OMPCollapse¶
collapse: how many nested loops to share as one iteration space.
Declaration¶
Syntax¶
OMPCollapse(expr count)
Arguments¶
Argument |
Description |
|---|---|
|
how many loops to collapse. |
Return values¶
None.
Description¶
With collapse(2) the two outermost loops of the nest are flattened into a
single iteration space before the iterations are shared out, which gives the
threads more work to divide when the outer loop is short.
Examples¶
(OMPCollapse
:count (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
It comes from this complete ASR text document:
(TranslationUnit
:symtab (SymbolTable
:id 0
:symbols {
"main" (Program
:symtab (SymbolTable
:id 1
:symbols {
"a" (Variable
:parent_symtab 1
:name "a"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Array
:type (Integer
:kind 4
)
:dims [
(dimension
:start (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:length (IntegerConstant
:n 3
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:physical_type :FixedSizeArray
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"i" (Variable
:parent_symtab 1
:name "i"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"n" (Variable
:parent_symtab 1
:name "n"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"run" (Variable
:parent_symtab 1
:name "run"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Logical
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"total" (Variable
:parent_symtab 1
:name "total"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
}
)
:name "main"
:dependencies []
:body [
(OMPRegion
:region :Parallel
:clauses [
(OMPPrivate
:vars [
(Var
:v (SymbolRef 1 "i")
)
]
)
(OMPShared
:vars [
(Var
:v (SymbolRef 1 "a")
)
]
)
(OMPFirstPrivate
:vars [
(Var
:v (SymbolRef 1 "n")
)
]
)
(OMPNumThreads
:num_threads (IntegerConstant
:n 4
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPIf
:condition (Var
:v (SymbolRef 1 "run")
)
)
]
:body [
(OMPRegion
:region :Do
:clauses [
(OMPSchedule
:kind :Static
:chunk_size (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPCollapse
:count (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPReduction
:operator :ReduceAdd
:vars [
(Var
:v (SymbolRef 1 "total")
)
]
)
(OMPLastPrivate
:vars [
(Var
:v (SymbolRef 1 "i")
)
]
)
(OMPNowait)
]
:body [
(DoLoop
:name nil
:head (do_loop_head
:v (Var
:v (SymbolRef 1 "i")
)
:start (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:end (IntegerConstant
:n 3
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:increment (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
:body [
(Assignment
:target (Var
:v (SymbolRef 1 "total")
)
:value (IntegerBinOp
:left (Var
:v (SymbolRef 1 "total")
)
:op :Add
:right (Var
:v (SymbolRef 1 "i")
)
:type (Integer
:kind 4
)
:value nil
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
]
:orelse []
)
]
)
]
)
(OMPRegion
:region :Target
:clauses [
(OMPMap
:type :ToFrom
:vars [
(Var
:v (SymbolRef 1 "a")
)
]
)
(OMPDevice
:device (IntegerConstant
:n 0
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:body [
(OMPRegion
:region :Teams
:clauses [
(OMPNumTeams
:num_teams (IntegerConstant
:n 2
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPThreadLimit
:thread_limit (IntegerConstant
:n 64
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:body [
(Assignment
:target (Var
:v (SymbolRef 1 "total")
)
:value (IntegerConstant
:n 0
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
]
)
]
)
]
)
}
)
:items []
)