Rheolef  7.1
an efficient C++ finite element environment
csr_to_asr.h
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1 #ifndef _CSR_TO_ASR_H
2 #define _CSR_TO_ASR_H
23 
24 namespace rheolef {
25 /*F:
26 NAME: csr_to_asr -- sequential sparse matrix convertion (@PACKAGE@ @VERSION@)
27 DESCRIPTION:
28  Convert sequential "csr" to sequential "asr" sparse matrix format.
29 ALGORITHM:
30  csr_build_from_asr
31 
32  "input": the sparse asr matrix
33  | ia(0:nrow-1), a(0:nnz-1)
34  | ib(0:2*nrow+1), op(.)
35  "ouput": the sparse csr matrix
36  | b(0:nnz-1)
37  begin
38  | q := 0
39  | for i := 0 to nrow-1 do
40  | q := ib(2*i)
41  | for p := ia(i) to ia(i+1)-1 do
42  | b(q) := op(a(p))
43  | q := q + 1
44  | endfor
45  | endfor
46  end
47 COMPLEXITY:
48  Time and memory complexity is O(nnz).
49 NOTE:
50  The output arrays are supposed to be coorectly allocated,
51  i.e. large enough.
52 
53  The pointer array "ib" is taken as input parameter,
54  since practical C++ "asr" implementation uses STL "map"
55  for data storage. Thus "ib(.)" is an array of STL map,
56  and this algorithm is only formal.
57  METHODS: @csr_to_asr
58 AUTHORS:
59  LMC-IMAG, 38041 Grenoble cedex 9, France
60  | Pierre.Saramito@imag.fr
61 DATE: 22 march 1999
62 END:
63 */
64 //<csr_to_asr:
65 template <
66  class InputPtrIterator,
67  class InputDataIterator,
68  class UnaryOperation,
69  class OutputPtrIterator>
70 OutputPtrIterator
72  InputPtrIterator iter_ptr_a,
73  InputPtrIterator last_ptr_a,
74  InputDataIterator iter_data_a,
75  UnaryOperation op,
76  OutputPtrIterator iter_ptr_b)
77 {
78  InputPtrIterator first_ptr_a = iter_ptr_a;
79  InputDataIterator first_data_a = iter_data_a;
80  InputPtrIterator next_ptr_a = iter_ptr_a;
81  next_ptr_a++;
82  while (next_ptr_a != last_ptr_a) {
83  InputDataIterator last_data_a = (*next_ptr_a);
84  while (iter_data_a != last_data_a) {
85  (*iter_ptr_b).insert(op(*iter_data_a));
86  iter_data_a++;
87  }
88  next_ptr_a++;
89  iter_ptr_b++;
90  }
91  return iter_ptr_b;
92 }
93 //>csr_to_asr:
94 } // namespace rheolef
95 #endif // _CSR_TO_ASR_H
This file is part of Rheolef.
OutputPtrIterator csr_to_asr(InputPtrIterator iter_ptr_a, InputPtrIterator last_ptr_a, InputDataIterator iter_data_a, UnaryOperation op, OutputPtrIterator iter_ptr_b)
Definition: csr_to_asr.h:71