lascl.hpp

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//
// Copyright (c) 2021-2023, University of Colorado Denver. All rights reserved.
//
// This file is part of <T>LAPACK.
// <T>LAPACK is free software: you can redistribute it and/or modify it under
// the terms of the BSD 3-Clause license. See the accompanying LICENSE file.
 
#ifndef TLAPACK_LEGACY_LASCL_HH
#define TLAPACK_LEGACY_LASCL_HH
 
#include "tlapack/base/types.hpp"
#include "tlapack/lapack/lascl.hpp"
 
namespace tlapack {
namespace legacy {
 
    template <class matrixtype_t, typename T>
    int lascl(matrixtype_t matrixtype,
              idx_t kl,
              idx_t ku,
              const real_type<T>& b,
              const real_type<T>& a,
              idx_t m,
              idx_t n,
              T* A,
              idx_t lda)
    {
        using internal::create_banded_matrix;
        using internal::create_matrix;
 
        // check arguments
        tlapack_check_false((matrixtype != MatrixType::General) &&
                            (matrixtype != MatrixType::Lower) &&
                            (matrixtype != MatrixType::Upper) &&
                            (matrixtype != MatrixType::Hessenberg) &&
                            (matrixtype != MatrixType::LowerBand) &&
                            (matrixtype != MatrixType::UpperBand) &&
                            (matrixtype != MatrixType::Band));
        tlapack_check_false(((matrixtype == MatrixType::LowerBand) ||
                             (matrixtype == MatrixType::UpperBand) ||
                             (matrixtype == MatrixType::Band)) &&
                            ((kl < 0) || (kl > max(m - 1, idx_t(0)))));
        tlapack_check_false(((matrixtype == MatrixType::LowerBand) ||
                             (matrixtype == MatrixType::UpperBand) ||
                             (matrixtype == MatrixType::Band)) &&
                            ((ku < 0) || (ku > max(n - 1, idx_t(0)))));
        tlapack_check_false(((matrixtype == MatrixType::LowerBand) ||
                             (matrixtype == MatrixType::UpperBand)) &&
                            (kl != ku));
        tlapack_check_false(m < 0);
        tlapack_check_false((lda < m) &&
                            ((matrixtype == MatrixType::General) ||
                             (matrixtype == MatrixType::Lower) ||
                             (matrixtype == MatrixType::Upper) ||
                             (matrixtype == MatrixType::Hessenberg)));
        tlapack_check_false((matrixtype == MatrixType::LowerBand) &&
                            (lda < kl + 1));
        tlapack_check_false((matrixtype == MatrixType::UpperBand) &&
                            (lda < ku + 1));
        tlapack_check_false((matrixtype == MatrixType::Band) &&
                            (lda < 2 * kl + ku + 1));
 
        if (matrixtype == MatrixType::LowerBand) {
            auto A_ = create_banded_matrix<T>(A, m, n, kl, 0);
            return lascl(BandAccess{size_t(kl), 0}, b, a, A_);
        }
        else if (matrixtype == MatrixType::UpperBand) {
            auto A_ = create_banded_matrix<T>(A, m, n, 0, ku);
            return lascl(BandAccess{0, size_t(ku)}, b, a, A_);
        }
        else if (matrixtype == MatrixType::Band) {
            auto A_ = create_banded_matrix<T>(A, m, n, kl, ku);
            return lascl(BandAccess{size_t(kl), size_t(ku)}, b, a, A_);
        }
        else {
            auto A_ = create_matrix<T>(A, m, n, lda);
 
            if (matrixtype == MatrixType::General) {
                return lascl(GENERAL, b, a, A_);
            }
            else if (matrixtype == MatrixType::Lower) {
                return lascl(LOWER_TRIANGLE, b, a, A_);
            }
            else if (matrixtype == MatrixType::Upper) {
                return lascl(UPPER_TRIANGLE, b, a, A_);
            }
            else  // if (matrixtype == MatrixType::Hessenberg)
            {
                return lascl(UPPER_HESSENBERG, b, a, A_);
            }
        }
    }
 
}  // namespace legacy
}  // namespace tlapack
 
#endif  // TLAPACK_LEGACY_LASCL_HH