search for: cruadam

Hi, I have a big matrix X with M rows and N columns that I want to filter it into smaller ones with m (<M) rows and N columns. The filter rule is based on the values of each columns, i.e. X looks like this: column name: a, b, c, d, ... etc a b c d ... 1 2 3 4 ... 5 6 7 8 ... 9 8 7 6 ... ... ... ... ... The filter rule with the result that I want is:

Hi, I have an object, Z: > typeof(Z) [1] "list" It looks like: [,1] [,2] [,3] [1,] 1 1 1 [2,] 1 1 1 How can it label the Rows and Columns with Text? so that it looks like: Y1 Y2 Y3 X1 1 1 1 X2 1 1 1 Thanks, cruz

Hi, I am writing this in a wrong way, can someone please correct me? > A <- matrix() > length(A) <- 6 > dim(A) <- c(3,2) > colnames(A) <- c("X","Y") > A X Y [1,] NA NA [2,] NA NA [3,] NA NA > A$X Error in A$X : $ operator is invalid for atomic vectors > Thanks, cruz

Hi, How do we get the value of a chi square as we usually look up on the table on our text book? i.e. Chi-square(0.01, df=8), the text book table gives 20.090 > dchisq(0.01, df=8) [1] 1.036471e-08 > pchisq(0.01, df=8) [1] 2.593772e-11 > qchisq(0.01, df=8) [1] 1.646497 > nono of them give me 20.090 Thanks, cruz

Hi, What formula is appropriate for calculating the estimate of variance from the parametric fit? I have a linear regression model i.e. lm(a~b) Thanks, cruz

Hi, I am residing in Taipei, Taiwan. My windows has English R (2.7.2) installed. I noticed that the CRAN mirror for Taipei is Taiwan (Taipeh), Is Taipeh a Deutsch or English name? Thanks, cruz

Hi, I have read ?loess help page and did some google on loess, however there are insufficient information on weighted variance. I am wondering that if any of you know of an example or document on weighted variance using loess (), especially for the cases when more than one explanatory variable is involved. Thanks a lot, cruz

Hi, Why the qr() produces a negative Q compared with Gram-Schmidt? (note example below, except Q[2,3]) Here is an example, I calculate the Q by Gram-Schmidt process and compare the output with qr.Q() a <- c(1,0,1) b <- c(1,0,0) c <- c(2,1,0) x <- matrix(c(a,b,c),3,3) ########################## # Gram-Schmidt ########################## A <- matrix(a,3,1) q1 <-

Hi, I compute the value of xi*xj by "for" loops, this how I try: > x1 <- c(1:3) > x2 <- c(2:4) ### to compute x1*x2 > (paste("x", 1, sep = ""))*(paste("x", 2, sep = "")) Error in (paste("x", 1, sep = "")) * (paste("x", 2, sep = "")) : non-numeric argument to binary operator > All