------- Comment #21 from fxcoudert at gcc dot gnu dot org 2007-10-17 22:32 ------- I've been thinking about MINVAL((/NaN,NaN/)), ie minval of an array containing only NaNs, over and over again, and it's a tough choice. Here's what compilers currently output for MINVAL and MAXVAL:
Intel: Inf, -Inf Sun: -NaN, -NaN (yes, that's a negative NaN; don't ask) g95: Huge, -Huge gfortran: Huge, -Huge portland: NaN, -Huge MIPSpro: Inf, NaN IBM: Huge, -Huge So: we can take portland and MIPSpro out, they lack consistency; Intel goes for infinities, and I don't see how they can justify this in any way, so let's take them out also. The only two options worth considering are NaN (as Sun does) and Huge (as Intel and g95 do). Both have pros and cons. The main pro for NaN is that it ensures that MAXVAL((/x,x/)) is always equal to MAX(x,x), even when x is a NaN. The main pro for Huge is that it is more consistent with the way NaN are ignored: for all other purposes, NaNs in the array are handled as if the mask for that element was .false., so why single out the "only NaNs" case? Since different compilers already give different answers for this problem, I guess we can pick the solution we're most comfortable with. Unless people feel strongly against it, I'd like to go with Huge, because 1. I'm more convinced by arguments in favour of it, and 2. it's probably easier/faster/more efficient to implement, because it doesn't need yet another special case. Opinions welcome. (What a long rant.) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30694
