Using SVD on each matrix in a list - r

I'm trying to use the svd() function on all matrices within a list. Currently, the results only appear for the first matrix in the list. How can this be done for every matrix in the list?
svd_list <- function(data) {
for (i in 1:length(data)) {
svd <- svd(data[[i]])
return(svd$d)
}
}

You are over writing the results in svd in each iteration. Initialise an empty list to store the results.
svd_list <- function(data) {
svd <- vector('list', length(data))
for (i in 1:length(data)) {
svd[[i]] <- svd(data[[i]])$d
}
return(svd)
}
Alternatively, you can use lapply :
svd_list <- function(data) {
lapply(data, function(x) svd(x)$d)
}

Related

Apply a function to objects in my global environment R

This code chunk creates a 10 objects based of length of alpha.
alpha <- seq(.1,1,by=.1)
for (i in 1:length(alpha)){
assign(paste0("list_ts_ses_tune", i),NULL)
}
How do I put each function into the new list_ts_ses_tune1 ... null objects I've created? Each function puts in a list, and works if I set list_ts_ses_tune1 <- lapply ...
for (i in 1:length(alpha))
{
list_ts_ses_tune[i] <- lapply(list_ts, function(x)
forecast::forecast(ses(x,h=24,alpha=alpha[i])))
list_ts_ses_tune[i] <- lapply(list_ts_ses_tune[i], "[", c("mean"))
}
Maybe this is a better way to do this? I need each individual output in a list of values.
Edit:
for (i in 1:length(alpha))
{
list_ts_ses_tune[[i]] <- lapply(list_ts[1:(length(list_ts)/2)],
function(x)
forecast::forecast(ses(x,h=24,alpha=alpha[i])))
list_ts_ses_tune[[i]] <- lapply(list_ts_ses_tune[[i]], "[", c("mean"))
}
We can use mget to return all the objects into a list
mget(ls(pattern = '^list_ts_ses_tune\\d+'))
Also, the NULL list can be created more easily instead of 10 objects in the global environment
list_ts_ses_tune <- vector('list', length(alpha))
Now, we can just use the OP's code
for (i in 1:length(alpha))
{
list_ts_ses_tune[[i]] <- lapply(list_ts, function(x)
forecast::forecast(ses(x,h=24,alpha=alpha[i])))
}
If we want to create a single data.frame
for(i in seq_along(alpha)) {
list_ts_ses_tune[[i]] <- data.frame(Mean = do.call(rbind, lapply(list_ts, function(x)
forecast::forecast(ses(x,h=24,alpha=alpha[i]))$mean)))
}
You could simply accomplish everything by doing:
library(forecast)
list_ts_ses_tune <- Map(function(x)
lapply(alpha, function(y)forecast(ses(x,h=24,alpha=y))['mean']), list_ts)

list of dataframes in R: assignment problem

I have the following code:
child_tracks <- list()
for(i in 1:106)
{
for(j in 1:5)
{
child_tracks[[i]][[j]] <-
all_samples[[i]][sample(nrow(all_samples[[i]]),length_breakups[[i]][[j]]),]
}
}
As above, "all_samples" is a list of dataframes, while "length_breakups" is a list of lists.
When I assign the calculation to it, it throws an error
: subscript out of bounds. Although a singular variable can hold, a list
can't. For example:
temp <-
all_samples[[i]][sample(nrow(all_samples[[i]]),length_breakups[[i]][[j]]),]
child_tracks[[i]][[j]] <-
all_samples[[i]][sample(nrow(all_samples[[i]]),length_breakups[[i]][[j]]),]
The former works, the latter doesn't. I've seen that the class
definitions are all okay and so are the ranges of the "for" loop.
Just not getting around it. Any comments?
Initialise the size of the list:
child_tracks <- array(list(), c(106,5))
for(i in 1:106)
{
for(j in 1:5)
{
child_tracks[[i]][[j]] <-
all_samples[[i]][sample(nrow(all_samples[[i]]),length_breakups[[i]][[j]]),]
}
}

R - Fill the arguments of a function in an ellipsis

I have the following function :
ExampleFunction <- function(ListNumber1, ListNumber2)
{
OutputData <- list()
OutputData[[1]] <- rbind.fill(ListNumber1[[1]], ListNumber2[[1]])
OutputData[[2]] <- rbind.fill(ListNumber1[[2]], ListNumber2[[2]])
return(OutputData)
}
I want to improve this function introducing the possibility to use a variable number of arguments (i.e. lists in my example). Here is an attempt to do this but I don't see how to fill the arguments of rbind.fill().
ExampleFunctionUpgrade <- function(...)
{
Arguments <- list(...)
OutputData <- list()
VarNames <- paste0("List", seq_along(Arguments))
for (i in 1:length(Arguments))
{
assign(VarNames[i], Arguments[[i]])
}
OutputData <- rbind.fill(???)
return(OutputData)
}
I would try to iterate over the columns within an lapply call that is to be bound together.
ExampleFunctionUpgrade <- function(...)
{
Arguments <- list(...)
OutputData <- list()
for(i in 1:length(Arguments[[1]])) {
OutputData[[i]] <- rbind.fill(lapply(Arguments, '[[', i))
}
return(OutputData)
}
If you don't like 'for loops' you can use two lapply calls.

R Error Genetic Programming Implementation

So I am brand new to R. I started learning it yesterday, because there's some data that is being very resistant to automatically importing into Mathematica and Python. I'm building a few machine learning techniques to do analysis on the data that I can now import with R. This is a genetic programming implementation that when finished should do symbolic regression on some data. (I have yet to create the mutation or crossover operators, build a legit function list, etc). I get two errors when I run the script:
> Error: attempt to apply non-function
> print(bestDude)
> Error in print(bestDude) : object 'bestDude' not found
This is my code:
library("datasets")
#Allows me to map a name to each element in a numerical list.
makeStrName<-function(listOfItems)
{
for(i in 1:length(listOfItems))
{
names(listOfItems)[i]=paste("x",i,sep="")
}
return(listOfItems)
}
#Allows me to replace each random number in a vector with the corresponding
#function in a list of functions.
mapFuncList<-function(funcList,rndNumVector)
{
for(i in 1:length(funcList))
{
replace(rndNumVector, rndNumVector==i,funcList[[i]])
}
return(rndNumVector)
}
#Will generate a random function from the list of functions and a random sample.
generateOrganism<-function(inputLen,inputSeed, functions)
{
set.seed(inputSeed)
rnd<-sample(1:length(functions),inputLen,replace=T)
Org<-mapFuncList(functions,rnd)
return(Org)
}
#Will generate a series of "Organisms"
genPopulation<-function(popSize,initialSeed,initialSize,functions)
{
population<-list("null")
for(i in 2:popSize)
{
population <- c(population,generateOrganism(initialSize,initialSeed, functions))
initialSeed <- initialSeed+1
}
populationWithNames<-makeStrName(population)
return(populationWithNames)
}
#Turns the population of functions (which are actually strings in "") into
#actual functions. (i.e. changes the mode of the list from string to function).
populationFuncList<-function(Population)
{
Population[[1]]<-"x"
funCreator<-function(snippet)
txt=snippet
function(x)
{
exprs <- parse(text = txt)
eval(exprs)
}
listOfFunctions <- lapply(setNames(Population,names(Population)),function(x){funCreator(x)})
return(listOfFunctions)
}
#Applies a fitness function to the population. Puts the best organism in
#the hallOfFame.
evalPopulation<-function(populationFuncList, inputData,outputData)
{
#rmse <- sqrt( mean( (sim - obs)^2))
hallOfFame<-list(1000000000)
for(i in 1:length(populationFuncList))
{
total<-list()
for(z in 1:length(inputData))
{
total<-c(total,(abs(populationFuncList[[i]](inputData[[z]])-outputData[[z]])))
}
rmse<-sqrt(mean(total*total))
if(rmse<hallOfFame[[1]]) {hallOfFame[[1]]<-rmse}
}
return(hallOfFame)
}
#Function list, input data, output data (data to fit to)
funcs<-list("x","log(x)","sin(x)","cos(x)","tan(x)")
desiredFuncOutput<-list(1,2,3,4,5)
dataForInput<-list(1,2,3,4,5)
#Function calls
POpulation<-genPopulation(4,1,1,funcs)
POpulationFuncList<-populationFuncList(POpulation)
bestDude<-evalPopulation(POpulationFuncList,dataForInput,desiredFuncOutput)
print(bestDude)
The code is now working thanks to Hack-R's suggestions. So here's the finalized code in case someone else runs into a similar trouble.
library("datasets")
#Allows me to map a name to each element in a numerical list.
makeStrName<-function(listOfItems)
{
for(i in 1:length(listOfItems))
{
names(listOfItems)[i]=paste("x",i,sep="")
}
return(listOfItems)
}
#Allows me to replace each random number in a vector with the corresponding
#function in a list of functions.
mapFuncList<-function(funcList,rndNumVector)
{
for(i in 1:length(funcList))
{
rndNumVector[rndNumVector==i]<-funcList[i]
}
return(rndNumVector)
}
#Will generate a random function from the list of functions and a random sample.
generateOrganism<-function(inputLen,inputSeed, functions)
{
set.seed(inputSeed)
rnd<-sample(1:length(functions),inputLen,replace=T)
Org<-mapFuncList(functions,rnd)
return(Org)
}
#Will generate a series of "Organisms"
genPopulation<-function(popSize,initialSeed,initialSize,functions)
{
population<-list()
for(i in 1:popSize)
{
population <- c(population,generateOrganism(initialSize,initialSeed,functions))
initialSeed <- initialSeed+1
}
populationWithNames<-makeStrName(population)
return(populationWithNames)
}
#Turns the population of functions (which are actually strings in "") into
#actual functions. (i.e. changes the mode of the list from string to function).
funCreator<-function(snippet)
{
txt=snippet
function(x)
{
exprs <- parse(text = txt)
eval(exprs)
}
}
#Applies a fitness function to the population. Puts the best organism in
#the hallOfFame.
evalPopulation<-function(populationFuncList, inputData,outputData)
{
#rmse <- sqrt( mean( (sim - obs)^2))
hallOfFame<-list(1000000000)
for(i in 1:length(populationFuncList))
{
total<-vector(mode="numeric",length=length(inputData))
for(z in 1:length(inputData))
{
total<-c(total,(abs(populationFuncList[[i]](inputData[[z]])-outputData[[z]])))
}
rmse<-sqrt(mean(total*total))
if(rmse<hallOfFame[[1]]) {hallOfFame[[1]]<-rmse}
}
return(hallOfFame)
}
#Function list, input data, output data (data to fit to)
funcs<-list("x","log(x)","sin(x)","cos(x)","tan(x)")
desiredFuncOutput<-list(1,2,3,4,5)
dataForInput<-list(1,2,3,4,5)
#Function calls
POpulation<-genPopulation(4,1,1,funcs)
POpulationFuncList <- lapply(setNames(POpulation,names(POpulation)),function(x){funCreator(x)})
bestDude<-evalPopulation(POpulationFuncList,dataForInput,desiredFuncOutput)
print(bestDude)
In your function evalPopulation you're attempting to apply populationFuncList[[i]] as if it were a function, but when you pass in the argument POpulationFuncList to replace the variable populationFuncList it's not a function, it's a list.
I'm not sure what you were trying to do, so I'm not sure which way you want to fix this. If you meant to use a function you should change the name of the object you're referencing to the function and remove it as an argument or at least pass a function in as an argument instead of the list.
OTOH if you meant to use the list POpulationFuncList then you just shouldn't be applying it as if it were a function instead of a list.
On a side note, this probably would be more apparent if you didn't give them such similar names.
Another potential problem is that you seem have non-numeric results in one of your lists:
> populationFuncList(POpulation)
$x1
[1] "x"
$x2
[1] 2
$x3
[1] 1
$x4
[1] 1
You can't take the absolute value of the character "x", so I just wanted to make sure you're aware of this.
A third problem is that you're doing math on a non-numeric data typed object called total. You need to either change the type to numeric or index it appropriately.
Now it's impossible for me to know exactly which of an infinite number of possibilities you should choose to fix this, because I don't know the details of your use case. However, here is one possible solution which you should be able to adapt to the specifics of the use case:
library("datasets")
#Allows me to map a name to each element in a numerical list.
makeStrName<-function(listOfItems)
{
for(i in 1:length(listOfItems))
{
names(listOfItems)[i]=paste("x",i,sep="")
}
return(listOfItems)
}
#Allows me to replace each random number in a vector with the corresponding
#function in a list of functions.
mapFuncList<-function(funcList,rndNumVector)
{
for(i in 1:length(funcList))
{
replace(rndNumVector, rndNumVector==i,funcList[[i]])
}
return(rndNumVector)
}
#Will generate a random function from the list of functions and a random sample.
generateOrganism<-function(inputLen,inputSeed, functions)
{
set.seed(inputSeed)
rnd<-sample(1:length(functions),inputLen,replace=T)
Org<-mapFuncList(functions,rnd)
return(Org)
}
#Will generate a series of "Organisms"
genPopulation<-function(popSize,initialSeed,initialSize,functions)
{
population<-list("null")
for(i in 2:popSize)
{
population <- c(population,generateOrganism(initialSize,initialSeed, functions))
initialSeed <- initialSeed+1
}
populationWithNames<-makeStrName(population)
return(populationWithNames)
}
#Turns the population of functions (which are actually strings in "") into
#actual functions. (i.e. changes the mode of the list from string to function).
populationFuncList<-function(Population)
{
Population[[1]]<-"x"
funCreator<-function(snippet)
txt=snippet
function(x)
{
exprs <- parse(text = txt)
eval(exprs)
}
listOfFunctions <- lapply(setNames(Population,names(Population)),function(x){funCreator(x)})
return(listOfFunctions)
}
#Applies a fitness function to the population. Puts the best organism in
#the hallOfFame.
evalPopulation<-function(myList=myList, dataForInput,desiredFuncOutput)
{
#rmse <- sqrt( mean( (sim - obs)^2))
hallOfFame<-list(1000000000)
for(i in 1:length(populationFuncList))
{
total<-0
for(z in 1:length(dataForInput))
{
total<-c(total,(abs(myList[[i]]+(dataForInput[[z]])-desiredFuncOutput[[z]])))
}
rmse<-sqrt(mean(total*total))
if(rmse<hallOfFame[[1]]) {hallOfFame[[1]]<-rmse}
}
return(hallOfFame)
}
#Function list, input data, output data (data to fit to)
funcs<-list("x","log(x)","sin(x)","cos(x)","tan(x)")
desiredFuncOutput<-list(1,2,3,4,5)
dataForInput<-list(1,2,3,4,5)
#Function calls
POpulation<-genPopulation(4,1,1,funcs)
myList <-populationFuncList(POpulation)[2:4]
bestDude<-evalPopulation(myList,dataForInput,desiredFuncOutput)
print(bestDude)
[[1]]
[1] 1.825742

R programming: save three dimensional outputs after loop

I am new to R and I would like to save the out puts after the loop
for (i in 1:5) {
for (d in 1:10) {
fonction1
fonction2
fonction3
}
}
At the end I would like to have 1 list-> contains 5 list-> contains 1*10 data frame -> contains certain number*3 numeric data. (I dont know if im saying it correctly, what i want to have is: like in Matlab, there is a 1*5 structure -> contains five 1*10 structure -> contain certain number*3 numeric data).
thanks in advance
Looks like you are looking after something like the following:
out <- list()
for (i in 1:5) {
outList <- list()
for (d in 1:10) {
outVect <- c()
outVect[1] <- fonction1()
outVect[2] <- fonction2()
outVect[3] <- fonction3()
outList[[d]] <- outVect
}
out[[i]] <- outList
}
Then you can look at:
str(out)
to see the structure of your answer
Try this:
lst <- lapply(1:5, function(i) {
lapply(1:10, function(d) {
data.frame(function1(),
function2(),
function3())
})
})
Assuming function1, function2 and function3 all return equal-length vectors, the above code should produce your desired object. You can use i and d identically as you would have used them in your for loop code.

Resources