GPU accelerated nonlinear optimization in radio interferometric calibration

We present the GPU based acceleration of two well known nonlinear optimization routines: Levenberg-Marquardt (LM) and Limited Memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) in radio interferometric calibration. Radio interferometric calibration is a heavily compute intensive operation where the same nonlinear optimization problem has to be solved over many time intervals, with different data. We achieve a speedup of about 3 times compared with conventional multi-core CPU based optimization by using GPU accelerated linear algebra routines (CULAtools,CUBLAS). We present details of our GPU accelerated optimization algorithms as well as timing comparisons with non-GPU based multi-core CPU routines.