Displaying 20 results from an estimated 2000 matches similar to: "off-topic: affine transformation matrix"
2005 Dec 29
2
How to fit all points into plot?
Hi,
I have a problem when I want to add new points (or a
new line) to the graph. Some points (or parts of the
line) are not shown on the graph because they lie
beyond the scale of the axis. Is there a way to
overcome this so all points (or the entire line) are
shown on the graph? Here's an example of my problem:
colors = c("red", "blue")
plot(x=rnorm(100,0,1),
2010 Nov 09
2
Help with Iterator
Dear Experts,
The following is my "Iterator". When I try to write a new function with
itel, I got error.
This is what I have:
> supDist<-function(x,y) return(max(abs(x-y)))
>
> myIterator <- function(xinit,f,data=NULL,eps=1e-6,itmax=5,verbose=FALSE) {
+ xold<-xinit
+ itel<-0
+ repeat {
+ xnew<-f(xold,data)
+ if (verbose) {
+ cat(
+
2007 May 14
1
cross-validation / sensitivity anaylsis for logistic regression model
Hi,
I have developed a logistic regression model in the form of (factor_1~ numeric
+ factor_2) and would like to perform a cross-validation or some similar
form of sensitivity analysis on this model.
using cv.glm() from the boot package:
# dataframe from which model was built in 'z'
# model is called 'm_geo.lrm'
# as suggested in the man page for a binomial model:
cost <-
2012 Jul 02
0
Fit circle with R
Dear Researchers,
I wrote two function to fit a circle using noisy data.
1- the fitCircle() is derived from MATLAB code of * zhak Bucher* from the
link
http://www.mathworks.com/matlabcentral/fileexchange/5557-circle-fit/content/circfit.m
2- the CircleFitByPratt() from MATLAB code of *Nikolai Chernov *from the
link
2006 May 23
1
standardization of values before call to pam() or clara()
Greetings,
Experimenting with the cluster package, and am starting to scratch my head in
regards to the *best* way to standardize my data. Both functions can
pre-standardize columns in a dataframe. according to the manual:
Measurements are standardized for each variable (column), by subtracting the
variable's mean value and dividing by the variable's mean absolute deviation.
This
2007 Jul 22
1
Package design, placement of legacy functions
I have a function XOLD() from a nearly verbatim port of legacy
FORTRAN in a package. I have remplemented this function as XNEW()
using much cleaner native R and built-in functions of R. I have
switched the package to the XNEW(), but for historical reasons would
like to retain the XOLD() somewhere in the package directory
structure. An assertion through a README or other will point to
2006 Oct 04
2
compiling rgdal package on windows / macos
Greetings:
As I am not a windows user, I cannot try this: is it possible to install rgdal
on windows without having to compile it from source ?
Compilation on MacOS is within my abilities, however each time i try and
install the rgdal package it dies complaining that it cannot find
gdal-config --- which was recently installed with GRASS. I have updated my
PATH environment variable, logged
2008 Dec 05
3
Logical inconsistency
Dear colleagues
Please could someone kindly explain the following inconsistencies I've discovered when performing logical calculations in R:
8.8 - 7.8 > 1
> TRUE
8.3 - 7.3 > 1
> TRUE
Thank you,
Emma Jane
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2005 Nov 28
1
overlay additional axes
Greetings,
I am trying to add an extra labled axis in position 3 (top x-axis), with
numbers that do not match up with the existing axes.
Surely this must be possible, and I am just doing it incorectly.
So far I have tried the following:
#make a plot
plot(TIK, type="l", cex=.25, xlim=c(2,32), ylim=c(0,1600))
#try and add a new axis with different numbers in position 3
2006 Apr 10
2
passing known medoids to clara() in the cluster package
Greetings,
I have had good success using the clara() function to perform a simple cluster
analysis on a large dataset (1 million+ records with 9 variables).
Since the clara function is a wrapper to pam(), which will accept known medoid
data - I am wondering if this too is possible with clara() ... The
documentation does not suggest that this is possible.
Essentially I am trying to
2006 Oct 25
1
any good way to convert sp class objects to splancs object
Greetings:
are there any simple ways to convert an sp class object to a splancs ppp class
object, outside of reading the coordinates and computing a bounding box?
cheers,
--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341
2007 Feb 14
1
model diagnostics for logistic regression
Greetings,
I am using both the lrm() {Design} and glm( , family=binomial()) to perform a
a logisitic regression in R. Apart from the typical summary() methods, what
other methods of diagnosing logistic regression models does R provide? i.e.
plotting an 'lm' object, etc.
Secondly, is there any facility to calculate the R^{2)_{L} as suggested by
Menard in "Applied Logistic
2007 Feb 27
1
prop.test or chisq.test ..?
Hi everyone,
Suppose I have a count the occurrences of positive results, and the total
number of occurrences:
pos <- 14
total <- 15
testing that the proportion of positive occurrences is greater than 0.5 gives
a p-value and confidence interval:
prop.test( pos, total, p=0.5, alternative='greater')
1-sample proportions test with continuity correction
data: 14 out of
2006 Sep 20
2
mysterious error on compile R 2.3.1
Getting a very strange error with a new install of R from source on x86;
make[3]: Leaving directory `/tmp/R.INSTALL.r20887/cluster/src'
** R
** data
** moving datasets to lazyload DB
Error in factor(c(1, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1), :
invalid labels; length 2 should be 1 or 1
Execution halted
ERROR: lazydata failed for package 'cluster'
** Removing
2010 Oct 06
2
A problem --thank you
dear:teacher
i have a problem which about the polr()(package "MASS"), if the response must have 3 or more levels?
and how to fit the polr() to 2 levels?
thank you.
turly yours
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2006 Nov 07
0
evaluation of 2 matrices: categorical comparison
Greetings,
I have two matrices, read in from raster data stored in GRASS. Each matrix
represents the output of a aggregation process on categorical data (Nomial /
Ordinal) - derived from imagery.
I have compared these two data by the following methods:
***** pretending the data is continuous approaches (flawed i am sure...)
1. computing a difference map by computing the absolute difference
2005 Feb 13
2
row equality.
I think that this is an easy one...
I have a matrix where each row is an (x,y,z) triplet. Given a potential
(xnew,ynew,znew) triplet I want to know if the matrix already contains a
row with the new values (the space already has that point). I can do it
using a for loop, but I would like to know if there is anyway in which I
can do it without the for loop.
I do it now like this (this
2006 Mar 02
1
extracting RGB values from a colorspace class object
Greetings,
After pouring over the documentation for the 'colorspace' package, I have not
been able to figure out how the plot() method converts colorspace coordinates
to RGB values for display on the screen. I am convert between colorspaces
with the various as() methods... but cannot seem to find a way to extract RGB
(i.e. for displaying on a computer screen) triplets from color space
2011 Jun 14
2
Need script to create new waypoint
Dear help-list members,
I am a student at Durham University (UK) conducting a PhD on spatial representation in baboons. Currently, I'm analysing the effect of sampling interval on home range calculations.
I have followed the baboons for 234 days in the field, each day is represented by about 1000 waypoints (x,y coordinates) recorded at irregular time intervals. Consecutive waypoints in
2009 Aug 31
1
clarificatin on validate.ols method='cross'
Hi,
I was hoping to clarify the exact behavior associated with this incantation:
validate(fit.ols, method='cross', B=50)
Output:
index.orig training test optimism index.corrected n
R-square 0.5612 0.5613 0.5171 0.0442 0.5170 50
MSE 1.3090 1.3086 1.3547 -0.0462 1.3552 50
Intercept 0.0000 0.0000 -0.0040 0.0040