[R] Calling R functions in Delphi

[Tom Backer Johnsen]

Anna Belova wrote:
> Hellp Tom,
> 
> Thank you so much!
> 
> Several people have helped by pointing us to using R as a COM server.  This
> is an exciting functionality, but unfortunately we are afraid we can't use
> it in this project.
> 
> I really appreciate your thought and your time.

The solution I suggested was not using R as a COM server, but calling 
R directly in a thread.  If you are using Delphi at all it should 
work.  So, I consider the suggestion to be good.

Besides, considering where your mail originates (a corporation), you 
might consider that I deserve a fee.  Do you want a bank account 
number?  Now, that might be difficult, considering that US bank 
systems are quite primitive by European standards, but nevertheless ...

Tom
> 
> Regards,
> Anna
> -----------------------------------------
> Anna Belova
> Abt Associates Inc.
> 4800 Montgomery Ln, St 600
> Bethesda, MD-20814
> phone: 301-347-5304
> fax: 301-652-7530
> http://www.abtassociates.com/environment
> 
> 
> 
>                                                                            
>              Tom Backer                                                    
>              Johnsen                                                       
>              <backer at psych.uib                                          To 
>              .no>                      Anna Belova                         
>                                        <Anna_Belova at abtassoc.com>          
>              12/05/2006 12:36                                           cc 
>              PM                        r-help at stat.math.ethz.ch            
>                                                                    Subject 
>                                        Re: [R] Calling R functions in      
>                                        Delphi                              
>                                                                            
>                                                                            
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>                                                                            
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> 
> 
> 
> Anna Belova wrote:
>> Hello All,
>>
>> We would like to call quantile() function from the R-package STATS in a
>> Delphi program. If this is possible, could anyone provide us with an
>> example?
> 
> It is possible, and in principle simple.  The essentials:  (1) Write a
> file containing the something like a script in R with whatever
> commands. (2) Start a process involving the execution of R with a
> command line containing two arguments, the name of the command file
> and the file where you want the output (results) to be. (3) wait for
> the process to stop.  So, here is a function (returns true if
> everyhing worked OK) that does that:
> 
> function StartRAndWait (CommandLine : string) : Boolean;
> var
>     Proc_info: TProcessInformation;
>     Startinfo: TStartupInfo;
>     ExitCode: longword;
>     CreateOK : Boolean;
> begin
>     Result := False;
> 
>     { Initialize the structures }
> 
>     FillChar(proc_info, sizeof (TProcessInformation), #0);
>     FillChar(startinfo, sizeof (TStartupInfo), #0);
>     Startinfo.cb := sizeof (TStartupInfo);
>     Startinfo.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
>     Startinfo.wShowWindow := SW_HIDE;
> 
>     { Attempt to create the process. If successful wait for it to end}
> 
>     CreateOK := CreateProcess(Nil, PChar('R.exe ' + CommandLine), nil,
>        nil,False, CREATE_NEW_PROCESS_GROUP+NORMAL_PRIORITY_CLASS, nil,
>        nil, StartInfo, proc_info);
>     if (CreateOK) then begin
>        WaitForSingleObject (proc_info.hProcess, INFINITE);
>        GetExitCodeProcess(proc_info.hProcess, ExitCode);
>        Result := True
>        end;
>     CloseHandle(proc_info.hThread);
>     CloseHandle(proc_info.hProcess);
>     end;
> 
> The argument for the procedure (CommandLine) is a string, created by a
> statement like:
> 
> Command := 'CMD BATCH ' + CommandFileName + ' ' + TempFileName;
> 
> where CommandFileName is the name of the file with the script, and
> TempFileName is the name of the text file containing the output. The
> procedure is fairly lowlevel, but it worked for me using Delphi 7.  I
> do not remember how I managed to put this together (probably a mix of
> help from the R and Delphi lists), so please do not ask questions
> about the finer details.
> 
> Tom
> 
> 
> +----------------------------------------------------------------+
> | Tom Backer Johnsen, Psychometrics Unit,  Faculty of Psychology |
> | University of Bergen, Christies gt. 12, N-5015 Bergen,  NORWAY |
> | Tel : +47-5558-9185                        Fax : +47-5558-9879 |
> | Email : backer at psych.uib.no    URL : http://www.galton.uib.no/ |
> +----------------------------------------------------------------+
> 
> 
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