# Solution of underdetermined systems using LAPACK

**URL:** <https://discourse.julialang.org/t/solution-of-underdetermined-systems-using-lapack/33000>\
**Category:** Performance\
**Created:** [January 5, 2020, 5:38pm UTC](https://discourse.julialang.org/t/solution-of-underdetermined-systems-using-lapack/33000 "2020-01-05T17:38:47Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![lucas711642](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lucas711642/32/12051_2.png) [@lucas711642](https://discourse.julialang.org/u/lucas711642)\
**Post date:** [January 10, 2020, 10:45pm UTC](https://discourse.julialang.org/t/solution-of-underdetermined-systems-using-lapack/33000/6 "2020-01-10T22:45:20Z")

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I was looking for a solution that minimizes memory allocation because I’m solving several systems in a loop. Since my systems have full rank, the cheaper LQ factorization can achieve the same result as pivoted QR.

I was wondering if there is any function available which can use the LQ factorization itself, without constructing the L and Q matrices explicitly.

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