JuliaLang/julia — pull request #4565 by andreasnoackjensen (2013-10-18 11:41:51+00:00)
Title: Change default qr subroutine to one that allows m<n. Update documentation for fat QR. Return permutation vector instead of matrix in pivoted QR.

This should address the issues in #4555, so now
```
julia> A=randn(2,4)
2x4 Array{Float64,2}:
1.14841 0.148657 0.50509 0.870583
0.5955 1.78331 -0.352758 -1.95542

julia> qr(A)
(
2x2 Array{Float64,2}:
-0.887745 -0.460335
-0.460335 0.887745,

2x4 Array{Float64,2}:
-1.29362 -0.952887 -0.286004 0.127291
0.0 1.51469 -0.54567 -2.13667 )
```

@dmbates I browsed through the GLM code and couldn't find any call directly to `geqrt3` anymore. If I have missed it, this pull request might affect GLM because I have changed `qrfact` to call `geqrt`. They are very similar as `geqrt` is just a higher level interface to `geqrt3`.