It worked fine for me without using much memory. Take a look at you
statements and you will see that you are missing a comma on the dimensions:
> n <- 58000
> max_out <- data.frame(Lat=runif(n), Long=runif(n), Model=sample(1:12, n
,TRUE),
+ Obs=sample(1:12, n, TRUE))
> str(max_out)
'data.frame': 58000 obs. of 4 variables:
$ Lat : num 0.266 0.372 0.573 0.908 0.202 ...
$ Long : num 0.295 0.286 0.989 0.413 0.924 ...
$ Model: int 2 6 5 3 1 3 2 12 6 3 ...
$ Obs : int 11 10 4 9 8 4 1 8 4 8 ...
> object.size(max_out)
1392576 bytes
> gc()
used (Mb) gc trigger (Mb) max used (Mb)
Ncells 126997 3.4 350000 9.4 350000 9.4
Vcells 256113 2.0 1091825 8.4 1028962 7.9
> # notice additional commas
> value <- cbind(max_out,
+ dif=ifelse(max_out[,3] - max_out[,4]> 6, max_out[,3] -
(max_out[,4]+12), max_out[,3] - max_out[,4]))
> str(value)
'data.frame': 58000 obs. of 5 variables:
$ Lat : num 0.266 0.372 0.573 0.908 0.202 ...
$ Long : num 0.295 0.286 0.989 0.413 0.924 ...
$ Model: int 2 6 5 3 1 3 2 12 6 3 ...
$ Obs : int 11 10 4 9 8 4 1 8 4 8 ...
$ dif : num -9 -4 1 -6 -7 -1 1 4 2 -5 ...
> head(value,20)
Lat Long Model Obs dif
1 0.26550866 0.29545897 2 11 -9
2 0.37212390 0.28644093 6 10 -4
3 0.57285336 0.98867753 5 4 1
4 0.90820779 0.41280923 3 9 -6
5 0.20168193 0.92394115 1 8 -7
6 0.89838968 0.51848851 3 4 -1
7 0.94467527 0.71813809 2 1 1
8 0.66079779 0.78323081 12 8 4
9 0.62911404 0.84581027 6 4 2
10 0.06178627 0.01757108 3 8 -5
11 0.20597457 0.39770773 11 6 5
12 0.17655675 0.62580029 7 4 3
13 0.68702285 0.44794291 2 8 -6
14 0.38410372 0.08462264 7 8 -1
15 0.76984142 0.98978339 6 7 -1
16 0.49769924 0.42655140 12 2 -2
17 0.71761851 0.03631297 11 6 5
18 0.99190609 0.04994102 7 5 2
19 0.38003518 0.79581617 1 2 -1
20 0.77744522 0.40658383 9 6 3
> gc()
used (Mb) gc trigger (Mb) max used (Mb)
Ncells 129604 3.5 350000 9.4 350000 9.4
Vcells 488484 3.8 1610438 12.3 1605598 12.3
>
> # error -- not run-- Incorrect indexing
> #--value_err <- cbind(max_out,
> #-- dif=ifelse(max_out[3] - max_out[4]> 6, max_out[3] -
(max_out[4]+12), max_out[3] - max_out[4]))
>
>
On Mon, May 25, 2009 at 11:00 AM, Steve Murray <smurray...@hotmail.com>wrote:
>
> Dear R Users,
>
> I have a data frame of 4 columns and ~58000 rows, the top of which looks
> like this:
>
> > head(max_out)
> Latitude Longitude Model Obs
> 1 -0.25 -49.25 4 4
> 2 -0.25 -50.25 4 5
> 3 -0.25 -50.75 4 4
> 4 -0.25 -51.25 3 11
> 5 -0.25 -51.75 6 4
> 6 -0.25 -52.25 12 5
>
> The above shows, for each coordinate point, the month (1 = January, 12 =
> December) in which the maximum value occurs for the variable I'm testing.
>
> I'm hoping to add an extra column onto this data frame to show the
> difference between the model and the observations, in the form of:
> max_out[3] - max_out[4].
>
> This is fine for the simple cases, but row 6 is an example where this
> approach fails. I know from the data that model is predicting the maximum
> value too early (i.e. -5 months) rather than 7 months too late (as implied
> by the simple max_out[3] - max_out[4] calculation).
>
> In order to get round such cases, if the result of the simple calculation
> is>6, then I want to add 12 to the offending value (!) in the 'Obs' column
> in order to get the 'correct' value. For example, in row 6, as the current
> calculation results in a difference of 7, I instead want to do 12-(5+12)
> (corresponding to Obs+12 - Model) = -5.
>
> Similarly, in row 4, I'd like to do the reverse (i.e. -12 for where the
> calculation results in a value <- cbind(max_out[1:2], ifelse(max_out[3] -
> max_out[4]> 6, max_out[3] - (max_out[4]+12), max_out[3] - max_out[4])) # If
> diff is not>6, then output original difference value
>
> Error: cannot allocate vector of size 221 Kb
> In addition: Warning messages:
> 1: In data.frame(..., check.names = FALSE) :
> Reached total allocation of 999Mb: see help(memory.size)
> 2: In data.frame(..., check.names = FALSE) :
> Reached total allocation of 999Mb: see help(memory.size)
>
>
> I suspect I'm doing something wrong, as the calculation shouldn't be that
> computationally intense!
>
>
> Any help or advice to help get me on the right tracks would be much
> appreciated.
>
> Many thanks,
>
> Steve
>
>
>
> _________________________________________________________________
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>
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
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