Journal of Computational Mathematics, Vol. 21, No. 2 (MARCH 2003), pp. 175-182 (8 pages) Least-squares solution of AX B = D with respect to symmetric positive semidefinite matrix X is considered. By ...

can be solved by solving an equivalent linear complementarity problem when H is positive semidefinite. The approach is outlined in the discussion of the LCP subroutine in Chapter 17, "Language ...

The higher-order accuracy of flat-top kernel estimators typically comes at the sacrifice of the positive semidefinite property. Nevertheless, we show how a flat-top estimator can be modified to become ...

We discuss in particular the case of quantum-state tomography, where the aim is to recover the density matrix, a positive semidefinite matrix, typically normalised with unit trace.