Debug printing

For quick debugging in C++, XDiag features a simple macro which outputs the name and content of a variable calles XDIAG_SHOW(x). For example

Spinhalf block(16, 8);
XDIAG_SHOW(block);

will write an output similar to

block:
  n_sites  : 16
  n_up     : 8
  dimension: 12,870
  ID       : 0xa9127434d66b9878

The XDIAG_SHOW(x) macro can be used on any XDiag object and several other standard C++ objects as well.