matpackI.cc

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/* Copyright (C) 2001-2019 Stefan Buehler <sbuehler@ltu.se>

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any
   later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA. */

#include "matpackI.h"
#include <cmath>
#include <cstring>
#include "blas.h"
#include "exceptions.h"

using std::cout;
using std::endl;
using std::runtime_error;
using std::setw;

// Define the global joker object:
extern const Joker joker = Joker();

static const Numeric RAD2DEG = 57.295779513082323;

std::ostream& operator<<(std::ostream& os, const Range& r) {
  os << "Range(" << r.get_start() << ", " << r.get_extent() << ", "
     << r.get_stride() << ")";
  return os;
}

// Functions for ConstVectorView:
// ------------------------------

bool ConstVectorView::empty() const { return (nelem() == 0); }

Index ConstVectorView::nelem() const { return mrange.mextent; }

Numeric ConstVectorView::sum() const {
  Numeric s = 0;
  ConstIterator1D i = begin();
  const ConstIterator1D e = end();

  for (; i != e; ++i) s += *i;

  return s;
}

ConstVectorView ConstVectorView::operator[](const Range& r) const {
  return ConstVectorView(mdata, mrange, r);
}

ConstIterator1D ConstVectorView::begin() const {
  return ConstIterator1D(mdata + mrange.mstart, mrange.mstride);
}

ConstIterator1D ConstVectorView::end() const {
  return ConstIterator1D(
      mdata + mrange.mstart + (mrange.mextent) * mrange.mstride,
      mrange.mstride);
}

ConstVectorView::operator ConstMatrixView() const {
  // The old version (before 2013-01-18) of this was:
  //    return ConstMatrixView(mdata,mrange,Range(mrange.mstart,1));
  // Bus this was a bug! The problem is that the matrix index operator adds
  // the mstart from both row and columm range object to mdata

  return ConstMatrixView(mdata, mrange, Range(0, 1));
}

/* This one is a bit tricky: We have to cast away the arguments const
   qualifier, because mdata is not const. This should be safe, since
   there are no non-const methods for ConstVectorView. */
ConstVectorView::ConstVectorView(const Numeric& a)
    : mrange(0, 1), mdata(&const_cast<Numeric&>(a)) {
  // Nothing to do here.
}

ConstVectorView::ConstVectorView(Numeric* data, const Range& range)
    : mrange(range), mdata(data) {
  // Nothing to do here.
}

ConstVectorView::ConstVectorView(Numeric* data, const Range& p, const Range& n)
    : mrange(p, n), mdata(data) {
  // Nothing to do here.
}

/* Output operator. This demonstrates how iterators can be used to
   traverse the vector. The iterators know which part of the vector
   is `active', and also the stride. */
std::ostream& operator<<(std::ostream& os, const ConstVectorView& v) {
  ConstIterator1D i = v.begin();
  const ConstIterator1D end = v.end();

  if (i != end) {
    os << setw(3) << *i;
    ++i;
  }
  for (; i != end; ++i) {
    os << " " << setw(3) << *i;
  }

  return os;
}

// Functions for VectorView:
// ------------------------

VectorView::VectorView(const Vector&) {
  throw runtime_error(
      "Creating a VectorView from a const Vector is not allowed.");
  // This is not really a runtime error, but I don't want to start
  // producing direct output from inside matpack. And just exiting is
  // not so nice.
  // If you see this error, there is a bug in the code, not in the
  // ARTS input.
}

VectorView::VectorView(Vector& v) {
  mdata = v.mdata;
  mrange = v.mrange;
}

VectorView VectorView::operator[](const Range& r) {
  return VectorView(mdata, mrange, r);
}

Iterator1D VectorView::begin() {
  return Iterator1D(mdata + mrange.mstart, mrange.mstride);
}

Iterator1D VectorView::end() {
  return Iterator1D(mdata + mrange.mstart + (mrange.mextent) * mrange.mstride,
                    mrange.mstride);
}

VectorView& VectorView::operator=(const ConstVectorView& v) {
  //  cout << "Assigning VectorView from ConstVectorView.\n";

  // Check that sizes are compatible:
  assert(mrange.mextent == v.mrange.mextent);

  copy(v.begin(), v.end(), begin());

  return *this;
}

VectorView& VectorView::operator=(const VectorView& v) {
  //  cout << "Assigning VectorView from VectorView.\n";

  // Check that sizes are compatible:
  assert(mrange.mextent == v.mrange.mextent);

  copy(v.begin(), v.end(), begin());

  return *this;
}

VectorView& VectorView::operator=(const Vector& v) {
  //  cout << "Assigning VectorView from Vector.\n";

  // Check that sizes are compatible:
  assert(mrange.mextent == v.mrange.mextent);

  copy(v.begin(), v.end(), begin());

  return *this;
}

VectorView& VectorView::operator=(Numeric x) {
  copy(x, begin(), end());
  return *this;
}

VectorView VectorView::operator*=(Numeric x) {
  const Iterator1D e = end();
  for (Iterator1D i = begin(); i != e; ++i) *i *= x;
  return *this;
}

VectorView VectorView::operator/=(Numeric x) {
  const Iterator1D e = end();
  for (Iterator1D i = begin(); i != e; ++i) *i /= x;
  return *this;
}

VectorView VectorView::operator+=(Numeric x) {
  const Iterator1D e = end();
  for (Iterator1D i = begin(); i != e; ++i) *i += x;
  return *this;
}

VectorView VectorView::operator-=(Numeric x) {
  const Iterator1D e = end();
  for (Iterator1D i = begin(); i != e; ++i) *i -= x;
  return *this;
}

VectorView VectorView::operator*=(const ConstVectorView& x) {
  assert(nelem() == x.nelem());

  ConstIterator1D s = x.begin();

  Iterator1D i = begin();
  const Iterator1D e = end();

  for (; i != e; ++i, ++s) *i *= *s;
  return *this;
}

VectorView VectorView::operator/=(const ConstVectorView& x) {
  assert(nelem() == x.nelem());

  ConstIterator1D s = x.begin();

  Iterator1D i = begin();
  const Iterator1D e = end();

  for (; i != e; ++i, ++s) *i /= *s;
  return *this;
}

VectorView VectorView::operator+=(const ConstVectorView& x) {
  assert(nelem() == x.nelem());

  ConstIterator1D s = x.begin();

  Iterator1D i = begin();
  const Iterator1D e = end();

  for (; i != e; ++i, ++s) *i += *s;
  return *this;
}

VectorView VectorView::operator-=(const ConstVectorView& x) {
  assert(nelem() == x.nelem());

  ConstIterator1D s = x.begin();

  Iterator1D i = begin();
  const Iterator1D e = end();

  for (; i != e; ++i, ++s) *i -= *s;
  return *this;
}

VectorView::operator MatrixView() {
  // The old version (before 2013-01-18) of this was:
  //    return ConstMatrixView(mdata,mrange,Range(mrange.mstart,1));
  // Bus this was a bug! The problem is that the matrix index operator adds
  // the mstart from both row and columm range object to mdata

  return MatrixView(mdata, mrange, Range(0, 1));
}

const Numeric* VectorView::get_c_array() const {
  if (mrange.mstart != 0 || mrange.mstride != 1)
    throw std::runtime_error(
        "A VectorView can only be converted to a plain C-array if it's pointing to a continuous block of data");

  return mdata;
}

Numeric* VectorView::get_c_array() {
  if (mrange.mstart != 0 || mrange.mstride != 1)
    throw std::runtime_error(
        "A VectorView can only be converted to a plain C-array if it's pointing to a continuous block of data");

  return mdata;
}

VectorView::VectorView(Numeric& a) : ConstVectorView(a) {
  // Nothing to do here.
}

VectorView::VectorView(Numeric* data, const Range& range)
    : ConstVectorView(data, range) {
  // Nothing to do here.
}

VectorView::VectorView(Numeric* data, const Range& p, const Range& n)
    : ConstVectorView(data, p, n) {
  // Nothing to do here.
}

void copy(ConstIterator1D origin,
          const ConstIterator1D& end,
          Iterator1D target) {
  if (origin.mstride == 1 && target.mstride == 1)
    memcpy((void*)target.mx,
           (void*)origin.mx,
           sizeof(Numeric) * (end.mx - origin.mx));
  else
    for (; origin != end; ++origin, ++target) *target = *origin;
}

void copy(Numeric x, Iterator1D target, const Iterator1D& end) {
  for (; target != end; ++target) *target = x;
}

// Functions for Vector:
// ---------------------

Vector::Vector(std::initializer_list<Numeric> init)
    : VectorView(new Numeric[init.size()], Range(0, init.size())) {
  std::copy(init.begin(), init.end(), begin());
}

Vector::Vector(Index n) : VectorView(new Numeric[n], Range(0, n)) {
  // Nothing to do here.
}

Vector::Vector(Index n, Numeric fill)
    : VectorView(new Numeric[n], Range(0, n)) {
  // Here we can access the raw memory directly, for slightly
  // increased efficiency:
  std::fill_n(mdata, n, fill);
}

Vector::Vector(Numeric start, Index extent, Numeric stride)
    : VectorView(new Numeric[extent], Range(0, extent)) {
  // Fill with values:
  Numeric x = start;
  Iterator1D i = begin();
  const Iterator1D e = end();
  for (; i != e; ++i) {
    *i = x;
    x += stride;
  }
}

Vector::Vector(const ConstVectorView& v)
    : VectorView(new Numeric[v.nelem()], Range(0, v.nelem())) {
  copy(v.begin(), v.end(), begin());
}

Vector::Vector(const Vector& v)
    : VectorView(new Numeric[v.nelem()], Range(0, v.nelem())) {
  std::memcpy(mdata, v.mdata, nelem() * sizeof(Numeric));
}

Vector::Vector(const std::vector<Numeric>& v)
    : VectorView(new Numeric[v.size()], Range(0, v.size())) {
  std::vector<Numeric>::const_iterator vec_it_end = v.end();
  Iterator1D this_it = this->begin();
  for (std::vector<Numeric>::const_iterator vec_it = v.begin();
       vec_it != vec_it_end;
       ++vec_it, ++this_it)
    *this_it = *vec_it;
}

Vector& Vector::operator=(std::initializer_list<Numeric> v) {
  resize(v.size());
  std::copy(v.begin(), v.end(), begin());
  return *this;
}

Vector& Vector::operator=(const Vector& v) {
  if (this != &v) {
    resize(v.nelem());
    std::memcpy(mdata, v.mdata, nelem() * sizeof(Numeric));
  }
  return *this;
}

Vector& Vector::operator=(Vector&& v) noexcept {
  if (this != &v) {
    delete[] mdata;
    mdata = v.mdata;
    mrange = v.mrange;
    v.mrange = Range(0, 0);
    v.mdata = nullptr;
  }
  return *this;
}

Vector& Vector::operator=(const Array<Numeric>& x) {
  resize(x.nelem());
  VectorView::operator=(x);
  return *this;
}

Vector& Vector::operator=(Numeric x) {
  std::fill_n(mdata, nelem(), x);
  return *this;
}

void Vector::resize(Index n) {
  assert(0 <= n);
  if (mrange.mextent != n) {
    delete[] mdata;
    mdata = new Numeric[n];
    mrange.mstart = 0;
    mrange.mextent = n;
    mrange.mstride = 1;
  }
}

void swap(Vector& v1, Vector& v2) {
  std::swap(v1.mrange, v2.mrange);
  std::swap(v1.mdata, v2.mdata);
}

Vector::~Vector() { delete[] mdata; }

// Functions for ConstMatrixView:
// ------------------------------

bool ConstMatrixView::empty() const { return (nrows() == 0 || ncols() == 0); }

Index ConstMatrixView::nrows() const { return mrr.mextent; }

Index ConstMatrixView::ncols() const { return mcr.mextent; }

ConstMatrixView ConstMatrixView::operator()(const Range& r,
                                            const Range& c) const {
  return ConstMatrixView(mdata, mrr, mcr, r, c);
}

ConstVectorView ConstMatrixView::operator()(const Range& r, Index c) const {
  // Check that c is valid:
  assert(0 <= c);
  assert(c < mcr.mextent);

  return ConstVectorView(mdata + mcr.mstart + c * mcr.mstride, mrr, r);
}

ConstVectorView ConstMatrixView::operator()(Index r, const Range& c) const {
  // Check that r is valid:
  assert(0 <= r);
  assert(r < mrr.mextent);

  return ConstVectorView(mdata + mrr.mstart + r * mrr.mstride, mcr, c);
}

ConstIterator2D ConstMatrixView::begin() const {
  return ConstIterator2D(ConstVectorView(mdata + mrr.mstart, mcr), mrr.mstride);
}

ConstIterator2D ConstMatrixView::end() const {
  return ConstIterator2D(
      ConstVectorView(mdata + mrr.mstart + (mrr.mextent) * mrr.mstride, mcr),
      mrr.mstride);
}


ConstVectorView ConstMatrixView::diagonal() const {
  Index n = std::min(mrr.mextent, mcr.mextent);
  return ConstVectorView(mdata + mrr.mstart + mcr.mstart,
                         Range(0, n, mrr.mstride + mcr.mstride));
}

ConstMatrixView::ConstMatrixView(Numeric* data,
                                 const Range& rr,
                                 const Range& cr)
    : mrr(rr), mcr(cr), mdata(data) {
  // Nothing to do here.
}

ConstMatrixView::ConstMatrixView(Numeric* data,
                                 const Range& pr,
                                 const Range& pc,
                                 const Range& nr,
                                 const Range& nc)
    : mrr(pr, nr), mcr(pc, nc), mdata(data) {
  // Nothing to do here.
}

std::ostream& operator<<(std::ostream& os, const ConstMatrixView& v) {
  // Row iterators:
  ConstIterator2D ir = v.begin();
  const ConstIterator2D end_row = v.end();

  if (ir != end_row) {
    ConstIterator1D ic = ir->begin();
    const ConstIterator1D end_col = ir->end();

    if (ic != end_col) {
      os << setw(3) << *ic;
      ++ic;
    }
    for (; ic != end_col; ++ic) {
      os << " " << setw(3) << *ic;
    }
    ++ir;
  }
  for (; ir != end_row; ++ir) {
    ConstIterator1D ic = ir->begin();
    const ConstIterator1D end_col = ir->end();

    os << "\n";
    if (ic != end_col) {
      os << setw(3) << *ic;
      ++ic;
    }
    for (; ic != end_col; ++ic) {
      os << " " << setw(3) << *ic;
    }
  }

  return os;
}

// Functions for MatrixView:
// -------------------------

MatrixView MatrixView::operator()(const Range& r, const Range& c) {
  return MatrixView(mdata, mrr, mcr, r, c);
}

VectorView MatrixView::operator()(const Range& r, Index c) {
  // Check that c is valid:
  assert(0 <= c);
  assert(c < mcr.mextent);

  return VectorView(mdata + mcr.mstart + c * mcr.mstride, mrr, r);
}

VectorView MatrixView::operator()(Index r, const Range& c) {
  // Check that r is valid:
  assert(0 <= r);
  assert(r < mrr.mextent);

  return VectorView(mdata + mrr.mstart + r * mrr.mstride, mcr, c);
}

//    hiden by the non-const operator of the derived class.*/
//ConstIterator2D MatrixView::begin() const
//{
//  return ConstMatrixView::begin();
//}
//
//ConstIterator2D MatrixView::end() const
//{
//  return ConstMatrixView::end();
//}

Iterator2D MatrixView::begin() {
  return Iterator2D(VectorView(mdata + mrr.mstart, mcr), mrr.mstride);
}

Iterator2D MatrixView::end() {
  return Iterator2D(
      VectorView(mdata + mrr.mstart + (mrr.mextent) * mrr.mstride, mcr),
      mrr.mstride);
}

MatrixView& MatrixView::operator=(const ConstMatrixView& m) {
  // Check that sizes are compatible:
  assert(mrr.mextent == m.mrr.mextent);
  assert(mcr.mextent == m.mcr.mextent);

  copy(m.begin(), m.end(), begin());
  return *this;
}

MatrixView& MatrixView::operator=(const MatrixView& m) {
  // Check that sizes are compatible:
  assert(mrr.mextent == m.mrr.mextent);
  assert(mcr.mextent == m.mcr.mextent);

  copy(m.begin(), m.end(), begin());
  return *this;
}

MatrixView& MatrixView::operator=(const Matrix& m) {
  // Check that sizes are compatible:
  assert(mrr.mextent == m.mrr.mextent);
  assert(mcr.mextent == m.mcr.mextent);

  copy(m.begin(), m.end(), begin());
  return *this;
}

MatrixView& MatrixView::operator=(const ConstVectorView& v) {
  // Check that sizes are compatible:
  assert(mrr.mextent == v.nelem());
  assert(mcr.mextent == 1);
  //  dummy = ConstMatrixView(v.mdata,v.mrange,Range(v.mrange.mstart,1));;
  ConstMatrixView dummy(v);
  copy(dummy.begin(), dummy.end(), begin());
  return *this;
}

MatrixView& MatrixView::operator=(Numeric x) {
  copy(x, begin(), end());
  return *this;
}

MatrixView& MatrixView::operator*=(Numeric x) {
  const Iterator2D er = end();
  for (Iterator2D r = begin(); r != er; ++r) {
    const Iterator1D ec = r->end();
    for (Iterator1D c = r->begin(); c != ec; ++c) *c *= x;
  }
  return *this;
}

MatrixView& MatrixView::operator/=(Numeric x) {
  const Iterator2D er = end();
  for (Iterator2D r = begin(); r != er; ++r) {
    const Iterator1D ec = r->end();
    for (Iterator1D c = r->begin(); c != ec; ++c) *c /= x;
  }
  return *this;
}

MatrixView& MatrixView::operator+=(Numeric x) {
  const Iterator2D er = end();
  for (Iterator2D r = begin(); r != er; ++r) {
    const Iterator1D ec = r->end();
    for (Iterator1D c = r->begin(); c != ec; ++c) *c += x;
  }
  return *this;
}

MatrixView& MatrixView::operator-=(Numeric x) {
  const Iterator2D er = end();
  for (Iterator2D r = begin(); r != er; ++r) {
    const Iterator1D ec = r->end();
    for (Iterator1D c = r->begin(); c != ec; ++c) *c -= x;
  }
  return *this;
}

const Numeric* MatrixView::get_c_array() const {
  if (mrr.mstart != 0 || mrr.mstride != mcr.mextent || mcr.mstart != 0 ||
      mcr.mstride != 1)
    throw std::runtime_error(
        "A MatrixView can only be converted to a plain C-array if it's pointing to a continuous block of data");

  return mdata;
}

Numeric* MatrixView::get_c_array() {
  if (mrr.mstart != 0 || mrr.mstride != mcr.mextent || mcr.mstart != 0 ||
      mcr.mstride != 1)
    throw std::runtime_error(
        "A MatrixView can only be converted to a plain C-array if it's pointing to a continuous block of data");

  return mdata;
}

MatrixView& MatrixView::operator*=(const ConstMatrixView& x) {
  assert(nrows() == x.nrows());
  assert(ncols() == x.ncols());
  ConstIterator2D sr = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sr) {
    ConstIterator1D sc = sr->begin();
    Iterator1D c = r->begin();
    const Iterator1D ec = r->end();
    for (; c != ec; ++c, ++sc) *c *= *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator/=(const ConstMatrixView& x) {
  assert(nrows() == x.nrows());
  assert(ncols() == x.ncols());
  ConstIterator2D sr = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sr) {
    ConstIterator1D sc = sr->begin();
    Iterator1D c = r->begin();
    const Iterator1D ec = r->end();
    for (; c != ec; ++c, ++sc) *c /= *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator+=(const ConstMatrixView& x) {
  assert(nrows() == x.nrows());
  assert(ncols() == x.ncols());
  ConstIterator2D sr = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sr) {
    ConstIterator1D sc = sr->begin();
    Iterator1D c = r->begin();
    const Iterator1D ec = r->end();
    for (; c != ec; ++c, ++sc) *c += *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator-=(const ConstMatrixView& x) {
  assert(nrows() == x.nrows());
  assert(ncols() == x.ncols());
  ConstIterator2D sr = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sr) {
    ConstIterator1D sc = sr->begin();
    Iterator1D c = r->begin();
    const Iterator1D ec = r->end();
    for (; c != ec; ++c, ++sc) *c -= *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator*=(const ConstVectorView& x) {
  assert(nrows() == x.nelem());
  assert(ncols() == 1);
  ConstIterator1D sc = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sc) {
    Iterator1D c = r->begin();
    *c *= *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator/=(const ConstVectorView& x) {
  assert(nrows() == x.nelem());
  assert(ncols() == 1);
  ConstIterator1D sc = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sc) {
    Iterator1D c = r->begin();
    *c /= *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator+=(const ConstVectorView& x) {
  assert(nrows() == x.nelem());
  assert(ncols() == 1);
  ConstIterator1D sc = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sc) {
    Iterator1D c = r->begin();
    *c += *sc;
  }
  return *this;
}

MatrixView& MatrixView::operator-=(const ConstVectorView& x) {
  assert(nrows() == x.nelem());
  assert(ncols() == 1);
  ConstIterator1D sc = x.begin();
  Iterator2D r = begin();
  const Iterator2D er = end();
  for (; r != er; ++r, ++sc) {
    Iterator1D c = r->begin();
    *c -= *sc;
  }
  return *this;
}

MatrixView::MatrixView(Numeric* data, const Range& rr, const Range& cr)
    : ConstMatrixView(data, rr, cr) {
  // Nothing to do here.
}

MatrixView::MatrixView(Numeric* data,
                       const Range& pr,
                       const Range& pc,
                       const Range& nr,
                       const Range& nc)
    : ConstMatrixView(data, pr, pc, nr, nc) {
  // Nothing to do here.
}

void copy(ConstIterator2D origin,
          const ConstIterator2D& end,
          Iterator2D target) {
  for (; origin != end; ++origin, ++target) {
    ConstIterator1D o = origin->begin();
    const ConstIterator1D e = origin->end();
    Iterator1D t = target->begin();
    for (; o != e; ++o, ++t) *t = *o;
  }
}

void copy(Numeric x, Iterator2D target, const Iterator2D& end) {
  for (; target != end; ++target) {
    Iterator1D t = target->begin();
    const Iterator1D e = target->end();
    for (; t != e; ++t) *t = x;
  }
}

// Functions for Matrix:
// ---------------------

Matrix::Matrix(Index r, Index c)
    : MatrixView(new Numeric[r * c], Range(0, r, c), Range(0, c)) {
  // Nothing to do here.
}

Matrix::Matrix(Index r, Index c, Numeric fill)
    : MatrixView(new Numeric[r * c], Range(0, r, c), Range(0, c)) {
  // Here we can access the raw memory directly, for slightly
  // increased efficiency:
  std::fill_n(mdata, r * c, fill);
}

Matrix::Matrix(const ConstMatrixView& m)
    : MatrixView(new Numeric[m.nrows() * m.ncols()],
                 Range(0, m.nrows(), m.ncols()),
                 Range(0, m.ncols())) {
  copy(m.begin(), m.end(), begin());
}

Matrix::Matrix(const Matrix& m)
    : MatrixView(new Numeric[m.nrows() * m.ncols()],
                 Range(0, m.nrows(), m.ncols()),
                 Range(0, m.ncols())) {
  // There is a catch here: If m is an empty matrix, then it will have
  // 0 colunns. But this is used to initialize the stride of the row
  // Range! Thus, this method has to be consistent with the behaviour
  // of Range::Range. For now, Range::Range allows also stride 0.
  std::memcpy(mdata, m.mdata, nrows() * ncols() * sizeof(Numeric));
}


Matrix& Matrix::operator=(const Matrix& m) {
  if (this != &m) {
    resize(m.nrows(), m.ncols());
    std::memcpy(mdata, m.mdata, nrows() * ncols() * sizeof(Numeric));
  }
  return *this;
}

Matrix& Matrix::operator=(Matrix&& m) noexcept {
  if (this != &m) {
    delete[] mdata;
    mdata = m.mdata;
    mrr = m.mrr;
    mcr = m.mcr;
    m.mrr = Range(0, 0);
    m.mcr = Range(0, 0);
    m.mdata = nullptr;
  }
  return *this;
}

Matrix& Matrix::operator=(Numeric x) {
  std::fill_n(mdata, nrows() * ncols(), x);
  return *this;
}


Matrix& Matrix::operator=(const ConstVectorView& v) {
  resize(v.nelem(), 1);
  ConstMatrixView dummy(v);
  copy(dummy.begin(), dummy.end(), begin());
  return *this;
}

void Matrix::resize(Index r, Index c) {
  assert(0 <= r);
  assert(0 <= c);

  if (mrr.mextent != r || mcr.mextent != c) {
    delete[] mdata;
    mdata = new Numeric[r * c];

    mrr.mstart = 0;
    mrr.mextent = r;
    mrr.mstride = c;

    mcr.mstart = 0;
    mcr.mextent = c;
    mcr.mstride = 1;
  }
}

void swap(Matrix& m1, Matrix& m2) {
  std::swap(m1.mrr, m2.mrr);
  std::swap(m1.mcr, m2.mcr);
  std::swap(m1.mdata, m2.mdata);
}

Matrix::~Matrix() {
  //   cout << "Destroying a Matrix:\n"
  //        << *this << "\n........................................\n";
  delete[] mdata;
}

// Some general Matrix Vector functions:

Numeric operator*(const ConstVectorView& a, const ConstVectorView& b) {
  // Check dimensions:
  assert(a.nelem() == b.nelem());

  const ConstIterator1D ae = a.end();
  ConstIterator1D ai = a.begin();
  ConstIterator1D bi = b.begin();

  Numeric res = 0;
  for (; ai != ae; ++ai, ++bi) res += (*ai) * (*bi);

  return res;
}


void mult(VectorView y, const ConstMatrixView& M, const ConstVectorView& x) {
  assert(y.mrange.get_extent() == M.mrr.get_extent());
  assert(M.mcr.get_extent() == x.mrange.get_extent());
  assert((M.mcr.get_extent() != 0) && (M.mrr.get_extent() != 0));

  if ((M.mcr.get_stride() == 1) || (M.mrr.get_stride() == 1)) {
    char trans;
    int m, n;
    double zero = 0.0;
    double one = 1.0;
    int LDA, incx, incy;

    if (M.mcr.get_stride() != 1) {
      trans = 'n';
      m = (int)M.mrr.get_extent();
      n = (int)M.mcr.get_extent();
      LDA = (int)M.mcr.get_stride();
    } else {
      trans = 't';
      m = (int)M.mcr.get_extent();
      n = (int)M.mrr.get_extent();
      LDA = (int)M.mrr.get_stride();
      if (M.mrr.get_stride() == 1) LDA = m;
    }

    incx = (int)x.mrange.get_stride();
    incy = (int)y.mrange.get_stride();

    double* mstart = M.mdata + M.mcr.get_start() + M.mrr.get_start();
    double* ystart = y.mdata + y.mrange.get_start();
    double* xstart = x.mdata + x.mrange.get_start();

    dgemv_(&trans,
           &m,
           &n,
           &one,
           mstart,
           &LDA,
           xstart,
           &incx,
           &zero,
           ystart,
           &incy);

  } else {
    mult_general(y, M, x);
  }
}

void mult_general(VectorView y,
                  const ConstMatrixView& M,
                  const ConstVectorView& x) {
  // Check dimensions:
  assert(y.mrange.mextent == M.mrr.mextent);
  assert(M.mcr.mextent == x.mrange.mextent);
  assert(M.mcr.mextent != 0 && M.mrr.mextent != 0);

  // Let's first find the pointers to the starting positions
  Numeric* mdata = M.mdata + M.mcr.mstart + M.mrr.mstart;
  Numeric* xdata = x.mdata + x.mrange.mstart;
  Numeric* yelem = y.mdata + y.mrange.mstart;

  Index i = M.mrr.mextent;
  while (i--) {
    Numeric* melem = mdata;
    Numeric* xelem = xdata;  // Reset xelem to first element of source vector

    // Multiply first element of matrix row with first element of source
    // vector. This is done outside the loop to avoid initialization of the
    // target vector's element with zero (saves one assignment)
    *yelem = *melem * *xelem;

    Index j = M.mcr.mextent;  // --j (instead of j-- like in the outer loop)
    while (--j)               // is important here because we only want
    {                         // mextent-1 cycles
      melem += M.mcr.mstride;
      xelem += x.mrange.mstride;
      *yelem += *melem * *xelem;
    }

    mdata += M.mrr.mstride;     // Jump to next matrix row
    yelem += y.mrange.mstride;  // Jump to next element in target vector
  }
}


void mult(MatrixView A, const ConstMatrixView& B, const ConstMatrixView& C) {
  // Check dimensions:
  assert(A.nrows() == B.nrows());
  assert(A.ncols() == C.ncols());
  assert(B.ncols() == C.nrows());

  // Catch trivial case if one of the matrices is empty.
  if ((B.nrows() == 0) || (B.ncols() == 0) || (C.ncols() == 0)) return;

  // Matrices B and C must be continuous in at least on dimension,  C
  // must be continuous along the second dimension.
  if (((B.mrr.get_stride() == 1) || (B.mcr.get_stride() == 1)) &&
      ((C.mrr.get_stride() == 1) || (C.mcr.get_stride() == 1)) &&
      (A.mcr.get_stride() == 1)) {
    // BLAS uses column-major order while arts uses row-major order.
    // Hence instead of C = A * B we compute C^T = A^T * B^T!

    int k, m, n;

    k = (int)B.ncols();
    m = (int)C.ncols();
    n = (int)B.nrows();

    // Note also the clash in nomenclature: BLAS uses C = A * B while
    // arts uses A = B * C. Taking into accout this and the difference in
    // memory layouts, we need to map the MatrixViews A, B and C to the BLAS
    // arguments as follows:
    // A (arts) -> C (BLAS)
    // B (arts) -> B (BLAS)
    // C (arts) -> A (BLAS)

    // Char indicating whether A (BLAS) or B (BLAS) should be transposed.
    char transa, transb;
    // Sizes of the matrices along the direction in which they are
    // traversed.
    int lda, ldb, ldc;

    // Check if C (arts) is transposed.
    if (C.mrr.get_stride() == 1) {
      transa = 'T';
      lda = (int)C.mcr.get_stride();
    } else {
      transa = 'N';
      lda = (int)C.mrr.get_stride();
    }

    // Check if B (arts) is transposed.
    if (B.mrr.get_stride() == 1) {
      transb = 'T';
      ldb = (int)B.mcr.get_stride();
    } else {
      transb = 'N';
      ldb = (int)B.mrr.get_stride();
    }

    // In case B (arts) has only one column, column and row stride are 1.
    // We therefore need to set ldb to k, since dgemm_ requires lda to be at
    // least k / m if A is non-transposed / transposed.
    if ((B.mcr.get_stride() == 1) && (B.mrr.get_stride() == 1)) {
      transb = 'N';
      ldb = k;
    }

    // The same holds for C (arts).
    if ((C.mcr.get_stride() == 1) && (C.mrr.get_stride() == 1)) {
      transa = 'N';
      lda = m;
    }

    ldc = (int)A.mrr.get_stride();
    // The same holds for A (arts).
    if ((A.mcr.get_stride() == 1) && (A.mrr.get_stride() == 1)) {
      ldc = m;
    }
    double alpha = 1.0, beta = 0.0;

    dgemm_(&transa,
           &transb,
           &m,
           &n,
           &k,
           &alpha,
           C.mdata + C.mrr.get_start() + C.mcr.get_start(),
           &lda,
           B.mdata + B.mrr.get_start() + B.mcr.get_start(),
           &ldb,
           &beta,
           A.mdata + A.mrr.get_start() + A.mcr.get_start(),
           &ldc);

  } else {
    mult_general(A, B, C);
  }
}


void mult_general(MatrixView A,
                  const ConstMatrixView& B,
                  const ConstMatrixView& C) {
  // Check dimensions:
  assert(A.nrows() == B.nrows());
  assert(A.ncols() == C.ncols());
  assert(B.ncols() == C.nrows());

  // Let's get the transpose of C, so that we can use 2D iterators to
  // access the columns (= rows of the transpose).
  ConstMatrixView CT = transpose(C);

  const Iterator2D ae = A.end();
  Iterator2D ai = A.begin();
  ConstIterator2D bi = B.begin();

  // This walks through the rows of A and B:
  for (; ai != ae; ++ai, ++bi) {
    const Iterator1D ace = ai->end();
    Iterator1D aci = ai->begin();
    ConstIterator2D cti = CT.begin();

    // This walks through the columns of A with a 1D iterator, and
    // at the same time through the rows of CT, which are the columns of
    // C, with a 2D iterator:
    for (; aci != ace; ++aci, ++cti) {
      // The operator * is used to compute the scalar product
      // between rows of B and rows of C.transpose().
      *aci = (*bi) * (*cti);
    }
  }
}


void cross3(VectorView c, const ConstVectorView& a, const ConstVectorView& b) {
  assert(a.nelem() == 3);
  assert(b.nelem() == 3);
  assert(c.nelem() == 3);

  c[0] = a[1] * b[2] - a[2] * b[1];
  c[1] = a[2] * b[0] - a[0] * b[2];
  c[2] = a[0] * b[1] - a[1] * b[0];
}

Numeric vector_angle(ConstVectorView a, ConstVectorView b) {
  assert(a.nelem() == b.nelem());
  Numeric arg = (a * b) / sqrt(a * a) / sqrt(b * b);

  // Due to numerical inaccuracy, arg might be slightly larger than 1.
  // We catch those cases to avoid spurious returns of NaNs
  return fabs(arg) > 1. ? 0. : acos(arg) * RAD2DEG;
}

void proj(Vector& c, ConstVectorView a, ConstVectorView b) {
  assert(a.nelem() == b.nelem());
  assert(a.nelem() == c.nelem());

  const Numeric C = (a * b) / (a * a);
  c = a;
  c *= C;
};

ConstMatrixView transpose(ConstMatrixView m) {
  return ConstMatrixView(m.mdata, m.mcr, m.mrr);
}

MatrixView transpose(MatrixView m) { return MatrixView(m.mdata, m.mcr, m.mrr); }

MatrixView transpose(Vector v) { return transpose((MatrixView)v); }

void transform(VectorView y, double (&my_func)(double), ConstVectorView x) {
  // Check dimensions:
  assert(y.nelem() == x.nelem());

  const ConstIterator1D xe = x.end();
  ConstIterator1D xi = x.begin();
  Iterator1D yi = y.begin();
  for (; xi != xe; ++xi, ++yi) *yi = my_func(*xi);
}

void transform(MatrixView y, double (&my_func)(double), ConstMatrixView x) {
  // Check dimensions:
  assert(y.nrows() == x.nrows());
  assert(y.ncols() == x.ncols());

  const ConstIterator2D rxe = x.end();
  ConstIterator2D rx = x.begin();
  Iterator2D ry = y.begin();
  for (; rx != rxe; ++rx, ++ry) {
    const ConstIterator1D cxe = rx->end();
    ConstIterator1D cx = rx->begin();
    Iterator1D cy = ry->begin();
    for (; cx != cxe; ++cx, ++cy) *cy = my_func(*cx);
  }
}

Numeric max(const ConstVectorView& x) {
  // Initial value for max:
  Numeric max = x[0];

  const ConstIterator1D xe = x.end();
  ConstIterator1D xi = x.begin();

  for (; xi != xe; ++xi) {
    if (*xi > max) max = *xi;
  }

  return max;
}

Numeric max(const ConstMatrixView& x) {
  // Initial value for max:
  Numeric max = x(0, 0);

  const ConstIterator2D rxe = x.end();
  ConstIterator2D rx = x.begin();

  for (; rx != rxe; ++rx) {
    const ConstIterator1D cxe = rx->end();
    ConstIterator1D cx = rx->begin();

    for (; cx != cxe; ++cx)
      if (*cx > max) max = *cx;
  }

  return max;
}

Numeric min(const ConstVectorView& x) {
  // Initial value for min:
  Numeric min = x[0];

  const ConstIterator1D xe = x.end();
  ConstIterator1D xi = x.begin();

  for (; xi != xe; ++xi) {
    if (*xi < min) min = *xi;
  }

  return min;
}

Numeric min(const ConstMatrixView& x) {
  // Initial value for min:
  Numeric min = x(0, 0);

  const ConstIterator2D rxe = x.end();
  ConstIterator2D rx = x.begin();

  for (; rx != rxe; ++rx) {
    const ConstIterator1D cxe = rx->end();
    ConstIterator1D cx = rx->begin();

    for (; cx != cxe; ++cx)
      if (*cx < min) min = *cx;
  }

  return min;
}

Numeric mean(const ConstVectorView& x) {
  // Initial value for mean:
  Numeric mean = 0;

  const ConstIterator1D xe = x.end();
  ConstIterator1D xi = x.begin();

  for (; xi != xe; ++xi) mean += *xi;

  mean /= (Numeric)x.nelem();

  return mean;
}

Numeric mean(const ConstMatrixView& x) {
  // Initial value for mean:
  Numeric mean = 0;

  const ConstIterator2D rxe = x.end();
  ConstIterator2D rx = x.begin();

  for (; rx != rxe; ++rx) {
    const ConstIterator1D cxe = rx->end();
    ConstIterator1D cx = rx->begin();

    for (; cx != cxe; ++cx) mean += *cx;
  }

  mean /= (Numeric)(x.nrows() * x.ncols());

  return mean;
}

VectorView& VectorView::operator=(const Array<Numeric>& v) {
  //  cout << "Assigning VectorView from Array<Numeric>.\n";

  // Check that sizes are compatible:
  assert(mrange.mextent == v.nelem());

  // Iterators for Array:
  Array<Numeric>::const_iterator i = v.begin();
  const Array<Numeric>::const_iterator e = v.end();
  // Iterator for Vector:
  Iterator1D target = begin();

  for (; i != e; ++i, ++target) *target = *i;

  return *this;
}

// Const

// Converts constant matrix to constant eigen map
ConstMatrixViewMap MapToEigen(const ConstMatrixView& A) {
  return ConstMatrixViewMap(A.mdata + A.mrr.get_start() + A.mcr.get_start(),
                            A.nrows(),
                            A.ncols(),
                            StrideType(A.mrr.get_stride(), A.mcr.get_stride()));
}

// Converts constant vector to constant eigen row-view
ConstMatrixViewMap MapToEigen(const ConstVectorView& A) {
  return ConstMatrixViewMap(A.mdata + A.mrange.get_start(),
                            A.nelem(),
                            1,
                            StrideType(A.mrange.get_stride(), 1));
}

// Converts constant vector to constant eigen row-view
ConstMatrixViewMap MapToEigenRow(const ConstVectorView& A) {
  return MapToEigen(A);
}

// Converts constant vector to constant eigen column-view
ConstMatrixViewMap MapToEigenCol(const ConstVectorView& A) {
  return ConstMatrixViewMap(A.mdata + A.mrange.get_start(),
                            1,
                            A.nelem(),
                            StrideType(1, A.mrange.get_stride()));
}

// Non- const

// Converts matrix to eigen map
MatrixViewMap MapToEigen(MatrixView& A) {
  return MatrixViewMap(A.mdata + A.mrr.get_start() + A.mcr.get_start(),
                       A.nrows(),
                       A.ncols(),
                       StrideType(A.mrr.get_stride(), A.mcr.get_stride()));
}

// Converts vector to eigen map row-view
MatrixViewMap MapToEigen(VectorView& A) {
  return MatrixViewMap(A.mdata + A.mrange.get_start(),
                       A.nelem(),
                       1,
                       StrideType(A.mrange.get_stride(), 1));
}

// Converts vector to eigen map row-view
MatrixViewMap MapToEigenRow(VectorView& A) { return MapToEigen(A); }

// Converts vector to eigen map column-view
MatrixViewMap MapToEigenCol(VectorView& A) {
  return MatrixViewMap(A.mdata + A.mrange.get_start(),
                       1,
                       A.nelem(),
                       StrideType(1, A.mrange.get_stride()));
}

// Special 4x4

// Converts matrix to eigen map
Matrix4x4ViewMap MapToEigen4x4(MatrixView& A) {
  return Matrix4x4ViewMap(A.mdata + A.mrr.get_start() + A.mcr.get_start(),
                          4,
                          4,
                          StrideType(A.mrr.get_stride(), A.mcr.get_stride()));
}

// Converts constant matrix to constant eigen map
ConstMatrix4x4ViewMap MapToEigen4x4(const ConstMatrixView& A) {
  return ConstMatrix4x4ViewMap(
      A.mdata + A.mrr.get_start() + A.mcr.get_start(),
      4,
      4,
      StrideType(A.mrr.get_stride(), A.mcr.get_stride()));
}

// Helper function for debugging
#ifndef NDEBUG

Numeric debug_matrixview_get_elem(MatrixView& mv, Index r, Index c) {
  return mv(r, c);
}

#endif