LF95 Linux User's Guide - Lahey Computer Systems

Implementation SpecificationsIt is assumed that the reader has an understanding of OpenMP. LF64’s implementation ofOpenMP is described below.Implementation SpecificationsThis section gives details on features that are left processor-dependent by the OpenMP specificationalong with other specifications and restrictions.Nesting of Parallel RegionsNesting of parallel regions is supported.Dynamic Thread Adjustment FeaturesDynamic thread adjustment features are supported, and are on by default.Number of ThreadsThe number of threads for OpenMP is decided with the following priority.1 OMP_SET_NUM_THREADS service routine2 Environment variable OMP_NUM_THREADS3 Environment variable PARALLEL4 One threadSchedulingIf the schedule type for DO and PARALLEL DO directives is not specified by the SCHED-ULE clause, or the OMP_SCHEDULE environment variable, it defaults to STATIC.ASSIGN and Assigned GO TO StatementsAn ASSIGN statement within an OpenMP block cannot refer to a statement label that is outsideof the OpenMP directive block. Also, a statement label in an OpenMP directive blockcannot be referred to by an ASSIGN statement that is outside of the OpenMP directive block.Jumping into or out of a directive block area using an assigned GO TO statement is notsupported.Additional Functions and Operators in ATOMIC directive and REDUCTIONClauseThe following intrinsic functions and operators can be specified in an ATOMIC directive orREDUCTION clause.Intrinsic functions : AND, OROperators: .XOR., .EOR.Lahey/Fujitsu Linux64 Fortran User’s Guide 107