+---------------------------------Fortran 95---------------------------------+
Purpose
The FORALL (Construct) statement is the first statement of the FORALL construct.
Format
>>-+----------------------------+--FORALL--+---------------+--->< '-FORALL_construct_name-- : -' '-forall_header-' |
>>-(--forall_triplet_spec_list--+---------------------+--)-----><
'-,--scalar_mask_expr-'
|
>>-index_name-- = --subscript-- : --subscript-------------------> >--+-------------+--------------------------------------------->< '- : --stride-' |
Rules
Any procedures that are referenced in the mask expression of forall_header (including one referenced by a defined operation or assignment) must be pure.
The index_name must be a scalar integer variable. The scope of index_name is the whole FORALL construct.
In forall_triplet_spec_list, neither a subscript nor a stride can contain a reference to any index_name in the forall_triplet_spec_list. Evaluation of any expression in forall_header must not affect evaluation of any other expression in forall_header.
Given the following forall_triplet_spec:
index1 = s1:s2:s3
The maximum number of index values is determined by:
max = INT((s2-s1+s3)/s3)
If the stride (s3 above) is not specified, a value of 1 is assumed. If max <= 0 for any index, forall_assignment is not executed. For example:
index1 = 2:10:3 ! The index values are 2,5,8.
! max = floor(((10-2)/3)+1) = 3.
index2 = 6:2:-1 ! The index values are 6,5,4,3,2.
index2 = 6:2 ! No index values.
If the mask expression is omitted, a value of .TRUE. is assumed.
Examples
POSITIVE: FORALL (X=1:100,A(X)>0) I(X)=I(X)+J(X) J(X)=J(X)-I(X+1) END FORALL POSITIVE
Related Information
+-----------------------------End of Fortran 95------------------------------+