array(2rheolef) rheolef-6.1 array(2rheolef)
NAME
array - container in distributed environment (rheolef-6.1)
SYNOPSYS
STL-like vector container for a distributed memory machine model.
EXAMPLE
A sample usage of the class is:
int main(int argc, char**argv) {
environment distributed(argc, argv);
array<double> x(distributor(100), 3.14);
dout << x << endl;
}
The array<T> interface is similar to those of the std::vector<T> with the addition of some communication features in the distributed case:
write accesses with entry/assembly and read access with dis_at.
DISTRIBUTED WRITE ACCESS
Loop on any dis_i that is not managed by the current processor:
x.dis_entry (dis_i) = value;
and then, after loop, perform all communication:
x.dis_entry_assembly();
After this command, each value is stored in the array, available the processor associated to dis_i.
DISTRIBUTED READ ACCESS
First, define the set of indexes:
std::set<size_t> ext_idx_set;
Then, loop on dis_i indexes that are not managed by the current processor:
ext_idx_set.insert (dis_i);
After the loop, performs the communications:
x.set_dis_indexes (ext_idx_set);
After this command, each values associated to the dis_i index, and that belongs to the index set, is now available also on the current pro-
cessor as:
value = x.dis_at (dis_i);
For convenience, if dis_i is managed by the current processor, this function returns also the value.
NOTE
The class takes two template parameters: one for the type T and the second for the memory model M, that could be either M=distributed or
M=sequential. The two cases are associated to two diferent implementations, but proposes exactly the same interface. The sequential inter-
face propose also a supplementary constructor:
array<double,sequential> x(local_size, init_val);
This constructor is a STL-like one but could be consufused in the distributed case, since there are two sizes: a local one and a global
one. In that case, the use of the distributor, as a generalization of the size concept, clarify the situation (see distributor(2)).
IMPLEMENTATION NOTE
"scatter" via "get_dis_entry".
"gather" via "dis_entry(dis_i) = value" or "dis_entry(dis_i) += value". Note that += applies when T=idx_set where idx_set is a wrapper
class of std::set<size_t> ; the += operator represents the union of a set. The operator= is used when T=double or others simple T types
without algebra. If there is a conflict, i.e. several processes set the dis_i index, then the result of operator+= depends upon the order
of the process at each run and is not deterministic. Such ambiguous behavior is not detected yet at run time.
IMPLEMENTATION
template <class T, class A>
class array<T,sequential,A> : public smart_pointer<array_seq_rep<T,A> > {
public:
// typedefs:
typedef array_seq_rep<T,A> rep;
typedef smart_pointer<rep> base;
typedef sequential memory_type;
typedef typename rep::size_type size_type;
typedef typename rep::difference_type difference_type;
typedef typename rep::value_type value_type;
typedef typename rep::reference reference;
typedef typename rep::dis_reference dis_reference;
typedef typename rep::iterator iterator;
typedef typename rep::const_reference const_reference;
typedef typename rep::const_iterator const_iterator;
// allocators:
array (size_type loc_size = 0, const T& init_val = T(), const A& alloc = A());
void resize (size_type loc_size = 0, const T& init_val = T());
array (const distributor& ownership, const T& init_val = T(), const A& alloc = A());
void resize (const distributor& ownership, const T& init_val = T());
// local accessors & modifiers:
A get_allocator() const { return base::data().get_allocator(); }
size_type size () const { return base::data().size(); }
size_type dis_size () const { return base::data().dis_size(); }
const distributor& ownership() const { return base::data().ownership(); }
const communicator& comm() const { return ownership().comm(); }
reference operator[] (size_type i) { return base::data().operator[] (i); }
const_reference operator[] (size_type i) const { return base::data().operator[] (i); }
reference operator() (size_type i) { return base::data().operator[] (i); }
const_reference operator() (size_type i) const { return base::data().operator[] (i); }
const_reference dis_at (size_type dis_i) const { return operator[] (dis_i); }
iterator begin() { return base::data().begin(); }
const_iterator begin() const { return base::data().begin(); }
iterator end() { return base::data().end(); }
const_iterator end() const { return base::data().end(); }
// global modifiers (for compatibility with distributed interface):
dis_reference dis_entry (size_type dis_i) { return base::data().dis_entry(dis_i); }
void dis_entry_assembly() {}
template<class SetOp> void dis_entry_assembly(SetOp my_set_op) {}
template<class SetOp> void dis_entry_assembly_begin (SetOp my_set_op) {}
template<class SetOp> void dis_entry_assembly_end (SetOp my_set_op) {}
void reset_dis_indexes() const {}
template<class Set> void set_dis_indexes (const Set& ext_idx_set) const {}
template<class Set> void append_dis_indexes (const Set& ext_idx_set) const {}
template<class Set, class Map> void append_dis_entry (const Set& ext_idx_set, Map& ext_idx_map) const {}
template<class Set, class Map> void get_dis_entry (const Set& ext_idx_set, Map& ext_idx_map) const {}
// apply a partition:
template<class RepSize>
void repartition ( // old_numbering for *this
const RepSize& partition, // old_ownership
array<T,sequential,A>& new_array, // new_ownership (created)
RepSize& old_numbering, // new_ownership
RepSize& new_numbering) const // old_ownership
{ return base::data().repartition (partition, new_array, old_numbering, new_numbering); }
template<class RepSize>
void permutation_apply ( // old_numbering for *this
const RepSize& new_numbering, // old_ownership
array<T,sequential,A>& new_array) const // new_ownership (already allocated)
{ return base::data().permutation_apply (new_numbering, new_array); }
void reverse_permutation ( // old_ownership for *this=iold2dis_inew
array<size_type,sequential,A>& inew2dis_iold) const // new_ownership
{ base::data().reverse_permutation (inew2dis_iold.data()); }
// i/o:
odiststream& put_values (odiststream& ops) const { return base::data().put_values(ops); }
idiststream& get_values (idiststream& ips) { return base::data().get_values(ips); }
template <class GetFunction>
idiststream& get_values (idiststream& ips, GetFunction get_element) { return base::data().get_values(ips, get_element); }
template <class PutFunction>
odiststream& put_values (odiststream& ops, PutFunction put_element) const { return base::data().put_values(ops, put_element); }
void dump (std::string name) const { return base::data().dump(name); }
};
IMPLEMENTATION
template <class T, class A>
class array<T,distributed,A> : public smart_pointer<array_mpi_rep<T,A> > {
public:
// typedefs:
typedef array_mpi_rep<T,A> rep;
typedef smart_pointer<rep> base;
typedef distributed memory_type;
typedef typename rep::size_type size_type;
typedef typename rep::difference_type difference_type;
typedef typename rep::value_type value_type;
typedef typename rep::reference reference;
typedef typename rep::dis_reference dis_reference;
typedef typename rep::iterator iterator;
typedef typename rep::const_reference const_reference;
typedef typename rep::const_iterator const_iterator;
typedef typename rep::scatter_map_type scatter_map_type;
// allocators:
array (const distributor& ownership = distributor(), const T& init_val = T(), const A& alloc = A());
void resize (const distributor& ownership = distributor(), const T& init_val = T());
// local accessors & modifiers:
A get_allocator() const { return base::data().get_allocator(); }
size_type size () const { return base::data().size(); }
size_type dis_size () const { return base::data().dis_size(); }
const distributor& ownership() const { return base::data().ownership(); }
const communicator& comm() const { return base::data().comm(); }
reference operator[] (size_type i) { return base::data().operator[] (i); }
const_reference operator[] (size_type i) const { return base::data().operator[] (i); }
reference operator() (size_type i) { return base::data().operator[] (i); }
const_reference operator() (size_type i) const { return base::data().operator[] (i); }
iterator begin() { return base::data().begin(); }
const_iterator begin() const { return base::data().begin(); }
iterator end() { return base::data().end(); }
const_iterator end() const { return base::data().end(); }
// global accessor:
template<class Set, class Map>
void append_dis_entry (const Set& ext_idx_set, Map& ext_idx_map) const { base::data().append_dis_entry (ext_idx_set, ext_idx_map); }
template<class Set, class Map>
void get_dis_entry (const Set& ext_idx_set, Map& ext_idx_map) const { base::data().get_dis_entry (ext_idx_set, ext_idx_map); }
template<class Set>
void append_dis_indexes (const Set& ext_idx_set) const { base::data().append_dis_indexes (ext_idx_set); }
void reset_dis_indexes() const { base::data().reset_dis_indexes(); }
template<class Set>
void set_dis_indexes (const Set& ext_idx_set) const { base::data().set_dis_indexes (ext_idx_set); }
const T& dis_at (size_type dis_i) const { return base::data().dis_at (dis_i); }
// get all external pairs (dis_i, values):
const scatter_map_type& get_dis_map_entries() const { return base::data().get_dis_map_entries(); }
// global modifiers (for compatibility with distributed interface):
dis_reference dis_entry (size_type dis_i) { return base::data().dis_entry(dis_i); }
void dis_entry_assembly() { return base::data().dis_entry_assembly(); }
template<class SetOp>
void dis_entry_assembly (SetOp my_set_op) { return base::data().dis_entry_assembly (my_set_op); }
template<class SetOp>
void dis_entry_assembly_begin (SetOp my_set_op) { return base::data().dis_entry_assembly_begin (my_set_op); }
template<class SetOp>
void dis_entry_assembly_end (SetOp my_set_op) { return base::data().dis_entry_assembly_end (my_set_op); }
// apply a partition:
template<class RepSize>
void repartition ( // old_numbering for *this
const RepSize& partition, // old_ownership
array<T,distributed>& new_array, // new_ownership (created)
RepSize& old_numbering, // new_ownership
RepSize& new_numbering) const // old_ownership
{ return base::data().repartition (partition.data(), new_array.data(), old_numbering.data(), new_numbering.data()); }
template<class RepSize>
void permutation_apply ( // old_numbering for *this
const RepSize& new_numbering, // old_ownership
array<T,distributed,A>& new_array) const // new_ownership (already allocated)
{ base::data().permutation_apply (new_numbering.data(), new_array.data()); }
void reverse_permutation ( // old_ownership for *this=iold2dis_inew
array<size_type,distributed,A>& inew2dis_iold) const // new_ownership
{ base::data().reverse_permutation (inew2dis_iold.data()); }
// i/o:
odiststream& put_values (odiststream& ops) const { return base::data().put_values(ops); }
idiststream& get_values (idiststream& ips) { return base::data().get_values(ips); }
void dump (std::string name) const { return base::data().dump(name); }
template <class GetFunction>
idiststream& get_values (idiststream& ips, GetFunction get_element) { return base::data().get_values(ips, get_element); }
template <class PutFunction>
odiststream& put_values (odiststream& ops, PutFunction put_element) const { return base::data().put_values(ops, put_element); }
template <class PutFunction, class A2> odiststream& permuted_put_values (
odiststream& ops, const array<size_type,distributed,A2>& perm, PutFunction put_element) const
{ return base::data().permuted_put_values (ops, perm.data(), put_element); }
};
SEE ALSO
distributor(2)
rheolef-6.1 rheolef-6.1 array(2rheolef)