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#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>
#include <amgcl/amg.hpp>
#include <amgcl/adapter/crs_tuple.hpp>
#include <amgcl/backend/block_crs.hpp>
#include <amgcl/coarsening/aggregation.hpp>
#include <amgcl/relaxation/spai0.hpp>
#include <amgcl/solver/bicgstab.hpp>
#include <amgcl/profiler.hpp>
namespace amgcl {
profiler<> prof("v2");
}
int main() {
using amgcl::prof;
typedef amgcl::backend::block_crs<double> Backend;
typedef amgcl::amg<
Backend,
amgcl::coarsening::aggregation,
amgcl::relaxation::spai0
> AMG;
std::vector<ptrdiff_t> ptr;
std::vector<ptrdiff_t> col;
std::vector<double> val;
std::vector<double> rhs;
prof.tic("read");
{
std::istream_iterator<int> iend;
std::istream_iterator<double> dend;
std::ifstream fptr("rows.txt");
std::ifstream fcol("cols.txt");
std::ifstream fval("values.txt");
std::ifstream frhs("rhs.txt");
amgcl::precondition(fptr, "rows.txt not found");
amgcl::precondition(fcol, "cols.txt not found");
amgcl::precondition(fval, "values.txt not found");
amgcl::precondition(frhs, "rhs.txt not found");
std::istream_iterator<int> iptr(fptr);
std::istream_iterator<int> icol(fcol);
std::istream_iterator<double> ival(fval);
std::istream_iterator<double> irhs(frhs);
ptr.assign(iptr, iend);
col.assign(icol, iend);
val.assign(ival, dend);
rhs.assign(irhs, dend);
}
int n = ptr.size() - 1;
prof.toc("read");
prof.tic("build");
AMG::params prm;
prm.coarsening.aggr.eps_strong = 0;
prm.coarsening.aggr.block_size = 4;
prm.npre = prm.npost = 2;
Backend::params bprm;
bprm.block_size = 4;
AMG amg(std::tie(n, ptr, col, val), prm, bprm);
prof.toc("build");
std::cout << amg << std::endl;
std::vector<double> x(n, 0);
amgcl::solver::bicgstab<AMG::backend_type> solve(n);
prof.tic("solve");
size_t iters;
double resid;
std::tie(iters, resid) = solve(amg, rhs, x);
prof.toc("solve");
std::cout << "Iterations: " << iters << std::endl
<< "Error: " << resid << std::endl
<< std::endl;
std::cout << amgcl::prof << std::endl;
}
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