Displaying 20 results from an estimated 4000 matches similar to: "Cluster analysis with missing data"
2009 Nov 10
2
All possible combinations of functions within a function
Dear All,
I wrote a function for cluster analysis to compute cophenetic correlations
between dissimilarity matrices (using the VEGAN library) and cluster
analyses of every possible clustering algorithm (SEE ATTACHED)
http://old.nabble.com/file/p26288610/cor.coef.R cor.coef.R . As it is now,
it is extremely long, and for the future I was hoping to find a more
efficient way of doing this sort of
2011 Sep 09
2
NMDS plot and Adonis (PerMANOVA) of community composition with presence absence and relative intensity
Hi!
Thanks for providing great help in R-related statistics. Now, however I'm
stuck. I'm not a statistics person but I was recommended to use R to perform
a nmds plot and PerMANOVA of my dataset.
Sample(treatment) in the columns and species (OTU) in the rows. I have 4
treatments (Ambient Temperature, Ambient temperature+Low pH, High
temperature, High temperature+low pH), and I have 16
2010 Feb 02
2
hvcluster() with distance method from vegdist(), package = vegan
hello,
i'd be happy if someone could provide help with the following problem:
i have a dist.matrix that comes from vegdist() function of the vegan
package. the used method = "horn" is not accepted as argument in
hvcluster(...,dist.method="...").
is there a way to incorporate the method "horn" in hvcluster()?
thanks in advance!
yours,
kay
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2009 Oct 14
2
metaMDS NMDS: use of alternative distances?
Dear r-helpers!
How can I integrate other distances (in the form of a dist object) into function metaMDS? The problem: metaMDS needs the original data.frame for the calculation and only the default distances of function vegdist are allowed.
Any suggestions are greatly appreciated!
Thank you,
Kim
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2011 May 17
1
simprof test using jaccard distance
Dear All,
I would like to use the simprof function (clustsig package) but the available distances do not include Jaccard distance, which is the most appropriate for pres/abs community data. Here is the core of the function:
> simprof
function (data, num.expected = 1000, num.simulated = 999, method.cluster = "average",
method.distance = "euclidean", method.transform =
2013 Jul 23
1
Heat Map for species - code from Numerical Ecology with R
Hello, I am relatively new to R and I am working through the code that is provided in the book Numerical Ecology with R and I have run across an error message that I can't seem to figure out. I am using the vegan, ade4, gclus and cluster packages. The code is as follows: # Ordered community table # Species are ordered by their weighted averages on site scores or <- vegemite(spe,
2006 Jan 17
1
Clustering function
Dear mailing group,
I have loaded an Excel file into R by calling it ".csv" and using the
"read.csv" function in R. However then I want to use the (limma package
specific, I believe) function "hclust", which clusters data in a tree
dendrogram, by similarity. However, I receive the errors msg.s: 1) "missing
observations in cov/cor" 2) "In
2006 Nov 17
3
gower distance calculation
Hello
I have 2 rows in a matrix and I want to calculate the Gower Distance between
the 2 , how can I do it?
I searched and found nothing that can help me, and my program doesn't know
the gdist function and I couldn't find it on the R help site.
Can anyone help me plz
Thank u all
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2008 May 15
1
metaMDS using Dissimilarity matrix
Hello R-user community!
I am running R 2.7.0 on a Power Book (Tiger). (I am still R and
statistics beginner)
Presently I try to run the function metaMDS (vegan) using an existing
dissimilarity-matrix.
As I would like to start with this matrix I thought I could just give
the matrix using the x= -argument
Test<-metaMDS(x=Dist.Gower)
Fehler in inherits(comm, "dist") :
2004 Apr 12
1
question on isoMDS
Hello everyone,
I have a question on isoMDS.
My data set (of vegetation) with 210 samples is in this way:
Rotfoehrenau Lavendelweidenau Silberweidenau ....
067_Breg.7 0 2 0 ....
071_Dona.4 0 2 6 ....
...
I want to do an isoMDS-analysis with the dissimilarity index
2004 May 13
2
BIO-ENV procedure
I've been unable to find a R package that provides the means of
performing Clarke & Ainsworth's BIO-ENV procedure or something
comparable. Briefly, they describe a method for comparing two separate
sample ordinations, one from species data and the second from
environmental data. The analysis includes selection of the 'best'
subset of environmental variables for explaining
2012 Oct 11
2
extracting groups from hclust() for a very large matrix
Hello,
I'm having trouble figuring out how to see resulting groups (clusters)
from my hclust() output. I have a very large matrix of 4371 plots and 29
species, so simply looking at the graph is impossible. There must be a
way to 'print' the results to a table that shows which plots were in
what group, correct?
I've attached the matrix I'm working with (the whole thing
2001 May 30
3
Transformation of dissimilarity or distance matrix
Dear List,
is there an elegant (or even not elegant) way how to transform
dissimilarity or distance matrix A
(or, in general, arbitrary symmetrical matrix) by transposition of rows and
columns into a form
closest to "block diagonal" matrix B?
The matrix A is adjusted the following way
A[A<epsilon] <-0 #(epsilon is given "small" number)
B: (in its ideal form)
2013 Apr 11
1
Ordination Plotting: Warning: Species scores not available
Hi,
I am working with a species-by-trait .csv file (columns=traits, rows=species) and get the following warning message when trying to plot results of both metaMDS and pcoa:
"Warning message:
In ordiplot(x, choices = choices, type = type, display = display, :
Species scores not available"
I am using a Gower's transformation in both procedures within the metaMDS or pcoa
2013 Dec 17
1
What is the formula of Pseudo-F statistic in capscale in vegan?
Dear R-help,
We are conducting a distance-based redundancy analysis using capscale and
then testing for statistical significance for six terms in the model for the
constrained ordination using anova.cca in the vegan package. The
significance test is sequential, i.e., testing for significance of a term
only after accounting for all preceding terms. Could someone please provide
us with either the
2010 Mar 16
1
memory failure in adonis function (permanova)
Dear all,
I am trying to get a PERMANOVA with quite large data set. I am reading a lot
about this question, but I do not get the answer about it. Although I know
that the R function is adonis () (vegan package), it does not work:
adonis(Pha.env~SPha, data=Pha, permutations=10)
The error message:
Error: cannot allocate vector of size 334.2 Mb
In addition: Warning messages:
1: In vegdist(lhs,
2018 Apr 17
2
nMDS with R: missing values
Dear All,
I was wondering whether anyone might be able to provide some advice with an nMDS / R problem. I?m trying to run nMDS on a dataset that contains many missing values and was wondering how I can account for the missing values when running nMDS? It seems as though the data are being grouped depending on where the zero values appear. Any suggestions greatly appreciated. Thank you very much
2011 Oct 03
4
distance coefficient for amatrix with ngative valus
Hi,
I need to run a PCoA (PCO) for a data set wich has both positive and negative values for variables. I could not find any distancecoefficient other than euclidean distace running for the data set. Are there any other coefficient works with negtive values.Also I cannot get summary out put (the eigen values) for PCO as for PCA.
Thanks.
Dilshan
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2004 Mar 16
2
bray-curtis?
Does R have a function to calculate Bray-Curtis distance measures, which is
probably one of the most frequently used and recommended dissimilarity
measures in ecology? It isn't mentioned in dist().
2011 Jan 27
3
agnes clustering and NAs
Hello,
In the documentation for agnes in the package 'cluster', it says that NAs are allowed, and sure enough it works for a small example like :
> m <- matrix(c(
1, 1, 1, 2,
1, NA, 1, 1,
1, 2, 2, 2), nrow = 3, byrow = TRUE)
> agnes(m)
Call: agnes(x = m)
Agglomerative coefficient: 0.1614168
Order of objects:
[1] 1 2 3
Height (summary):
Min. 1st Qu. Median Mean 3rd