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distribution.cc
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1 /*!
2  *
3  * Copyright (C) 2015 Technical University of Liberec. All rights reserved.
4  *
5  * This program is free software; you can redistribute it and/or modify it under
6  * the terms of the GNU General Public License version 3 as published by the
7  * Free Software Foundation. (http://www.gnu.org/licenses/gpl-3.0.en.html)
8  *
9  * This program is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
12  *
13  *
14  * @file distribution.cc
15  * @ingroup system
16  * @brief Objects and functions for mesh partitioning.
17  */
18 
19 #include "system/global_defs.h"
20 #include "system/system.hh"
21 #include "distribution.hh"
22 
23 /**
24  * create a Distribution from local sizes (dim = np )
25  * (collective context)
26  */
27 Distribution::Distribution(const unsigned int size, MPI_Comm comm)
28 :communicator(comm),
29 lsizes(NULL)
30 {
33 // TODO: zavest odchytavani vyjimek a pouzivat new a delete
34 
35  // communicate global sizes array
36  starts= new unsigned int [np()+1];
37  unsigned int lsize=size; // since size is const
39  // count starts
40  starts[0]=0;
41  for( unsigned int i=1 ; i<=np(); i++) starts[i]+=starts[i-1];
42 }
43 
44 /**
45  * create a Distribution from local sizes (dim = np )
46  * (local context)
47  */
48 Distribution::Distribution(const unsigned int * const sizes, MPI_Comm comm)
49 :communicator(comm),
50  lsizes(NULL)
51 {
54 // TODO: zavest odchytavani vyjimek a pouzivat new a delete
55  starts= new unsigned int [np()+1];
56  starts[0]=0;
57  for(unsigned int i=0 ; i<np(); i++) starts[i+1]=starts[i]+sizes[i];
58 }
59 
60 /**
61  * constructor from existing PETSC vector
62  * (collective context)
63  */
64 Distribution::Distribution(const Vec &petsc_vector)
65 :communicator(PETSC_COMM_WORLD),
66  lsizes(NULL)
67 {
70 
71  const PetscInt *petsc_starts;
72  chkerr(VecGetOwnershipRanges(petsc_vector,&petsc_starts));
73 
74  starts= new unsigned int [np()+1];
75  for(unsigned int i=0 ; i<=np(); i++) starts[i]=petsc_starts[i];
76 }
77 
78 /**
79  * construct from given global size
80  * (collective context)
81  */
82 Distribution::Distribution(const DistributionType &type, unsigned int global_size, MPI_Comm comm)
83 :communicator(comm),
84  lsizes(NULL)
85 {
88  ASSERT_PERMANENT_GT( num_of_procs, 0).error("MPI size is not positive, possibly broken MPI communicator.\n");
89 
90  if (type.type_ == Block) {
91  unsigned int reminder, per_proc;
92 
93  reminder=global_size % np(); per_proc=global_size / np();
94  // set perproc rows to each proc, but for first "reminder" procs set one row more
95  starts= new unsigned int [np()+1];
96  starts[0]=0;
97  for(unsigned int i=0; i<np(); i++)
98  starts[i+1]=starts[i]+per_proc+(i<reminder?1:0);
99 
100  } else if (type.type_ == Localized) {
101 
102  starts= new unsigned int [np()+1];
103  starts[0]=0;
104  for(unsigned int i=1; i<=np(); i++) starts[i]=global_size;
105  }
106  else {
107  ASSERT_PERMANENT(0).error("Cyclic distribution is not yet implemented.\n");
108  }
109  }
110 /**
111  * copy constructor
112  *
113  */
115 : communicator(distr.communicator)
116 {
118  my_proc=distr.my_proc;
119  starts= new unsigned int [np()+1];
120  memcpy(starts,distr.starts,(np()+1) * sizeof(unsigned int));
121  lsizes=NULL;
122 }
123 
124 
125 /**
126  * find the proc to which belongs index "idx" in the distribution
127  * use simple linear search, better binary search could be implemented
128  * (local context)
129  */
130 unsigned int Distribution::get_proc(unsigned int idx) const
131 {
132  ASSERT_PTR( starts ).error("Distribution is not initialized.\n");
133  ASSERT_LT(idx, size()).error("Index is greater than distribution size.\n");
134 
135  for(unsigned int i=0; i<np(); i++) {
136  if (is_on_proc(idx,i)) return (i);
137  }
138  ASSERT_PERMANENT(0)(idx).error("Can not find owner of given index.\n");
139  return (-1);
140 }
141 
142 const unsigned int * Distribution::get_lsizes_array()
143 {
144  if ( lsizes == NULL ) {
145  lsizes= new unsigned int [np()];
146  for(unsigned int i=0;i<np();i++) lsizes[i]=lsize(i);
147  }
148 
149  return lsizes;
150 }
151 
152 
153 
154 const unsigned int * Distribution::get_starts_array() const {
155  return starts;
156 }
157 
158 
159 
160 void Distribution::view(std::ostream &stream) const
161 {
162  stream << "[" <<myp() << "]" << "Distribution size: " << size() << " lsize: " << lsize() << " offset: " << begin() << " mpi_size: " << np() << endl;
163  for(unsigned int i=0; i<np();++i)
164  stream << "[" <<myp() << "]" << "proc: " << i << " offset: " << begin(i) << " lsize: " << lsize(i) << endl;
165 }
166 
167 /**
168  * Destructor.
169  */
171 {
172 // TODO: zavest odchytavani vyjimek a pouzivat new a delete
173  delete [] starts;
174  if (lsizes) delete [] lsizes;
175 }
176 
#define ASSERT_PERMANENT(expr)
Allow use shorter versions of macro names if these names is not used with external library.
Definition: asserts.hh:348
#define ASSERT_LT(a, b)
Definition of comparative assert macro (Less Than) only for debug mode.
Definition: asserts.hh:301
#define ASSERT_PERMANENT_GT(a, b)
Definition of comparative assert macro (Greater Than)
Definition: asserts.hh:313
#define ASSERT_PTR(ptr)
Definition of assert macro checking non-null pointer (PTR) only for debug mode.
Definition: asserts.hh:341
const unsigned int * get_lsizes_array()
get local sizes array
unsigned int * starts
starts[i] index of the first index on the proc i; starts[n_procs]=size of whole array
const unsigned int * get_starts_array() const
get local starts array
unsigned int myp() const
get my processor
bool is_on_proc(unsigned int idx, unsigned int proc) const
int num_of_procs
number of procs
Distribution(const unsigned int size, MPI_Comm comm)
Definition: distribution.cc:27
unsigned int * lsizes
local sizes
void view(std::ostream &stream) const
distribution view
unsigned int get_proc(unsigned int idx) const
get processor of the given index
unsigned int lsize() const
unsigned int size() const
get global size
unsigned int np() const
get num of processors
int my_proc
my proc number
const MPI_Comm communicator
communicator
unsigned int begin() const
Support classes for parallel programing.
Global macros to enhance readability and debugging, general constants.
#define MPI_INT
Definition: mpi.h:160
#define MPI_Comm_size
Definition: mpi.h:235
int MPI_Comm
Definition: mpi.h:141
#define MPI_Allgather(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype, comm)
Definition: mpi.h:580
#define MPI_Comm_rank
Definition: mpi.h:236
void chkerr(unsigned int ierr)
Replacement of new/delete operator in the spirit of xmalloc.
Definition: system.hh:142