  We present a numerical model for determining a finite Blaschke product of
degree $n+1$ having $n$ preassigned distinct critical points $z_1,\dots,z_n$ in
the complex (open) unit disk $\mathbb{D}$. The Blaschke product is uniquely
determined up to postcomposition with conformal automorphisms of $\mathbb{D}$.
The proposed method is based on the construction of a sparse nonlinear system
where the data dependency is isolated to two vectors and on a certain
transformation of the critical points. The efficiency and accuracy of the
method is illustrated in several examples.
