[Rd] C code hanging and printing everything at the end

[Robert Lowe]

Hi,

I am currently writing an extension for R and have the need to include some C 
code. If I call the code with a large amount of data then it can take several 
minutes to complete.

The C code prints out after a certain iteration hence letting the user know it 
hasn't crashed.

When running in R this generally does not happen and all is printed out at the 
end once the program has completed successfully.

I am using Rprintf() to print out the required output.

e.g. Something simple which illustrates my point

for(int i=0; i<1; i++){
#Calculations
if (i%1000==0){
Rprintf("Step %d\n",i)
}
}

All I get during the program is the OS X spinning wheel in R. Is there any way 
to print out as the program is running?

Thanks,
Rob
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Re: [Rd] Dangerous Bug with IF function of R

[Robert Lowe]

> 
> I'm intrigued. After such a blatantly wrong claim about a bug in
> R...  what exactly are you claiming about Matlab here?
> That it implements (software) decimal arithmetic on top of the
> cpu-internal binary arithmetic ?   probably rather not ...
> 

Just for confirmation the same thing doesn't work in MATLAB as one would expect.

i=0;
for j=1:11
i=i+0.1;
if i==1
i
end
end

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Re: [Rd] Max likelihood using GPU

[Robert Lowe]

Hi Oyvind,

I believe this is possible to implement. There is already some work ongoing in 
using the GPU in R and they use the CUDA toolkit as the reference you supplied 
do.

http://brainarray.mbni.med.umich.edu/Brainarray/rgpgpu/

Thanks,
Rob


On 18 May 2011, at 10:07, oyvfos wrote:

> Dear all,
> Probably many of you experience long computation times when estimating large
> number of parameters using maximum likelihood  with functions that reguire
> numerical methods such as integration or root-finding. Maximum likelihood is
> an example of paralellization that could sucessfully utilize GPU. The
> general algorithm is described here:
> http://openlab-mu-internal.web.cern.ch/openlab-mu-internal/03_Documents/4_Presentations/Slides/2010-list/CHEP-Maximum-likelihood-fits-on-GPUs.pdf.
> Is it possible to implement this algorithm in R ? 
> Kind regards, Oyvind Foshaug
> 
> --
> View this message in context: 
> http://r.789695.n4.nabble.com/Max-likelihood-using-GPU-tp3532034p3532034.html
> Sent from the R devel mailing list archive at Nabble.com.
> 
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