I am using vegan::rarecurve on community data.
lac.com.data<-wisconsin(lac.com.data)
rarecurve(lac.com.data)
Unfortunately, I am getting an error and cannot figure out how to fix it.
Error in seq.default(1, tot[i], by = step) : wrong sign in 'by' argument
I tried
rarecurve(lac.com.data,step=1)
to no avail.
I already generated a tabasco() graph and performed a Wisconsin standardization on the data frame without any problem.
There is no reproducible example. However, your usage is wrong. Function rarecurve needs input data of counts: it samples individuals from each sampling unit (row), and therefore you must have data on individuals. The error is caused by the use of wisconsin(lac.com.data): after that all rowSums(lac.com.data) will be 1, and your data are non-integers. You cannot use rarecurve for wisconsin() transformed data or any other non-integer data. Here the error manifests because the estimated numbers of individuals (rowSums of transformed data which are all 1) are lower than the number of species (>1).
Obviously we need to check input in rarecurve. We assumed that people would know what kind input is needed, but we were wrong.
Related
I'm trying to use the function variance_ratio() from the 'codyn' package to find whether two populations' abundances are positively or negatively correlated over time. The column I'm using for species.var isn't actually the species names; it's names for the two populations. For replicate.var, I am using a variable called "siteyear."
When I try to find the variance ratio, I'm getting the error message
"Error in check_multispp(df, species.var, replicate.var): One or more replicates consists of only a single species; please remove these replicates prior to calculations."
I assume this error means that one of the "species" is not found at all in some of the replicates, making its abundance always zero. However, I checked and all the site-years have abundance >0 for both "species", for at least one time point. There are some time points where one population has 0 abundance, but I don't see why that should be an issue.
In trying to create minimal sample data that would replicate the error, I managed to figure out the cause. There were some replicates in my data frame with only one value for time.var (the time series had just one time point). This was flagged by the function check_multispp(), which is supposed to check whether the time series has more than one species, but the error message was slightly misleading.
I am trying to create a person item map that organizes the questions from a dataset in order of difficulty. I am using the eRm package and the output should looks like follows:
[person-item map] (https://hansjoerg.me/post/2018-04-23-rasch-in-r-tutorial_files/figure-html/unnamed-chunk-3-1.png)
So one of the previous steps, before running the function that outputs the map, I have to fit the data set to have a matrix which is the object that the plotting functions uses to create the actual map, but I am having an error when creating that matrix
I have already tried to follow and review some documentation that might be useful if you want to have some extra-information:
[Tutorial] https://hansjoerg.me/2018/04/23/rasch-in-r-tutorial/#plots
[Ploting function] https://rdrr.io/rforge/eRm/man/plotPImap.html
[Documentation] https://eeecon.uibk.ac.at/psychoco/2010/slides/Hatzinger.pdf
Now, this is the code that I am using. First, I install and load the respective libraries and the data:
> library(eRm)
> library(ltm)
Loading required package: MASS
Loading required package: msm
Loading required package: polycor
> library(difR)
Then I fit the PCM and generate the object of class Rm and here is the error:
*the PCM function here is specific for polytomous data, if I use a different one the output says that I am not using a dichotomous dataset
> res <- PCM(my.data)
>Warning:
The following items have no 0-responses:
AUT_10_04 AUN_07_01 AUN_07_02 AUN_09_01 AUN_10_01 AUT_11_01 AUT_17_01
AUT_20_03 CRE_05_02 CRE_07_04 CRE_10_01 CRE_16_02 EFEC_03_07 EFEC_05
EFEC_09_02 EFEC_16_03 EVA_02_01 EVA_07_01 EVA_12_02 EVA_15_06 FLX_04_01
... [rest of items]
>Responses are shifted such that lowest
category is 0.
Warning:
The following items do not have responses on
each category:
EFEC_03_07 LC_07_03 LC_11_05
Estimation may not be feasible. Please check
data matrix
I must clarify that all the dataset has a range from 1 to 5. Is a Likert polytomous dataset
Finally, I try to use the plot function and it does not have any output, the system just keep loading ad-infinitum with no answer
>plotPImap(res, sorted=TRUE)
I would like to add the description of that particular function and the arguments:
>PCM(X, W, se = TRUE, sum0 = TRUE, etaStart)
#X
Input data matrix or data frame with item responses (starting from 0);
rows represent individuals, columns represent items. Missing values are
inserted as NA.
#W
Design matrix for the PCM. If omitted, the function will compute W
automatically.
#se
If TRUE, the standard errors are computed.
#sum0
If TRUE, the parameters are normed to sum-0 by specifying an appropriate
W.
If FALSE, the first parameter is restricted to 0.
#etaStart
A vector of starting values for the eta parameters can be specified. If
missing, the 0-vector is used.
I do not understand why is necessary to have a score beginning from 0, I think that that what the error is trying to say but I don't understand quite well that output.
I highly appreciate any hint that you can provide me
Feel free to ask for any information that could be useful to reach the solution to this issue
The problem is not caused by the fact that there are no items with 0-responses. The model automatically corrects this by centering the response scale categories on zero. (You'll notice that the PI-map that you linked to is centered on zero. Also, I believe the map you linked to is of dichotomous data. Polytomous data should include the scale categories on the PI-map, I believe.)
Without being able to see your data, it is impossible to know the exact cause though.
It may be that the model is not converging. That may be what this error was alluding to: Estimation may not be feasible. Please check data matrix. You could check by entering > res at the prompt. If the model was able to converge you should see something like:
Conditional log-likelihood: -2.23709
Number of iterations: 27
Number of parameters: 8
...
Does your data contain answers with decimal numbers? I found the same error, I solved it by using dplyr::dense_rank() function:
df_ranked <- sapply(df_decimal_data, dense_rank)
Worked.
I'm a total R beginner and try to cluster user data using the function skmeans.
I always get the error message:
"Error in if (!all(row_norms(x) > 0)) stop("Zero rows are not allowed.") :
missing value where TRUE/FALSE needed".
There already is a topic about this error message explaining that zeros are not allowed in rows.
However, my blueprint for what I'm trying to do is an example based on a data set which is also full of zeros. Working with this example, the error message does not appear and the function works fine. The error message only occurs when I apply the same procedure to my data set which doesn't seem different from the blueprint's data set.
Here's the function used for the kmeans:
weindaten.clusters <- skmeans(wendaten.tr, 5, method="genetic")
And here's the data set:
For my own data set, I used this function
kunden.cluster<- skmeans(test4, 5, method="genetic")
for this data set:
Could somebody please help me understand what the difference between the two data sets is (vector vs. something else maybe) and how I can change my data to be able to use skeams?
You cannot use spherical k-means on this data.
Spherical k-means uses angles for similarity. But the all-zero row cannot be used in angular computations.
Choose a different algorithm, unless you can treat the all-zero roe specially (for example on text, this would be an empty document).
Possibly it's a stupid question (but be patient, I'm a beginner in R's word)... I'm working with ImpulseDE2, a package designed to RNAseq data analysis along different times (see article for more information).
The running function (runImpulseDE2) requires a matrix counts and a annotation data frame. I've created both but it appears this error message:
Error in checkCounts(matCountData, "matCountData"): ERROR: matCountData contains non-integer elements. Requires count data.
I have tried some solutions and nothing seems to work (and I've not found any solution in the Internet)...
as.matrix(data)
(data + 1) > and there isn't NAs nor zero values that originate this error ($ which(is.na(data)) and $ which(data < 1), but both results are integer(0))
as.numeric(data) > and appears another error: ERROR: [Rownames of matCountData] was not given as input.
I think that's something I'm not realizing, but I'm totally locked. Every tip will be welcome!
And here is the (silly) solution! This function seems not to accept float numbers... so applying a simple round is enough to solve this error.
Thanks for your help!
I was trying to run some entropy() calculations on Force Platform data and i get a warning message:
> library(entropy)
> d2 <- read.csv("c:/users/SLA9DI/Documents/data2.csv")
> entropy(d2$CoPy, method="MM")
[1] 10.98084
> entropy(d2$CoPx, method="MM")
[1] 391.2395
Warning message:
In log(freqs) : NaNs produced
I am sure it is because the entropy() is trying to take the log of a negative number. I also know R can do complex numbers using complex(), however i have not been successful in getting it to work with my data. I did not get this error on my CoPy data, only the CoPx data, since a force platform gets Center of Pressure data in 2 dimensions. Does anyone have any suggestions on getting complex() to work on my data set or is there another function that would work better to try and get a proper entropy calculation? Entropy shouldn't be that much greater in CoPx compared to CoPy. I also tried it with some more data sets from other subjects and the same thing was popping up, CoPx entropy measures were giving me warning messages and CoPy measurements were not. I am attaching a data set link so anyone can try it out for themselves and see if they can figure it out, as the data is a little long to just post into here.
Data
Edit: Correct Answer
As suggested, i tried the table(...) function and received no warning/error message and the entropy output was also in the expected range as well. However, i apparently overlooked a function in the package discretize() and that is what you are supposed to use to correctly setup the data for entropy calculation.
I think there's no point in applying the entropy function on your data. According to ?entropy, it
estimates the Shannon entropy H of the random variable Y from the corresponding observed counts y
(emphasis mine). This means that you need to convert your data (which seems to be continuous) to count data first, for instance by binning it.