# Missing methods qr(A)' and qr(A') for sparse

**URL:** https://discourse.julialang.org/t/missing-methods-qr-a-and-qr-a-for-sparse/66370
**Category:** General Usage
**Tags:** linearalgebra, sparse
**Created:** [August 13, 2021, 11:02pm UTC](https://discourse.julialang.org/t/missing-methods-qr-a-and-qr-a-for-sparse/66370 "2021-08-13T23:02:40Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Thomas](https://avatars.discourse-cdn.com/v4/letter/t/e36b37/32.png) [@Thomas](https://discourse.julialang.org/u/Thomas)
#### Post date: [August 13, 2021, 11:02pm UTC](https://discourse.julialang.org/t/missing-methods-qr-a-and-qr-a-for-sparse/66370/1 "2021-08-13T23:02:41Z")

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Weird, that `Base.runtests("LinearAlgebra/qr")` passed, but I got this error (which I thought this has been fixed in [https://github.com/JuliaLang/SuiteSparse.jl/issues/22](https://github.com/JuliaLang/SuiteSparse.jl/issues/22))

```julia
using LinearAlgebra, SparseArrays
A = sprand(10,100,0.1);

qr(A)'
ERROR: MethodError: no method matching adjoint(::SuiteSparse.SPQR.QRSparse{Float64,Int64})

qr(A')
ERROR: MethodError: no method matching qr!(::SparseMatrixCSC{Float64,Int64})

```

```julia
Julia Version 1.6.2
Commit 1b93d53fc4 (2021-07-14 15:36 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin18.7.0)
  CPU: Intel(R) Core(TM) i7-8557U CPU @ 1.70GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-11.0.1 (ORCJIT, skylake)
Environment:
  JULIA_EDITOR = atom -a
  JULIA_NUM_THREADS = 4

```

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<div class="post-metadata">

### Author: ![Oscar\_Smith](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oscar_smith/32/25343_2.png) [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [August 14, 2021, 1:36am UTC](https://discourse.julialang.org/t/missing-methods-qr-a-and-qr-a-for-sparse/66370/2 "2021-08-14T01:36:24Z")

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I don’t think we is defined for sparse since q will be dense.