Evaluating analog arithmetic circuit for approximate computing with DNA strand displacement

Approximate computing stands out in systems in which the simplicity must be above the demand for high precision and processing speed. It is the case of DNA systems, especially those based on the DNA strand displacement technique, which is naturally in a complex and noise-filled environment. In this sense, proposals for approximate DNA circuits implemented with an analog approach promise future disease diagnosis applications, for example. In this paper, we adapted a multiplication gate presented in the literature in order to reduce the influence of leak reactions. For this, we insert drain species after some time at the beginning of the process. Next, we built a DNA analog circuit using the multiplication gate with the extended addition and subtraction gates, proposed earlier, to solve a simple expression. The results showed that our modification significantly reduced the effects of leaks and the implemented circuit has an adequate accuracy with an acceptable error when their inputs species present median concentrations.