  Overlap coincidence in a self-affine tiling in $\R^d$ is equivalent to pure
point dynamical spectrum of the tiling dynamical system. We interpret the
overlap coincidence in the setting of substitution Delone set in $\R^d$ and
find an efficient algorithm to check the pure point dynamical spectrum. This
algorithm is easy to implement into a computer program. We give the program and
apply it to several examples. In the course the proof of the algorithm, we show
a variant of the conjecture of Urba\'nski (Solomyak \cite{Solomyak:08}) on the
Hausdorff dimension of the boundaries of fractal tiles.
