For those who are interested. Anyone care to comment? I have no idea the performance gap on simple i/o can be that big...
Andy From: Jason Fisher [mailto:[EMAIL PROTECTED] Sent: Wednesday, February 26, 2003 3:44 PM To: [EMAIL PROTECTED] Subject: RE: [R] DLL Advice Hi Andy... Comparing apples to apples really clarified things. g77 -> 58 seconds to run Visual FORTRAN -> 3.5 seconds to run Wow! I bet g77 and Visual FORTRAN handle read statements differently. My program is pretty simplistic. Open a massive text file (323,063 KB) and read a few key pieces of information spread evenly throughout the file. Thanks Again, J *************************************** Jason C. Fisher UCLA Graduate Student Civil & Environmental Engineering Dept. 5731 Boelter Hall Box 951593 Los Angeles, CA 90095-1593 Phone Number: (310) 825-2292 Email: [EMAIL PROTECTED] *************************************** >From: "Liaw, Andy" <[EMAIL PROTECTED]> >To: "'Jason Fisher'" <[EMAIL PROTECTED]> >Subject: RE: [R] DLL Advice >Date: Wed, 26 Feb 2003 15:10:24 -0500 > >You may want to try comparing apple to apple first. Try compiling your >code >to .exe using the MinGW g77 and see how that fares with the .exe you get >with Visual Fortran. I strongly suspect that what you're seeing is due in >large part to the difference in g77 and visual fortran. > >g77 is known to be at best OK when it comes to performance. The problem is >that on Windows you don't have much of a choice. > >Andy > > > -----Original Message----- > > From: Jason Fisher [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, February 26, 2003 2:57 PM > > To: [EMAIL PROTECTED] > > Subject: [R] DLL Advice > > > > > > Hi All... > > > > A few questions concerning the use of DLLs in R. Before you > > get scared off > > and don't read any further (I've seen a lot of talk within > > the help pages > > concerning loading DLLs in R) realize that communication > > between R and my > > DLLs is solid. The problem arises when comparing the computational > > performance between calling a *.dll file, compiled using g77 > > under MinGW > > version 2.0.0 with package upgrades, and calling an *.exe > > file, compiled > > with Compaq Visual FORTRAN Professional Edition 6.6.A. Both > > calls (.Fortran > > and system) are made from the R - Tcl/Tk GUI environment. > > After comparing > > identical code, compiled as a DLL and EXE, I've come to the > > disappointing > > realization that the DLL calls take about five times the > > computational time > > of the EXE calls. I tried the experiment using a number of different > > FORTRAN codes with the same results. > > > > My first thought was that I was compiling the code incorrectly. The > > following command is what I typically use to generate the DLL. > > > > g77 -shared -o temp.dll temp.f > > > > After a short search over the net, I discovered a number of > > g77 optimization > > options (e.g. -O, -O2) for compiling. These options had > > little to no impact > > on the computational times. Next, I went back to "Writing R > > Extensions" and > > started working with the Rcmd SHLIB. This again had little > > to no impact on > > computational time. > > > > Any ideas, I'm a novice at working with DLLs and know there must be > > something I'm missing. One option is to just call the EXE, > > however, it just > > seems crummy to generate an input file in R, run the EXE > > which produces an > > output file, read the EXE output file in R, and finally > > delete the input > > and output files. > > > > Thanks in advance for any insightful knowledge you bring my way. > > > > Regards, > > Jason > > > > R 1.6.2 > > > > *************************************** > > Jason C. Fisher > > UCLA Graduate Student > > Civil & Environmental Engineering Dept. > > 5731 Boelter Hall > > Box 951593 > > Los Angeles, CA 90095-1593 > > Phone Number: (310) 825-2292 > > Email: [EMAIL PROTECTED] > > > > ______________________________________________ > > [EMAIL PROTECTED] mailing list > > http://www.stat.math.ethz.ch/mailman/listinfo/r-help > > > >--------------------------------------------------------------------------- --- >Notice: This e-mail message, together with any attachments, contains >information of Merck & Co., Inc. (Whitehouse Station, New Jersey, USA) that >may be confidential, proprietary copyrighted and/or legally privileged, and >is intended solely for the use of the individual or entity named on this >message. If you are not the intended recipient, and have received this >message in error, please immediately return this by e-mail and then delete >it. > >=========================================================================== === > _________________________________________________________________ ------------------------------------------------------------------------------ ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help
