Hello,
I'm facing a problem of optimization, I've already solved but I'm trying to
find other answers to this problem to improve the solution.
Well, to make it short: I have to set/install a number of devices in a
building, and I have to give service to a number of "customers", or better
say, to
> How about smoothing the percentages, and then take the second derrivative
to find the inflection point?
>
> which.max(diff(diff((lowess(percentages)$y
This solution is what I've been using so far. The only difference is that I
am smoothing the 1st derivative, since its the one I want to be s
Hello:
> Here is a general approach using smoothing using the Gasser-Mueller
kernel,
> which is implemented in the "lokern" package. The optimal bandwidth for
> derivative estimation is automatically chosen using a plug-in
approximation.
> The code and the results are attached here.
Maybe am I
>> How about smoothing the percentages, and then take the second
>> derrivative to find the inflection point?
>>
>> which.max(diff(diff((lowess(percentages)$y
>
> This solution is what I've been using so far. The only difference is that
I am smoothing the 1st derivative, since its
> the one
> I don't see why one would want to pretend that the function is continuous.
It isn't.
> The x variable devices is discrete.
> Moreover, the whole solution space is small: the possible solutions are
integers in the range of maybe 20-30.
Yes, you are right, what I'd like to think is that the outco
Hello,
Recently I have been trying to open a huge database with no success.
Its a 4GB csv plain text file with around 2000 rows and over 500,000
columns/variables.
I have try with The SAS System, but it reads only around 5000 columns, no
more. R hangs up when opening.
Is there any
Hello, Yihui
> You can treat it as a database and use ODBC to fetch data from the CSV
> file using SQL. See the package RODBC for details about database
> connections. (I have dealt with similar problems before with RODBC)
Thanks for your tip, I have used RODBC before to read data from MSAccess a
> I wouldn't call a 4GB csv text file a 'database'.
Obviously, a csv it's not a database itself, I tried to mean (though it
seems I was not understood) that I had a huge database, exported to csv file
by the people who created it (and I dont have any idea of the original
format of the database).
> Maybe you've not lurked on R-help for long enough :) Apologies!
Probably.
> So, how much "design" is in this data? If none, and what you've
> basically got is a 2000x50 grid of numbers, then maybe a more raw
Exactly, raw data, but a little more complex since all the 50 variables
are i
> What are you going to do with the data once you have read it in? Are
> all the data items numeric? If they are numeric, you would need at
> least 8GB to hold one copy and probably a machine with 32GB if you
> wanted to do any manipulation on the data.
Well, I will use only sets of variables to
> So is each line just ACCGTATAT etc etc?
Exacty, A_G, A_A, G_G and the such.
> If you have fixed width fields in a file, so that every line is the
> same length, then you can use random access methods to get to a
> particular value - just multiply the line length by the row number you
Nice hint
Hello:
I've been reading all the replies, and I think I have some good ideas to
work on.
Right now the code I programmed is running, It has been running in a batch
process 20h now, and It has imported 1750 rows out of 2000. I will read docs
for the bioconductor package, and I will check the gawk
12 matches
Mail list logo
