  Complex-valued neural networks (CVNNs) are nonlinear filters used in the
digital signal processing of complex-domain data. Compared with real-valued
neural networks~(RVNNs), CVNNs can directly handle complex-valued input and
output signals due to their complex domain parameters and activation functions.
With the trend toward low-power systems, computational complexity analysis has
become essential for measuring an algorithm's power consumption. Therefore,
this paper presents both the quantitative and asymptotic computational
complexities of CVNNs. This is a crucial tool in deciding which algorithm to
implement. The mathematical operations are described in terms of the number of
real-valued multiplications, as these are the most demanding operations. To
determine which CVNN can be implemented in a low-power system, quantitative
computational complexities can be used to accurately estimate the number of
floating-point operations. We have also investigated the computational
complexities of CVNNs discussed in some studies presented in the literature.
