https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/QR-factorisation-from-LAPACK/m-p/1011586#M19245 <P>Hi,</P> <P>I would like to do a QR factorization using LAPACK. From the documentation available here&nbsp;https://software.intel.com/en-us/node/521003#E832D468-0891-40EC-9468-6868C8EC9AD0 , I've decided to use geqrf &nbsp;for the factorization.</P> <P>As I need to solve a Least square problem, I need to solve R.x = (Q1)^T b as explained in the documentation. You can apply matrix Q with the function ormqr. But, which routine should I use to solve R.x = y ?</P> <P>&nbsp;</P> Thu, 03 Sep 2015 14:08:53 GMT velvia 2015-09-03T14:08:53Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/QR-factorisation-from-LAPACK/m-p/1011586#M19245 <P>Hi,</P> <P>I would like to do a QR factorization using LAPACK. From the documentation available here&nbsp;https://software.intel.com/en-us/node/521003#E832D468-0891-40EC-9468-6868C8EC9AD0 , I've decided to use geqrf &nbsp;for the factorization.</P> <P>As I need to solve a Least square problem, I need to solve R.x = (Q1)^T b as explained in the documentation. You can apply matrix Q with the function ormqr. But, which routine should I use to solve R.x = y ?</P> <P>&nbsp;</P> Thu, 03 Sep 2015 14:08:53 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/QR-factorisation-from-LAPACK/m-p/1011586#M19245 velvia 2015-09-03T14:08:53Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/QR-factorisation-from-LAPACK/m-p/1011587#M19246 <P>Velvia, can you explain what you are attempting to do? If all you want is the least-squares solution to overdetermined equations with a full-rank matrix, you can use the "driver" routine ?GELS().&nbsp;</P> Thu, 03 Sep 2015 21:46:41 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/QR-factorisation-from-LAPACK/m-p/1011587#M19246 mecej4 2015-09-03T21:46:41Z