getrf.hpp

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// Copyright (c) 2021--present, The Simons Foundation
// This file is part of TRIQS/nda and is licensed under the Apache License, Version 2.0.
// SPDX-License-Identifier: Apache-2.0
// See LICENSE in the root of this distribution for details.

 
#pragma once
 
#include "./interface/cxx_interface.hpp"
#include "../basic_functions.hpp"
#include "../concepts.hpp"
#include "../layout_transforms.hpp"
#include "../macros.hpp"
#include "../mem/address_space.hpp"
#include "../traits.hpp"
 
#ifndef NDA_HAVE_DEVICE
#include "../device.hpp"
#endif // NDA_HAVE_DEVICE
 
#include <algorithm>
#include <type_traits>
 
namespace nda::lapack {

  template <MemoryMatrix A, MemoryVector IPIV>
    requires(mem::have_compatible_addr_space<A, IPIV> and is_blas_lapack_v<get_value_t<A>> and std::is_same_v<get_value_t<IPIV>, int>)
  int getrf(A &&a, IPIV &&ipiv) { // NOLINT (temporary views are allowed here)
    // for C-layout arrays/views, call getrf with the transpose
    if constexpr (has_C_layout<A>) return getrf(transpose(a), ipiv);
 
    // check the dimensions of the input/output arrays/views and resize if necessary
    auto const [m, n] = a.shape();
    resize_or_check_if_view(ipiv, {std::min(m, n)});
 
    // arrays/views must be LAPACK compatible
    EXPECTS(a.indexmap().min_stride() == 1);
    EXPECTS(ipiv.indexmap().min_stride() == 1);
 
#if defined(__has_feature)
#if __has_feature(memory_sanitizer)
    ipiv = 0;
#endif
#endif
 
    // perform actual library call
    int info = 0;
    if constexpr (mem::have_device_compatible_addr_space<A, IPIV>) {
#if defined(NDA_HAVE_DEVICE)
      device::getrf(m, n, a.data(), get_ld(a), ipiv.data(), info);
#else
      compile_error_no_gpu();
#endif
    } else {
      f77::getrf(m, n, a.data(), get_ld(a), ipiv.data(), info);
    }
    return info;
  }
 
} // namespace nda::lapack