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63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
/****************************************************************
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****
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**** This file belongs with the course
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**** Introduction to Scientific Programming in C++/Fortran2003
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**** copyright 2016-2021 Victor Eijkhout eijkhout@tacc.utexas.edu
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****
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**** vectorcopy.cxx : example of vector copying
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****
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****************************************************************/
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#include <iostream>
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using std::cin;
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using std::cout;
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#include <cmath>
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using std::sqrt;
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#include <chrono>
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#include <vector>
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#include <array>
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int main() {
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{
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using clock = std::chrono::high_resolution_clock;
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clock::time_point point;
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static constexpr int T = 1000;
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static constexpr int N1 = 30;
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static constexpr int N2 = 30;
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static constexpr int N3 = 30;
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point = clock::now();
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std::array< std::array< std::array< std::array< double,N3 >,N2 >,N1 >, T> array;
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for ( int i1=0; i1<N1; i1++ )
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for ( int i2=0; i2<N2; i2++ )
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for ( int i3=0; i3<N3; i3++ )
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array[0][i1][i2][i3] = 15.;
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for ( int t=1; t<T; t++)
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for ( int i1=0; i1<N1; i1++ )
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for ( int i2=0; i2<N2; i2++ )
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for ( int i3=0; i3<N3; i3++ ) {
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double x = array[t-1][i1][i2][i3];
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array[t][i1][i2][i3] = sqrt(x);
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}
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double s=0;
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for ( int i1=0; i1<N1; i1++ )
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for ( int i2=0; i2<N2; i2++ )
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for ( int i3=0; i3<N3; i3++ )
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s += array[T-1][i1][i2][i3];
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auto duration = clock::now()-point;
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auto nanoseconds_duration =
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std::chrono::duration_cast<std::chrono::nanoseconds>(duration);
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cout << "Time in usec: "
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<< static_cast<int>( nanoseconds_duration.count()*1.e-3 ) << '\n';
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cout << s << '\n';
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}
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return 0;
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}
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