\input zb-basic \input zb-ioport \iteman{io-port 06104333} \itemau{Sawerwain, Marek} \itemti{GPU-based parallel algorithms for transformations of quantum states expressed as vectors and density matrices.} \itemso{Wyrzykowski, Roman (ed.) et al., Parallel processing and applied mathematics. 9th international conference, PPAM 2011, Torun, Poland, September 11--14, 2011. Revised selected papers, Part I. Berlin: Springer (ISBN 978-3-642-31463-6/pbk). Lecture Notes in Computer Science 7203, 215-224 (2012).} \itemab Summary: In this paper the parallel algorithms to simulate measurements and unitary operations in the quantum computing model are presented. The proposed solutions are implemented using the CUDA technology. Moreover, a more effective routine for processing density matrices is presented. The main advantages of this approach are the reduced memory requirement and a good use of the computing power of the GPU hardware. Additionally, the proposed solution can be used to simulate circuits build from qubits or qudits. \itemrv{~} \itemcc{} \itemut{GPGPU; CUDA; parallel computations; quantum computations} \itemli{doi:10.1007/978-3-642-31464-3\_22} \end