Place your C3tensor routines at the indicated location in the program
``pvector.C'' from Appendix C. You now should be able
to compile and run the program for various box dimensions. At this
stage, the main program allocates space for 3 pvectors (v1, v2, v3),
fills them in with random numbers, computes the magnitude of each
( 
v^v), and finally tests the mathematical identity that 
.