Re: [Rd] Bug in model.matrix.default for higher-order interaction encoding when specific model terms are missing

2017-11-06 Thread Arie ten Cate
Hello Tyler, model.matrix(~(X1+X2+X3)^3-X1:X3) T_i = X1:X2:X3. Let F_j = X3. (The numerical variables X1 and X2 are not encoded at all. Then, again, T_{i(j)} = X1:X2, which in this example is NOT dropped from the model. Hence the X3 in T_i must be encoded by contrast, as indeed it is. Arie On

Re: [Rd] Bug in model.matrix.default for higher-order interaction encoding when specific model terms are missing

2017-11-06 Thread Tyler
Hi Arie, Given the heuristic, in all of my examples with a missing two-factor interaction the three-factor interaction should be coded with dummy variables. In reality, it is encoded by dummy variables only when the numeric:numeric interaction is missing, and by contrasts for the other two. The he

Re: [Rd] ans[nas] <- NA in 'ifelse' (was: ifelse() woes ... can we agree on a ifelse2() ?)

2017-11-06 Thread Martin Maechler
> Suharto Anggono Suharto Anggono > on Sat, 4 Nov 2017 12:11:48 + writes: > Removal of > ans[nas] <- NA > from the code of function 'ifelse' in R is not committed (yet). Why? because I have been using it in my version of R-devel for this whole year, but have forgotten

Re: [Rd] Bug in model.matrix.default for higher-order interaction encoding when specific model terms are missing

2017-11-06 Thread Arie ten Cate
Hello Tyler, You write that you understand what I am saying. However, I am now at loss about what exactly is the problem with the behavior of R. Here is a script which reproduces your experiments with three variables (excluding the full model): m=expand.grid(X1=c(1,-1),X2=c(1,-1),X3=c("A","B","C

Re: [Rd] Extreme bunching of random values from runif with Mersenne-Twister seed

2017-11-06 Thread Duncan Murdoch
On 05/11/2017 10:58 AM, peter dalgaard wrote: On 5 Nov 2017, at 15:17 , Duncan Murdoch wrote: On 04/11/2017 10:20 PM, Daniel Nordlund wrote: Tirthankar, "random number generators" do not produce random numbers. Any given generator produces a fixed sequence of numbers that appear to meet var

Re: [Rd] Extreme bunching of random values from runif with Mersenne-Twister seed

2017-11-06 Thread Serguei Sokol
Le 05/11/2017 à 15:17, Duncan Murdoch a écrit : On 04/11/2017 10:20 PM, Daniel Nordlund wrote: Tirthankar, "random number generators" do not produce random numbers.  Any given generator produces a fixed sequence of numbers that appear to meet various tests of randomness.  By picking a seed you