  QCMPI is a quantum computer (QC) simulation package written in Fortran 90
with parallel processing capabilities. It is an accessible research tool that
permits rapid evaluation of quantum algorithms for a large number of qubits and
for various "noise" scenarios. The prime motivation for developing QCMPI is to
facilitate numerical examination of not only how QC algorithms work, but also
to include noise, decoherence, and attenuation effects and to evaluate the
efficacy of error correction schemes. The present work builds on an earlier
Mathematica code QDENSITY, which is mainly a pedagogic tool. In QCMPI, the
stress is on state vectors, in order to employ a large number of qubits. The
parallel processing feature is implemented by using the Message-Passing
Interface (MPI) protocol.
  Codes for Grover's search and Shor's factoring algorithms are provided as
examples. A major feature of this work is that concurrent versions of the
algorithms can be evaluated with each version subject to alternate noise
effects, which corresponds to the idea of solving a stochastic Schr\"{o}dinger
equation.
