OPM, a collection of Optimization Problems in Matlab S. Gratton and Ph. L. Toint December 2021 Abstract. OPM is a small collection of CUTEst unconstrained and bound-constrained nonlinear optimization problems, which can be used in Matlab for testing optimization algorithms directly (i.e. without installing additional software). Keywords: nonlinear optimization, test problems, Matlab, CUTEst.