We performed the benchmark calculations on a computing server equipped with 32-Core AMD EPYC 7542 Processor (providing 64 threads with multithreading) and with 128GB of memory. Figure 3 demonstrates a **data** sets obtained for the decomposition of the 4-qubit unitary labeled by adder-q4 taken from the benchmark examples of the QFAST package. The figure shows the results of 30 − 30 − 30 runs of the optimization based synthesis tools involved in our benchmark. As one can see, the results corresponding to the individual software tools (labeled by different colors) are in general close to each other, forming obliterated clusters of **data** points. The QSearch package provided the most accurate quantum circuits approximating the initial unitary. This observation was typical during our benchmark, QSearch turned to be the most precise synthesis tool in our comparisons. The decomposing precision of the QFAST and SQUANDER packages are close to each other, providing somewhat less precise circuits, but still close to the numerical precision of QSearch. From the point of CN OT gate count SQUANDER systematically provided the most optimal quantum circuits, with the minimum of 8 CN OT gates in the most optimal decomposition.