How to specify levels . . .
by Tom Parker
There are three main types of F90 compiler optimization on SCD Cray computers: vector, scalar, and autotasking (task). You can specify the desired level (0-3) of each type with the f90 -O option -- either individually, by using specific levels, or all three types at once, by using a general level.Reference information
For more information on optimization options, see Section 2.2.19 of the CF90 Commands and Directives Reference Manual, SR-3901 3.0.