WHERE statement
http://scv.bu.edu/computation/bluegene/IBMdocs/compiler/xlf-10.1/html/xlflr/where.htm
OpenMP: 数组、DO循环、REDUCTION
https://stackoverflow.com/questions/24882425/openmp-array-reductions-with-fortran
http://scv.bu.edu/computation/bluegene/IBMdocs/compiler/xlf-10.1/html/xlflr/where.htm
https://stackoverflow.com/questions/24882425/openmp-array-reductions-with-fortran