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https://github.com/triqs/dft_tools
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68 lines
1.7 KiB
ReStructuredText
68 lines
1.7 KiB
ReStructuredText
.. highlight:: c
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.. _STL:
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Iterators and STL
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##################################################################
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Standard iterators are provided that model the boost Mutable_ForwardIterator and ForwardIterator concepts
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(and hence are STL compliant).
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The iterator implements also two additional methods :
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* it can be casted to a bool : it is true iif the iteration is not at end.
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* it.indices() : returns const & to the indices at the point of the iteration.
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Examples::
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array<long,2> A (2,3);
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for (auto it = A.begin(); it; ++it) *it =it.indices()[0] + 10 *it.indices()[1];
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Some examples of usage :
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.. compileblock::
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#include <triqs/arrays.hpp>
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#include <vector>
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#include <map>
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#include <algorithm>
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using triqs::arrays::array; using triqs::arrays::matrix; using triqs::clef::placeholder;
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int main(){
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// For example, one can make a vector of arrays ... ::
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array<long,2> A (2,3);
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std::vector<array<long,2> > VV;
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VV.push_back(A);
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// ... or a map ::
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std::map<int, array<long,2> > MAP;
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MAP[1] = A;
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// We can put a std::vector in an array ... ::
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// --> should make a direct constructor for this.. + factory in the reverse direction...
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std::vector<int> V (10,2);
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array<int,1 > B(V.size()), C(V.size());
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std::copy(V.begin(),V.end(),B.begin());
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// ... or in reverse ::
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B*=2;
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std::copy(B.begin(),B.end(),V.begin());
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// ... or use other algorithms of std::
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std::cout<<" max(B) "<< * std::max_element(B.begin(),B.end())<<std::endl;
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// or replace
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placeholder<0> i_;
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B(i_) << 3*i_ ;
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std::cout<<" B "<< B << std::endl;
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std::replace_if (B.begin(), B.end(), [](int i) { return i>21;}, 0);
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std::cout<<" B "<< B << std::endl;
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}
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