Constrained Least Squares and Generalized QR Factorization R package LSE version 1.0.0 The solution of equality constrained least squares problem (LSE) is given through four analytics methods (Generalized QR Factorization, Lagrange Multipliers, Direct Elimination and Null Space method). We expose the orthogonal decomposition called Generalized QR Factorization (GQR) and also RQ factorization. Finally some codes for the solution of LSE applied in quaternions. Software Imports: MASS, pracma Sergio Andrés Cabrera Miranda <sergio05acm@gmail.com> Comprehensive R Archive Network (CRAN) Sergio Andrés Cabrera Miranda <https://orcid.org/0000-0002-8126-8521>, Juan Gabriel Triana Laverde <https://orcid.org/0000-0003-2991-6082> GPL-3 2022-02-02 application/tgz https://CRAN.R-project.org/package=LSE doi:10.32614/CRAN.package.LSE