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Jonsson

2012-Apr-27 15:46 UTC

[R] Min , Max

Hellow everyone,
This code bellow will calculate average daily wind speed(measurements are
taken every three hours).Any ideas how to take the Min and Max instead of
average.

library(Matrix)
setwd("C:\\Users\\aalyaari\\Desktop\\img")
listfile<-dir()
long <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\inra.bin", "rb")
 A=readBin(long, integer(), size=2,n=67420*1, signed=F)
 ta<-t(A)
 lot <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\lat.img", "rb")
 B=readBin(lot, integer(), size=2,n=67420*1, signed=F)
 tb<-t(B)

for (n in 1:length(listfile))
{
    
	#h[n]=listfile[n]
	h=listfile[n]
    	#b[n]=file.info(h[n])$size/67420/4
	b=file.info(h[n])$size/67420/4

 	wind <- file(h, "rb")
 	C=readBin(wind, double(), size=4,n=67420*b, signed=TRUE)
 
 	D<-matrix(C,nrow=b,ncol=67420)
 
	for(d in 1:b)
 	{
	 	M <- Matrix(-9999, 360, 720)
       	tm<-t(M)
	 	for(i in 1:67420)
	 	{
			tm[ta[i],tb[i]]= round(10 * ((D[(d-1)*8+1,i] + D[(d-1)*8+2,i]
+D[(d-1)*8+3,i] +D[(d-1)*8+4,i] +D[(d-1)*8+5,i] +D[(d-1)*8+6,i]
+D[(d-1)*8+7,i] +D[(d-1)*8+8,i] ) / 8))
	
	 	}
	 	to.write <- sprintf("C:\\Users\\aalyaari\\Desktop\\New folder
(6)\\Yar_%00d.bin", d)
	 	writeBin(as.integer(tm at x), size=2,to.write)
 	}
}


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Rui Barradas

2012-Apr-27 16:14 UTC

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[R] Min , Max

Hello,


Jonsson wrote> 
> Hellow everyone,
> This code bellow will calculate average daily wind speed(measurements are
> taken every three hours).Any ideas how to take the Min and Max instead of
> average.
> 
> library(Matrix)
> setwd("C:\\Users\\aalyaari\\Desktop\\img")
> listfile<-dir()
> long <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\inra.bin",
> "rb")
>  A=readBin(long, integer(), size=2,n=67420*1, signed=F)
>  ta<-t(A)
>  lot <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\lat.img",
> "rb")
>  B=readBin(lot, integer(), size=2,n=67420*1, signed=F)
>  tb<-t(B)
> 
> for (n in 1:length(listfile))
> {
>     
> 	#h[n]=listfile[n]
> 	h=listfile[n]
>     	#b[n]=file.info(h[n])$size/67420/4
> 	b=file.info(h[n])$size/67420/4
> 
>  	wind <- file(h, "rb")
>  	C=readBin(wind, double(), size=4,n=67420*b, signed=TRUE)
>  
>  	D<-matrix(C,nrow=b,ncol=67420)
>  
> 	for(d in 1:b)
>  	{
> 	 	M <- Matrix(-9999, 360, 720)
>        	tm<-t(M)
> 	 	for(i in 1:67420)
> 	 	{
> 			tm[ta[i],tb[i]]= round(10 * ((D[(d-1)*8+1,i] + D[(d-1)*8+2,i]
> +D[(d-1)*8+3,i] +D[(d-1)*8+4,i] +D[(d-1)*8+5,i] +D[(d-1)*8+6,i]
> +D[(d-1)*8+7,i] +D[(d-1)*8+8,i] ) / 8))
> 	
> 	 	}
> 	 	to.write <- sprintf("C:\\Users\\aalyaari\\Desktop\\New folder
> (6)\\Yar_%00d.bin", d)
> 	 	writeBin(as.integer(tm at x), size=2,to.write)
>  	}
> }
> 
Your code line with 'round', near the bottom, is equivalent to this
simpler
line:

tm[ta[i],tb[i]]= round(10 * sum(D[(d-1)*8 + 1:8, i]) / 8)

Note that this doesn't give the average, but the average multiplied by 10.
For the average, with and without the factor 10, use

tm[ta[i],tb[i]]= round(10 * mean(D[(d-1)*8 + 1:8, i]))
tm[ta[i],tb[i]]= round(mean(D[(d-1)*8 + 1:8, i]))

(Why not use the parameter 'digits'?)
tm[ta[i],tb[i]]= round(mean(D[(d-1)*8 + 1:8, i]), 1)

Now just substitute min or max for mean.

Hope this helps,

Rui Barradas



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Jonsson

2012-Apr-27 16:31 UTC

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[R] Min , Max

Dear Rui,

I really appreciate your help. This is exactly what I was looking for.I know
there is simpler way than mine but I couldn't figure it out.So, many many
thanks.

I wonder what is the difference between 

This:    tm[ta[i],tb[i]]= round(mean(D[(d-1)*8 + 1:8, i])) 
 and This:  (Why not use the parameter 'digits'?) 
tm[ta[i],tb[i]]= round(mean(D[(d-1)*8 + 1:8, i]), 1) 



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R. Michael Weylandt

2012-Apr-27 16:32 UTC

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[R] Min , Max

You might want to look into the caTools package: it provides runmean,
runmin, and runmax functions -- if you set those for a window of
length 8 and then take every 8th element, you should get what you're
looking for (much cleaner and faster too!) A good way to do that
subset is something like:

x <- 1:100
y <- x^2 - 3*x + 5
n <- 8

y[!(seq_along(x) %% n)]

Though I'm pretty sure I've seen a cleaner version elsewhere....

Michael

On Fri, Apr 27, 2012 at 11:46 AM, Jonsson <amen.alyaari at
bordeaux.inra.fr> wrote:> Hellow everyone,
> This code bellow will calculate average daily wind speed(measurements are
> taken every three hours).Any ideas how to take the Min and Max instead of
> average.
>
> library(Matrix)
> setwd("C:\\Users\\aalyaari\\Desktop\\img")
> listfile<-dir()
> long <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\inra.bin", "rb")
> ?A=readBin(long, integer(), size=2,n=67420*1, signed=F)
> ?ta<-t(A)
> ?lot <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\lat.img", "rb")
> ?B=readBin(lot, integer(), size=2,n=67420*1, signed=F)
> ?tb<-t(B)
>
> for (n in 1:length(listfile))
> {
>
> ? ? ? ?#h[n]=listfile[n]
> ? ? ? ?h=listfile[n]
> ? ? ? ?#b[n]=file.info(h[n])$size/67420/4
> ? ? ? ?b=file.info(h[n])$size/67420/4
>
> ? ? ? ?wind <- file(h, "rb")
> ? ? ? ?C=readBin(wind, double(), size=4,n=67420*b, signed=TRUE)
>
> ? ? ? ?D<-matrix(C,nrow=b,ncol=67420)
>
> ? ? ? ?for(d in 1:b)
> ? ? ? ?{
> ? ? ? ? ? ? ? ?M <- Matrix(-9999, 360, 720)
> ? ? ? ?tm<-t(M)
> ? ? ? ? ? ? ? ?for(i in 1:67420)
> ? ? ? ? ? ? ? ?{
> ? ? ? ? ? ? ? ? ? ? ? ?tm[ta[i],tb[i]]= round(10 * ((D[(d-1)*8+1,i] +
D[(d-1)*8+2,i]
> +D[(d-1)*8+3,i] +D[(d-1)*8+4,i] +D[(d-1)*8+5,i] +D[(d-1)*8+6,i]
> +D[(d-1)*8+7,i] +D[(d-1)*8+8,i] ) / 8))
>
> ? ? ? ? ? ? ? ?}
> ? ? ? ? ? ? ? ?to.write <-
sprintf("C:\\Users\\aalyaari\\Desktop\\New folder
> (6)\\Yar_%00d.bin", d)
> ? ? ? ? ? ? ? ?writeBin(as.integer(tm at x), size=2,to.write)
> ? ? ? ?}
> }
>
>
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> View this message in context:
http://r.789695.n4.nabble.com/Min-Max-tp4593065p4593065.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Jonsson

2012-Apr-28 13:54 UTC

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[R] Min , Max

This code bellow will calculate average daily wind speed(measurements are
taken every three hours).

library(Matrix) 
setwd("C:\\Users\\aalyaari\\Desktop\\img") 
listfile<-dir() 
long <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\inra.bin", "rb")
 A=readBin(long, integer(), size=2,n=67420*1, signed=F) 
 ta<-t(A) 
 lot <- file("C:\\Users\\aalyaari\\Desktop\\New folder
(5)\\lat.img", "rb")
 B=readBin(lot, integer(), size=2,n=67420*1, signed=F) 
 tb<-t(B) 

for (n in 1:length(listfile)) 
{ 
    
        #h[n]=listfile[n] 
        h=listfile[n] 
    #b[n]=file.info(h[n])$size/67420/4 
        b=file.info(h[n])$size/67420/4 

 	wind <- file(h, "rb") 
 	C=readBin(wind, double(), size=4,n=67420*b, signed=TRUE) 
  
 	D<-matrix(C,nrow=b,ncol=67420) 
  
        for(d in 1:b) 
 	{ 
         	M <- Matrix(-9999, 360, 720) 
       	tm<-t(M) 
         	for(i in 1:67420) 
         	{ 
                       tm[ta[i],tb[i]]= round(10 * mean(D[(d-1)*8 + 1:8),
i])
        
         	} 
         	to.write <- sprintf("C:\\Users\\aalyaari\\Desktop\\New folder
(6)\\Yar_%00d.bin", d) 
         	writeBin(as.integer(tm at x), size=2,to.write) 
 	} 
}



the values are measured in kelvin so i want to convert them to
degree,therefor I want to subtract all values by 273.15 before talking the
average or max.... but did not work.In other words, i want this: every value
is subtracted by 273.15 first ,then do other calculations(Min, Max)Can
anyone tell me what is wrong.Thanks

tm[ta[i],tb[i]]= round(10 * mean(D[((d-1)*8 + 1:8)-273.15), i])) 

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David Winsemius

2012-Apr-28 18:53 UTC

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[R] Min , Max

On Apr 28, 2012, at 11:51 AM, Jonsson wrote:
> Dear David, I think you meant
tm[ta[i],tb[i]]= round(10 * mean(D[((d-1)*8 + 1:8),i]-273.15))  not

tm[ta[i],tb[i]]= round(10 * mean(D[((d-1)*8 + 1:8)-273.15),  
i]-273.15)) .>
> As you can see  in the code above.I want to save the results as
> integer(16bit) thats why  I multiplied by 10(as factor),in order to  
> keep one
> dice-mil . Because I will later divide by 10.for example if I got 25  
> so this
> means 2.5. Thats why I used round.

Yes that is what I meant.

-- 
David Winsemius, MD
Heritage Laboratories
West Hartford, CT

Rui Barradas

2012-Apr-28 23:12 UTC

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[R] Min , Max

Hello,
>
> Yes ,It worked. So how can I insert it in my code? Please
>
Simply like this:

#for (n in 1:length(listfile))
#{
#	h=listfile[n]
#
for(h in listfile)
{

Rui Barradas


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