A symmetric matrix A is completely positive (CP) if there exists an
entrywise nonnegative matrix B such that A=BBT. We characterize the
interior of the CP cone. A semidefinite algorithm is proposed for checking
interiors of the CP cone, and its properties are studied. A CP-decomposition of
a matrix in Dickinson's form can be obtained if it is an interior of the CP
cone. Some computational experiments are also presented