bidiag.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_BIDIAG_HH
#define TLAPACK_BIDIAG_HH
 
#include "tlapack/base/utils.hpp"
#include "tlapack/lapack/gebd2.hpp"
#include "tlapack/lapack/gebrd.hpp"
 
namespace tlapack {
 
enum class BidiagVariant : char { Level2 = '2', Blocked = 'B' };
 
struct BidiagOpts : public GebrdOpts {
    BidiagVariant variant = BidiagVariant::Blocked;
};
 
template <class T, TLAPACK_SMATRIX matrix_t, TLAPACK_SVECTOR vector_t>
constexpr WorkInfo bidiag_worksize(const matrix_t& A,
                                   const vector_t& tauv,
                                   const vector_t& tauw,
                                   const BidiagOpts& opts = {})
{
    // Call variant
    if (opts.variant == BidiagVariant::Level2)
        return gebd2_worksize<T>(A, tauv, tauw);
    else
        return gebrd_worksize<T>(A, tauv, tauw, opts);
}
 
template <TLAPACK_SMATRIX matrix_t,
          TLAPACK_SVECTOR vector_t,
          TLAPACK_WORKSPACE work_t>
int bidiag_work(matrix_t& A,
                vector_t& tauv,
                vector_t& tauw,
                work_t& work,
                const BidiagOpts& opts = {})
{
    // Call variant
    if (opts.variant == BidiagVariant::Level2)
        return gebd2_work(A, tauv, tauw, work);
    else
        return gebrd_work(A, tauv, tauw, work, opts);
}
 
template <TLAPACK_SMATRIX matrix_t, TLAPACK_SVECTOR vector_t>
int bidiag(matrix_t& A,
           vector_t& tauv,
           vector_t& tauw,
           const BidiagOpts& opts = {})
{
    // Call variant
    if (opts.variant == BidiagVariant::Level2)
        return gebd2(A, tauv, tauw);
    else
        return gebrd(A, tauv, tauw, opts);
}
 
}  // namespace tlapack
 
#endif  // TLAPACK_BIDIAG_HH