From maechler@stat.math.ethz.ch  Fri Oct 19 16:15:42 2001
From: maechler@stat.math.ethz.ch (maechler@stat.math.ethz.ch)
Date: Fri, 19 Oct 2001 17:15:42 +0200 (MET DST)
Subject: [Rd] seq (PR#1133)
Message-ID: <200110191515.RAA23746@pubhealth.ku.dk>

>>>>> "Wst" == Werner Stahel <stahel@stat.math.ethz.ch> writes:

    Wst> In the following special case, seq fails to give the right answer
    Wst> (which is  0 )

    >> seq(0,0,1)
    Wst> Error in if (dd < sqrt(.Machine$double.eps)) return(from) : 
    Wst> missing value where logical needed

    .....

    Wst> The error occurs in the statement

    Wst>     dd <- abs(del)/max(abs(to), abs(from))

    Wst> of  seq.default  -- for obvious reasons. 
    Wst> This is certainly easy to debug...
yes
    Wst> Thank you for your efforts.

Thank you, Werner!

It's now fixed for R-devel; this is the patch I've used:

--- src/library/base/R/seq.R	16 Aug 2001 14:55:20 -0000	1.14
+++ src/library/base/R/seq.R	19 Oct 2001 14:44:43 -0000
@@ -19,7 +19,9 @@
 	if(missing(by))
 	    from:to
 	else { # dealing with 'by'
-	    n <- (del <- to - from)/by
+	    del <- to - from
+	    if(del == 0 && to == 0) return(to)
+	    n <- del/by
 	    if(!(length(n) && is.finite(n))) {
 		if(length(by) && by == 0 && length(del) && del == 0)
 		    return(from)


Martin

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[Rd] seq (PR#1133)
maechler@stat.math.ethz.ch