Dear Juleana and Xinda, please find attached the reference solutions to sheet 2 and sheet 3. Note that the PCA notebook has to be run with all the additional files you can download from the webseite, i.e. the data sets and the predefined plotting/slicing functions. Best regards, Bastian -- Dr. Bastian Bohn Institut für Numerische Simulation Rheinische Friedrich-Wilhelms-Universität Bonn Wegelerstr. 6 D-53115 Bonn Germany Tel.: +49 228 73-60452 Fax: +49 228 73-7527 URL: http://wissrech.ins.uni-bonn.de/people/bohn.html