R help - Nov 2012 - loop function and integrate?

Hi guys! 
I have to compute something and i don't know what i'm doing wrong. my
code
is a bit complex, but imagine that is something like this: 

a = c(1,2,3,4) 
ia = length(a) 

x = seq(1,100,length=0.1) 
ib = length(x) 

int1 = numeric(ib) 
b = numeric(ib) 

for(j in 1:ia) { 
   H = function(x) {sin(x + a[j])} 
      for(i in 1:ib) {	
                int =  integrate(H, lower = 0, upper = x[i]) 
                int1[i] = int[1] 
                b[i] = 1 + a[i] 
                } 
        end 
   int1 = unlist(int1) 
   int2 = int1*b 
   ss[j] = sum(int2) 
} 
end 

if i try this code without the for loop it's ok, but when i put the for on,
i get all sort of errors... 
Thank you for your help :) 



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Now i've managed to do this:

funcs <- list()
funcs[]

# loop through to define functions
for(i in 1:ib-1){

    # Make function name
    funcName <- paste( 'func', i, sep = '' )

    # make function
    func = paste('function(x){sin(x + a[', i,'])))}',sep =
'')

    funcs[[funcName]] = eval(parse(text=func))
  

    }
end

but still cant apply the integrate in a loop for all the different
functions..... :/
help me out guys.... pretty please :)



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Hello,

Your code doesn't run without initializing 'ss' to something. And
I've
made some changes, but I don't understand what you are trying to do. See 
comments inline.


a = c(1,2,3,4)
ia = length(a)

x = seq(1, 100, by=0.1)   # It was 'length = 0.1' (!)
ib = length(x)

ss <- numeric(ia)  # New, 'ss' must exist.
int1 = numeric(ib)
b = numeric(ib)

for(j in 1:ia) {
     H = function(x) {sin(x + a[j])}
     for(i in 1:ib) {
         int =  integrate(H, lower = 0, upper = x[i])
         int1[i] = int[1]
         b[i] = 1 + a[j]   # It was 'a[i]', didn't make any sense.
     }
     int1 = unlist(int1)
     int2 = int1*b
     ss[j] = sum(int2)
}
ss


And for loops (or any other type of loops) do _not_ end with 'end'.

Hope this helps,

Rui Barradas

Em 30-11-2012 15:08, faeriewhisper escreveu:
> Hi guys!
> I have to compute something and i don't know what i'm doing wrong.
my code
> is a bit complex, but imagine that is something like this:
>
> a = c(1,2,3,4)
> ia = length(a)
>
> x = seq(1,100,length=0.1)
> ib = length(x)
>
> int1 = numeric(ib)
> b = numeric(ib)
>
> for(j in 1:ia) {
>     H = function(x) {sin(x + a[j])}
>        for(i in 1:ib) {	
>                  int =  integrate(H, lower = 0, upper = x[i])
>                  int1[i] = int[1]
>                  b[i] = 1 + a[i]
>                  }
>          end
>     int1 = unlist(int1)
>     int2 = int1*b
>     ss[j] = sum(int2)
> }
> end
>
> if i try this code without the for loop it's ok, but when i put the for
on,
> i get all sort of errors...
> Thank you for your help :)
>
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/loop-function-and-integrate-tp4651436.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.

On 30-11-2012, at 16:08, faeriewhisper wrote:
> Hi guys! 
> I have to compute something and i don't know what i'm doing wrong.
my code
> is a bit complex, but imagine that is something like this: 
> 
> a = c(1,2,3,4) 
> ia = length(a) 
> 
> x = seq(1,100,length=0.1) 
> ib = length(x) 
> 
> int1 = numeric(ib) 
> b = numeric(ib) 
> 
> for(j in 1:ia) { 
>   H = function(x) {sin(x + a[j])} 
>      for(i in 1:ib) {	
>                int =  integrate(H, lower = 0, upper = x[i]) 
>                int1[i] = int[1] 
>                b[i] = 1 + a[i] 
>                } 
>        end 
>   int1 = unlist(int1) 
>   int2 = int1*b 
>   ss[j] = sum(int2) 
> } 
> end 
> 
What are you doing?
What's the "end" doing in your code in two places.
end is a function to extract and encode the last observation of a time series
object. See ?end
It makes absolutely no sense to put them in your code.
Remove them immediately.

You haven't declared ss to be a vector.
So before the start of the j loop insert ss <- numeric(ia)

And simplify your code:

ss <- numeric(ia)

for(j in 1:ia) { 
  H = function(x) {sin(x + a[j])} 
     for(i in 1:ib) {	
               int =  integrate(H, lower = 0, upper = x[i])  
               int1[i] = int$value
               b[i] = 1 + a[i] 
               }
  ss[j] = sum(int1*b)    
} 
ss

And more simplification is possible by eliminating b, which I leave to you.

Berend