  Quantum computing is a radical new paradigm for a technology that is capable
to revolutionize information processing. Simulators of universal quantum
computer are important for understanding the basic principles and operations of
the current noisy intermediate-scale quantum (NISQ) processors, and for
building in future fault-tolerant quantum computers. In this work, we present
simulation of universal quantum computers by introducing Psitrum -- a universal
gate-model quantum computer simulator implemented on classical hardware. The
simulator allows to emulate and debug quantum algorithms in form of quantum
circuits for many applications with the choice of adding variety of noise
modules to simulate decoherence in quantum circuits. Psitrum allows to simulate
all basic quantum operations and provides variety of visualization tools. The
simulator allows to trace out all possible quantum states at each stage M of an
N-qubit implemented quantum circuit. Psitrum software and source codes are
freely available at: (github.com/moghadeer/Psitrum).
