Three iteratively reweighted least squares algorithms for L₁ -norm principal component analysis

Principal component analysis (PCA) is often used to reduce the dimension of data by selecting a few orthonormal vectors that explain most of the variance structure of the data. L₁ PCA uses the L₁ norm to measure error, whereas the conventional PCA uses the L₂ norm. For the L₁ PCA problem minimizing the fitting error of the reconstructed data, we propose three algorithms based on iteratively reweighted least squares. We first develop an exact reweighted algorithm. Next, an approximate version is developed based on eigenpair approximation when the algorithm is near convergent. Finally, the approximate version is extended based on stochastic singular value decomposition. We provide convergence analyses, and compare their performance against benchmark algorithms in the literature. The computational experiment shows that the proposed algorithms consistently perform the best and the scalability is improved as we use eigenpair approximation and stochastic singular value decomposition.