Displaying 7 results from an estimated 7 matches for "alexandri".
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alexandre
2010 Mar 11
3
Define column names to a series of data.frames
Greets to the list!
I am aware that this topic has been discussed several times. And I've
read quite some related posts [1]. Yet, can't seem to give a solution to
my problem.
I have 6 data frames consisting of 6 rows x 7 columns put together from
other data.frames.
Something like:
a b c d e f g
v1 # # # # # # #
v2 # # # # # # #
v3 # # # # # # #
v4 # # # # # # #
v5 # # # # # # #
v6
2010 Apr 21
1
Cross-checking a custom function for separability indices
...Divergence: 1.5658
Bhattacharryya: 0.1683
Jeffries-Matusita: 0.3098
Transformed divergence: 0.3555
Thanks in advance, Nikos
# --- Code -------------------------------------------------------------------
# Custom function for various Separability Measures
# by Nikos Alexandris, Freiburg, 8.04.2010
# ( based on Divergence and Jeffries-Matusita, requires input variables
"as.matrices" )
separability.measures <- function ( Vector.1 , Vector.2 ) {
# convert vectors to matrices in case they are not
Matrix.1 <- as.matrix (Vector.1)
Matrix.2 <...
2010 Dec 22
3
Estimate "between-axes" vs "within-axes heterogeneity of multivariate matrices
Hi!
My question(s) in the end might be silly but I am no expert on this, so here
it goes:
Noy-Meir (1973), Pielou (1984) and a few others have pointed to non-centered
PCA being in some cases useful. They clearly explain that "it is the case"
when multi-dimensional data display distinct clusters (which have zero, or
near-zero, projections in some subset of the axes) and the task is
2010 May 15
2
Attempt to customise the "plotpc()" function
Dear R-list,
Among the (R-)tools, I've seen on the net, for (bivariate) Principal Component
scatter plots (+histograms), "plotpc" [1] is the one I like most.
By default it performs PCA on a bivariate dataset based on R's "princomp()"
(which is the eigenvector-based algebraic solution to PCA). I would like to
modify "plotpc()" in order be able, as an
2009 May 23
1
create vectors within a double loop
Hi R-list.
This is my first post. I'll try to be as precise as possible with the
difficulty I have to "get things done".
I have a hard time trying to construct a double "for" loop and create
within the inner loop new objects (in this case vectors).
I posted this question in a non-directly related with pure R-problems
list (in grass-stats). In addition, I think I
2011 Sep 15
1
Creando scrips en R
...a(Mapa.v)] ### Elimino datos nulos del vector
SP1 <- sample(Mapa.vn, 50) ### Extraigo una muestra de 50 datos.
El asunto ahí no termina, después de realizar esas operaciones necesito calcular las "medidas de separabilidad" mediante el paquete(o script) separability.measures de Nikos Alexandris. La operación consiste en realizar comparaciones de pares para ese conjunto de 18 muestras (SPn). La #operación base es la siguiente:
#operación base
separability.measures (SP1,SP2) -> SP1ySP2
separability.measures (SP1,SP3) -> SP1ySP3
?
separability.measures (SP2,SP3) -> SP2ySP3
separa...
2010 May 05
0
R-help Digest, Vol 87, Issue 5
...igenvectors (Gabor Grothendieck)
109. Re: Visualizing binary response data? (Thomas Stewart)
110. Re: Visualizing binary response data? (Frank E Harrell Jr)
111. Re: readLines with space-delimiter? (jim holtman)
112. Re: Cross-checking a custom function for separability
indices (Nikos Alexandris)
113. Re: Symbolic eigenvalues and eigenvectors (Steve Lianoglou)
114. Re: Delete rows with duplicate field... (kMan)
115. converting an objects list (Anthony Fristachi)
116. masking of objects between mtrace() and getYahooData() (zerdna)
117. Re: How to make predictions with the predic...