is now compiling and it is printing the formula as string, but not using it as mathematical operator. Any ideas?

January 27, 2016, 12:47		#4
marupio Senior Member David Gaden Join Date: Apr 2009 Location: Winnipeg, Canada Posts: 437 Rep Power: 22	I think you might want equationReader. swak4Foam could be suitable, but if you want to parse a user-entered equation and use it at your discretion within your application, then that is exactly what equationReader was intended for. Be careful, though... any interpreted equations will take longer to evaluate than hard-coded equations. __________________ ~~~ Follow me on twitter @DavidGaden

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January 25, 2016, 04:29		#3
chriss85 Senior Member Join Date: Oct 2013 Posts: 397 Rep Power: 19	This means you will need to have a parser/interpreter. I'm not sure if there is one in OpenFOAM, yiou might have some luck with swak4Foam though.