>>>>> Kun Ren

>>>>> on Sat, 19 May 2018 08:17:37 +0000 writes:

> Dear maintainers,

> I'm reporting a bug in qr.coef that mishandles the colnames of matrix. A minimal reproducible example is as follows:

> x <- cbind(rep(0, 10), rep(0, 10))

> y <- rep(0, 10)

> q <- qr.default(x)

> qr.coef(q, y)

> [1] NA NA

> If x has colnames, then qr.coef will end up with an error:

> x <- cbind(x1 = rep(0, 10), x2 = rep(0, 10))

> y <- rep(0, 10)

> q <- qr.default(x)

> qr.coef(q, y)

> Error in qr.coef(q, y) : object 'pivotted' not found

> This happens only when x any y are all zeros. I found this problem when I implement a qr-based wls which stops when all weights are zero and the x matrix has colnames.

> A brief debug on qr.coef shows that when `nam` is not NULL, no branch of code leads to creating `pivotted` before using it finally.

Dear Kun,

this is indeed a bug, and I will address it.

Thank you very much for the reprex (:= [repr]oducible [ex]ample)!

Best,

Martin Maechler

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