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armadillo-code/include/armadillo_bits/gmm_full_meat.hpp
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// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------
//! \addtogroup gmm_full
//! @{
namespace gmm_priv
{
template<typename eT>
inline
gmm_full<eT>::~gmm_full()
{
arma_extra_debug_sigprint_this(this);
arma_type_check(( (is_same_type<eT,float>::value == false) && (is_same_type<eT,double>::value == false) ));
}
template<typename eT>
inline
gmm_full<eT>::gmm_full()
{
arma_extra_debug_sigprint_this(this);
}
template<typename eT>
inline
gmm_full<eT>::gmm_full(const gmm_full<eT>& x)
{
arma_extra_debug_sigprint_this(this);
init(x);
}
template<typename eT>
inline
gmm_full<eT>&
gmm_full<eT>::operator=(const gmm_full<eT>& x)
{
arma_extra_debug_sigprint();
init(x);
return *this;
}
template<typename eT>
inline
gmm_full<eT>::gmm_full(const gmm_diag<eT>& x)
{
arma_extra_debug_sigprint_this(this);
init(x);
}
template<typename eT>
inline
gmm_full<eT>&
gmm_full<eT>::operator=(const gmm_diag<eT>& x)
{
arma_extra_debug_sigprint();
init(x);
return *this;
}
template<typename eT>
inline
gmm_full<eT>::gmm_full(const uword in_n_dims, const uword in_n_gaus)
{
arma_extra_debug_sigprint_this(this);
init(in_n_dims, in_n_gaus);
}
template<typename eT>
inline
void
gmm_full<eT>::reset()
{
arma_extra_debug_sigprint();
init(0, 0);
}
template<typename eT>
inline
void
gmm_full<eT>::reset(const uword in_n_dims, const uword in_n_gaus)
{
arma_extra_debug_sigprint();
init(in_n_dims, in_n_gaus);
}
template<typename eT>
template<typename T1, typename T2, typename T3>
inline
void
gmm_full<eT>::set_params(const Base<eT,T1>& in_means_expr, const BaseCube<eT,T2>& in_fcovs_expr, const Base<eT,T3>& in_hefts_expr)
{
arma_extra_debug_sigprint();
const unwrap <T1> tmp1(in_means_expr.get_ref());
const unwrap_cube<T2> tmp2(in_fcovs_expr.get_ref());
const unwrap <T3> tmp3(in_hefts_expr.get_ref());
const Mat <eT>& in_means = tmp1.M;
const Cube<eT>& in_fcovs = tmp2.M;
const Mat <eT>& in_hefts = tmp3.M;
arma_debug_check
(
(in_means.n_cols != in_fcovs.n_slices) || (in_means.n_rows != in_fcovs.n_rows) || (in_fcovs.n_rows != in_fcovs.n_cols) || (in_hefts.n_cols != in_means.n_cols) || (in_hefts.n_rows != 1),
"gmm_full::set_params(): given parameters have inconsistent and/or wrong sizes"
);
arma_debug_check( (in_means.is_finite() == false), "gmm_full::set_params(): given means have non-finite values" );
arma_debug_check( (in_fcovs.is_finite() == false), "gmm_full::set_params(): given fcovs have non-finite values" );
arma_debug_check( (in_hefts.is_finite() == false), "gmm_full::set_params(): given hefts have non-finite values" );
for(uword g=0; g < in_fcovs.n_slices; ++g)
{
arma_debug_check( (any(diagvec(in_fcovs.slice(g)) <= eT(0))), "gmm_full::set_params(): given fcovs have negative or zero values on diagonals" );
}
arma_debug_check( (any(vectorise(in_hefts) < eT(0))), "gmm_full::set_params(): given hefts have negative values" );
const eT s = accu(in_hefts);
arma_debug_check( ((s < (eT(1) - eT(0.001))) || (s > (eT(1) + eT(0.001)))), "gmm_full::set_params(): sum of given hefts is not 1" );
access::rw(means) = in_means;
access::rw(fcovs) = in_fcovs;
access::rw(hefts) = in_hefts;
init_constants();
}
template<typename eT>
template<typename T1>
inline
void
gmm_full<eT>::set_means(const Base<eT,T1>& in_means_expr)
{
arma_extra_debug_sigprint();
const unwrap<T1> tmp(in_means_expr.get_ref());
const Mat<eT>& in_means = tmp.M;
arma_debug_check( (arma::size(in_means) != arma::size(means)), "gmm_full::set_means(): given means have incompatible size" );
arma_debug_check( (in_means.is_finite() == false), "gmm_full::set_means(): given means have non-finite values" );
access::rw(means) = in_means;
}
template<typename eT>
template<typename T1>
inline
void
gmm_full<eT>::set_fcovs(const BaseCube<eT,T1>& in_fcovs_expr)
{
arma_extra_debug_sigprint();
const unwrap_cube<T1> tmp(in_fcovs_expr.get_ref());
const Cube<eT>& in_fcovs = tmp.M;
arma_debug_check( (arma::size(in_fcovs) != arma::size(fcovs)), "gmm_full::set_fcovs(): given fcovs have incompatible size" );
arma_debug_check( (in_fcovs.is_finite() == false), "gmm_full::set_fcovs(): given fcovs have non-finite values" );
for(uword i=0; i < in_fcovs.n_slices; ++i)
{
arma_debug_check( (any(diagvec(in_fcovs.slice(i)) <= eT(0))), "gmm_full::set_fcovs(): given fcovs have negative or zero values on diagonals" );
}
access::rw(fcovs) = in_fcovs;
init_constants();
}
template<typename eT>
template<typename T1>
inline
void
gmm_full<eT>::set_hefts(const Base<eT,T1>& in_hefts_expr)
{
arma_extra_debug_sigprint();
const unwrap<T1> tmp(in_hefts_expr.get_ref());
const Mat<eT>& in_hefts = tmp.M;
arma_debug_check( (arma::size(in_hefts) != arma::size(hefts)), "gmm_full::set_hefts(): given hefts have incompatible size" );
arma_debug_check( (in_hefts.is_finite() == false), "gmm_full::set_hefts(): given hefts have non-finite values" );
arma_debug_check( (any(vectorise(in_hefts) < eT(0))), "gmm_full::set_hefts(): given hefts have negative values" );
const eT s = accu(in_hefts);
arma_debug_check( ((s < (eT(1) - eT(0.001))) || (s > (eT(1) + eT(0.001)))), "gmm_full::set_hefts(): sum of given hefts is not 1" );
// make sure all hefts are positive and non-zero
const eT* in_hefts_mem = in_hefts.memptr();
eT* hefts_mem = access::rw(hefts).memptr();
for(uword i=0; i < hefts.n_elem; ++i)
{
hefts_mem[i] = (std::max)( in_hefts_mem[i], std::numeric_limits<eT>::min() );
}
access::rw(hefts) /= accu(hefts);
log_hefts = log(hefts);
}
template<typename eT>
inline
uword
gmm_full<eT>::n_dims() const
{
return means.n_rows;
}
template<typename eT>
inline
uword
gmm_full<eT>::n_gaus() const
{
return means.n_cols;
}
template<typename eT>
inline
bool
gmm_full<eT>::load(const std::string name)
{
arma_extra_debug_sigprint();
field< Mat<eT> > storage;
bool status = storage.load(name, arma_binary);
if( (status == false) || (storage.n_elem < 2) )
{
reset();
arma_debug_warn("gmm_full::load(): problem with loading or incompatible format");
return false;
}
uword count = 0;
const Mat<eT>& storage_means = storage(count); ++count;
const Mat<eT>& storage_hefts = storage(count); ++count;
const uword N_dims = storage_means.n_rows;
const uword N_gaus = storage_means.n_cols;
if( (storage.n_elem != (N_gaus + 2)) || (storage_hefts.n_rows != 1) || (storage_hefts.n_cols != N_gaus) )
{
reset();
arma_debug_warn("gmm_full::load(): incompatible format");
return false;
}
reset(N_dims, N_gaus);
access::rw(means) = storage_means;
access::rw(hefts) = storage_hefts;
for(uword g=0; g < N_gaus; ++g)
{
const Mat<eT>& storage_fcov = storage(count); ++count;
if( (storage_fcov.n_rows != N_dims) || (storage_fcov.n_cols != N_dims) )
{
reset();
arma_debug_warn("gmm_full::load(): incompatible format");
return false;
}
access::rw(fcovs).slice(g) = storage_fcov;
}
init_constants();
return true;
}
template<typename eT>
inline
bool
gmm_full<eT>::save(const std::string name) const
{
arma_extra_debug_sigprint();
const uword N_gaus = means.n_cols;
field< Mat<eT> > storage(2 + N_gaus);
uword count = 0;
storage(count) = means; ++count;
storage(count) = hefts; ++count;
for(uword g=0; g < N_gaus; ++g)
{
storage(count) = fcovs.slice(g); ++count;
}
const bool status = storage.save(name, arma_binary);
return status;
}
template<typename eT>
inline
Col<eT>
gmm_full<eT>::generate() const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
Col<eT> out( (N_gaus > 0) ? N_dims : uword(0) );
Col<eT> tmp( (N_gaus > 0) ? N_dims : uword(0), fill::randn );
if(N_gaus > 0)
{
const double val = randu<double>();
double csum = double(0);
uword gaus_id = 0;
for(uword j=0; j < N_gaus; ++j)
{
csum += hefts[j];
if(val <= csum) { gaus_id = j; break; }
}
out = chol_fcovs.slice(gaus_id) * tmp;
out += means.col(gaus_id);
}
return out;
}
template<typename eT>
inline
Mat<eT>
gmm_full<eT>::generate(const uword N_vec) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
Mat<eT> out( ( (N_gaus > 0) ? N_dims : uword(0) ), N_vec );
Mat<eT> tmp( ( (N_gaus > 0) ? N_dims : uword(0) ), N_vec, fill::randn );
if(N_gaus > 0)
{
const eT* hefts_mem = hefts.memptr();
for(uword i=0; i < N_vec; ++i)
{
const double val = randu<double>();
double csum = double(0);
uword gaus_id = 0;
for(uword j=0; j < N_gaus; ++j)
{
csum += hefts_mem[j];
if(val <= csum) { gaus_id = j; break; }
}
Col<eT> out_vec(out.colptr(i), N_dims, false, true);
Col<eT> tmp_vec(tmp.colptr(i), N_dims, false, true);
out_vec = chol_fcovs.slice(gaus_id) * tmp_vec;
out_vec += means.col(gaus_id);
}
}
return out;
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::log_p(const T1& expr, const gmm_empty_arg& junk1, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == true))>::result* junk2) const
{
arma_extra_debug_sigprint();
arma_ignore(junk1);
arma_ignore(junk2);
const uword N_dims = means.n_rows;
const quasi_unwrap<T1> U(expr);
arma_debug_check( (U.M.n_rows != N_dims), "gmm_full::log_p(): incompatible dimensions" );
return internal_scalar_log_p( U.M.memptr() );
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::log_p(const T1& expr, const uword gaus_id, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == true))>::result* junk2) const
{
arma_extra_debug_sigprint();
arma_ignore(junk2);
const uword N_dims = means.n_rows;
const quasi_unwrap<T1> U(expr);
arma_debug_check( (U.M.n_rows != N_dims), "gmm_full::log_p(): incompatible dimensions" );
arma_debug_check( (gaus_id >= means.n_cols), "gmm_full::log_p(): specified gaussian is out of range" );
return internal_scalar_log_p( U.M.memptr(), gaus_id );
}
template<typename eT>
template<typename T1>
inline
Row<eT>
gmm_full<eT>::log_p(const T1& expr, const gmm_empty_arg& junk1, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == false))>::result* junk2) const
{
arma_extra_debug_sigprint();
arma_ignore(junk1);
arma_ignore(junk2);
const quasi_unwrap<T1> tmp(expr);
const Mat<eT>& X = tmp.M;
return internal_vec_log_p(X);
}
template<typename eT>
template<typename T1>
inline
Row<eT>
gmm_full<eT>::log_p(const T1& expr, const uword gaus_id, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == false))>::result* junk2) const
{
arma_extra_debug_sigprint();
arma_ignore(junk2);
const quasi_unwrap<T1> tmp(expr);
const Mat<eT>& X = tmp.M;
return internal_vec_log_p(X, gaus_id);
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::sum_log_p(const Base<eT,T1>& expr) const
{
arma_extra_debug_sigprint();
const quasi_unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
return internal_sum_log_p(X);
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::sum_log_p(const Base<eT,T1>& expr, const uword gaus_id) const
{
arma_extra_debug_sigprint();
const quasi_unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
return internal_sum_log_p(X, gaus_id);
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::avg_log_p(const Base<eT,T1>& expr) const
{
arma_extra_debug_sigprint();
const quasi_unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
return internal_avg_log_p(X);
}
template<typename eT>
template<typename T1>
inline
eT
gmm_full<eT>::avg_log_p(const Base<eT,T1>& expr, const uword gaus_id) const
{
arma_extra_debug_sigprint();
const quasi_unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
return internal_avg_log_p(X, gaus_id);
}
template<typename eT>
template<typename T1>
inline
uword
gmm_full<eT>::assign(const T1& expr, const gmm_dist_mode& dist, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == true))>::result* junk) const
{
arma_extra_debug_sigprint();
arma_ignore(junk);
const quasi_unwrap<T1> tmp(expr);
const Mat<eT>& X = tmp.M;
return internal_scalar_assign(X, dist);
}
template<typename eT>
template<typename T1>
inline
urowvec
gmm_full<eT>::assign(const T1& expr, const gmm_dist_mode& dist, typename enable_if<((is_arma_type<T1>::value) && (resolves_to_colvector<T1>::value == false))>::result* junk) const
{
arma_extra_debug_sigprint();
arma_ignore(junk);
urowvec out;
const quasi_unwrap<T1> tmp(expr);
const Mat<eT>& X = tmp.M;
internal_vec_assign(out, X, dist);
return out;
}
template<typename eT>
template<typename T1>
inline
urowvec
gmm_full<eT>::raw_hist(const Base<eT,T1>& expr, const gmm_dist_mode& dist_mode) const
{
arma_extra_debug_sigprint();
const unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
arma_debug_check( (X.n_rows != means.n_rows), "gmm_full::raw_hist(): incompatible dimensions" );
arma_debug_check( ((dist_mode != eucl_dist) && (dist_mode != prob_dist)), "gmm_full::raw_hist(): unsupported distance mode" );
urowvec hist;
internal_raw_hist(hist, X, dist_mode);
return hist;
}
template<typename eT>
template<typename T1>
inline
Row<eT>
gmm_full<eT>::norm_hist(const Base<eT,T1>& expr, const gmm_dist_mode& dist_mode) const
{
arma_extra_debug_sigprint();
const unwrap<T1> tmp(expr.get_ref());
const Mat<eT>& X = tmp.M;
arma_debug_check( (X.n_rows != means.n_rows), "gmm_full::norm_hist(): incompatible dimensions" );
arma_debug_check( ((dist_mode != eucl_dist) && (dist_mode != prob_dist)), "gmm_full::norm_hist(): unsupported distance mode" );
urowvec hist;
internal_raw_hist(hist, X, dist_mode);
const uword hist_n_elem = hist.n_elem;
const uword* hist_mem = hist.memptr();
eT acc = eT(0);
for(uword i=0; i<hist_n_elem; ++i) { acc += eT(hist_mem[i]); }
if(acc == eT(0)) { acc = eT(1); }
Row<eT> out(hist_n_elem);
eT* out_mem = out.memptr();
for(uword i=0; i<hist_n_elem; ++i) { out_mem[i] = eT(hist_mem[i]) / acc; }
return out;
}
template<typename eT>
template<typename T1>
inline
bool
gmm_full<eT>::learn
(
const Base<eT,T1>& data,
const uword N_gaus,
const gmm_dist_mode& dist_mode,
const gmm_seed_mode& seed_mode,
const uword km_iter,
const uword em_iter,
const eT var_floor,
const bool print_mode
)
{
arma_extra_debug_sigprint();
const bool dist_mode_ok = (dist_mode == eucl_dist) || (dist_mode == maha_dist);
const bool seed_mode_ok = \
(seed_mode == keep_existing)
|| (seed_mode == static_subset)
|| (seed_mode == static_spread)
|| (seed_mode == random_subset)
|| (seed_mode == random_spread);
arma_debug_check( (dist_mode_ok == false), "gmm_full::learn(): dist_mode must be eucl_dist or maha_dist" );
arma_debug_check( (seed_mode_ok == false), "gmm_full::learn(): unknown seed_mode" );
arma_debug_check( (var_floor < eT(0) ), "gmm_full::learn(): variance floor is negative" );
const unwrap<T1> tmp_X(data.get_ref());
const Mat<eT>& X = tmp_X.M;
if(X.is_empty() ) { arma_debug_warn("gmm_full::learn(): given matrix is empty" ); return false; }
if(X.is_finite() == false) { arma_debug_warn("gmm_full::learn(): given matrix has non-finite values"); return false; }
if(N_gaus == 0) { reset(); return true; }
if(dist_mode == maha_dist)
{
mah_aux = var(X,1,1);
const uword mah_aux_n_elem = mah_aux.n_elem;
eT* mah_aux_mem = mah_aux.memptr();
for(uword i=0; i < mah_aux_n_elem; ++i)
{
const eT val = mah_aux_mem[i];
mah_aux_mem[i] = ((val != eT(0)) && arma_isfinite(val)) ? eT(1) / val : eT(1);
}
}
// copy current model, in case of failure by k-means and/or EM
const gmm_full<eT> orig = (*this);
// initial means
if(seed_mode == keep_existing)
{
if(means.is_empty() ) { arma_debug_warn("gmm_full::learn(): no existing means" ); return false; }
if(X.n_rows != means.n_rows) { arma_debug_warn("gmm_full::learn(): dimensionality mismatch"); return false; }
// TODO: also check for number of vectors?
}
else
{
if(X.n_cols < N_gaus) { arma_debug_warn("gmm_full::learn(): number of vectors is less than number of gaussians"); return false; }
reset(X.n_rows, N_gaus);
if(print_mode) { get_cout_stream() << "gmm_full::learn(): generating initial means\n"; get_cout_stream().flush(); }
if(dist_mode == eucl_dist) { generate_initial_means<1>(X, seed_mode); }
else if(dist_mode == maha_dist) { generate_initial_means<2>(X, seed_mode); }
}
// k-means
if(km_iter > 0)
{
const arma_ostream_state stream_state(get_cout_stream());
bool status = false;
if(dist_mode == eucl_dist) { status = km_iterate<1>(X, km_iter, print_mode); }
else if(dist_mode == maha_dist) { status = km_iterate<2>(X, km_iter, print_mode); }
stream_state.restore(get_cout_stream());
if(status == false) { arma_debug_warn("gmm_full::learn(): k-means algorithm failed; not enough data, or too many gaussians requested"); init(orig); return false; }
}
// initial fcovs
const eT var_floor_actual = (eT(var_floor) > eT(0)) ? eT(var_floor) : std::numeric_limits<eT>::min();
if(seed_mode != keep_existing)
{
if(print_mode) { get_cout_stream() << "gmm_full::learn(): generating initial covariances\n"; get_cout_stream().flush(); }
if(dist_mode == eucl_dist) { generate_initial_params<1>(X, var_floor_actual); }
else if(dist_mode == maha_dist) { generate_initial_params<2>(X, var_floor_actual); }
}
// EM algorithm
if(em_iter > 0)
{
const arma_ostream_state stream_state(get_cout_stream());
const bool status = em_iterate(X, em_iter, var_floor_actual, print_mode);
stream_state.restore(get_cout_stream());
if(status == false) { arma_debug_warn("gmm_full::learn(): EM algorithm failed"); init(orig); return false; }
}
mah_aux.reset();
init_constants();
return true;
}
//
//
//
template<typename eT>
inline
void
gmm_full<eT>::init(const gmm_full<eT>& x)
{
arma_extra_debug_sigprint();
gmm_full<eT>& t = *this;
if(&t != &x)
{
access::rw(t.means) = x.means;
access::rw(t.fcovs) = x.fcovs;
access::rw(t.hefts) = x.hefts;
init_constants();
}
}
template<typename eT>
inline
void
gmm_full<eT>::init(const gmm_diag<eT>& x)
{
arma_extra_debug_sigprint();
access::rw(hefts) = x.hefts;
access::rw(means) = x.means;
const uword N_dims = x.means.n_rows;
const uword N_gaus = x.means.n_cols;
access::rw(fcovs).zeros(N_dims,N_dims,N_gaus);
for(uword g=0; g < N_gaus; ++g)
{
Mat<eT>& fcov = access::rw(fcovs).slice(g);
const eT* dcov_mem = x.dcovs.colptr(g);
for(uword d=0; d < N_dims; ++d)
{
fcov.at(d,d) = dcov_mem[d];
}
}
init_constants();
}
template<typename eT>
inline
void
gmm_full<eT>::init(const uword in_n_dims, const uword in_n_gaus)
{
arma_extra_debug_sigprint();
access::rw(means).zeros(in_n_dims, in_n_gaus);
access::rw(fcovs).zeros(in_n_dims, in_n_dims, in_n_gaus);
for(uword g=0; g < in_n_gaus; ++g)
{
access::rw(fcovs).slice(g).diag().ones();
}
access::rw(hefts).set_size(in_n_gaus);
access::rw(hefts).fill(eT(1) / eT(in_n_gaus));
init_constants();
}
template<typename eT>
inline
void
gmm_full<eT>::init_constants(const bool calc_chol)
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const eT tmp = (eT(N_dims)/eT(2)) * std::log(eT(2) * Datum<eT>::pi);
//
inv_fcovs.copy_size(fcovs);
log_det_etc.set_size(N_gaus);
Mat<eT> tmp_inv;
for(uword g=0; g < N_gaus; ++g)
{
const Mat<eT>& fcov = fcovs.slice(g);
Mat<eT>& inv_fcov = inv_fcovs.slice(g);
//const bool inv_ok = auxlib::inv(tmp_inv, fcov);
const bool inv_ok = auxlib::inv_sympd(tmp_inv, fcov);
eT log_det_val = eT(0);
eT log_det_sign = eT(0);
log_det(log_det_val, log_det_sign, fcov);
const bool log_det_ok = ( (arma_isfinite(log_det_val)) && (log_det_sign > eT(0)) );
if(inv_ok && log_det_ok)
{
inv_fcov = tmp_inv;
}
else
{
// last resort: treat the covariance matrix as diagonal
inv_fcov.zeros();
log_det_val = eT(0);
for(uword d=0; d < N_dims; ++d)
{
const eT sanitised_val = (std::max)( eT(fcov.at(d,d)), eT(std::numeric_limits<eT>::min()) );
inv_fcov.at(d,d) = eT(1) / sanitised_val;
log_det_val += std::log(sanitised_val);
}
}
log_det_etc[g] = eT(-1) * ( tmp + eT(0.5) * log_det_val );
}
//
eT* hefts_mem = access::rw(hefts).memptr();
for(uword g=0; g < N_gaus; ++g)
{
hefts_mem[g] = (std::max)( hefts_mem[g], std::numeric_limits<eT>::min() );
}
log_hefts = log(hefts);
if(calc_chol)
{
chol_fcovs.copy_size(fcovs);
Mat<eT> tmp_chol;
for(uword g=0; g < N_gaus; ++g)
{
const Mat<eT>& fcov = fcovs.slice(g);
Mat<eT>& chol_fcov = chol_fcovs.slice(g);
const uword chol_layout = 1; // indicates "lower"
const bool chol_ok = op_chol::apply_direct(tmp_chol, fcov, chol_layout);
if(chol_ok)
{
chol_fcov = tmp_chol;
}
else
{
// last resort: treat the covariance matrix as diagonal
chol_fcov.zeros();
for(uword d=0; d < N_dims; ++d)
{
const eT sanitised_val = (std::max)( eT(fcov.at(d,d)), eT(std::numeric_limits<eT>::min()) );
chol_fcov.at(d,d) = std::sqrt(sanitised_val);
}
}
}
}
}
template<typename eT>
inline
umat
gmm_full<eT>::internal_gen_boundaries(const uword N) const
{
arma_extra_debug_sigprint();
#if defined(ARMA_USE_OPENMP)
const uword n_threads_avail = uword(omp_get_max_threads());
const uword n_threads = (n_threads_avail > 0) ? ( (n_threads_avail <= N) ? n_threads_avail : 1 ) : 1;
#else
static const uword n_threads = 1;
#endif
// get_cout_stream() << "gmm_full::internal_gen_boundaries(): n_threads: " << n_threads << '\n';
umat boundaries(2, n_threads);
if(N > 0)
{
const uword chunk_size = N / n_threads;
uword count = 0;
for(uword t=0; t<n_threads; t++)
{
boundaries.at(0,t) = count;
count += chunk_size;
boundaries.at(1,t) = count-1;
}
boundaries.at(1,n_threads-1) = N - 1;
}
else
{
boundaries.zeros();
}
// get_cout_stream() << "gmm_full::internal_gen_boundaries(): boundaries: " << '\n' << boundaries << '\n';
return boundaries;
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_scalar_log_p(const eT* x) const
{
arma_extra_debug_sigprint();
const eT* log_hefts_mem = log_hefts.mem;
const uword N_gaus = means.n_cols;
if(N_gaus > 0)
{
eT log_sum = internal_scalar_log_p(x, 0) + log_hefts_mem[0];
for(uword g=1; g < N_gaus; ++g)
{
const eT log_val = internal_scalar_log_p(x, g) + log_hefts_mem[g];
log_sum = log_add_exp(log_sum, log_val);
}
return log_sum;
}
else
{
return -Datum<eT>::inf;
}
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_scalar_log_p(const eT* x, const uword g) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const eT* mean_mem = means.colptr(g);
eT outer_acc = eT(0);
const eT* inv_fcov_coldata = inv_fcovs.slice(g).memptr();
for(uword i=0; i < N_dims; ++i)
{
eT inner_acc = eT(0);
for(uword j=0; j < N_dims; ++j)
{
inner_acc += (x[j] - mean_mem[j]) * inv_fcov_coldata[j];
}
inv_fcov_coldata += N_dims;
outer_acc += inner_acc * (x[i] - mean_mem[i]);
}
return eT(-0.5)*outer_acc + log_det_etc.mem[g];
}
template<typename eT>
inline
Row<eT>
gmm_full<eT>::internal_vec_log_p(const Mat<eT>& X) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_samples = X.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::log_p(): incompatible dimensions" );
Row<eT> out(N_samples);
if(N_samples > 0)
{
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N_samples);
const uword n_threads = boundaries.n_cols;
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
eT* out_mem = out.memptr();
for(uword i=start_index; i <= end_index; ++i)
{
out_mem[i] = internal_scalar_log_p( X.colptr(i) );
}
}
}
#else
{
eT* out_mem = out.memptr();
for(uword i=0; i < N_samples; ++i)
{
out_mem[i] = internal_scalar_log_p( X.colptr(i) );
}
}
#endif
}
return out;
}
template<typename eT>
inline
Row<eT>
gmm_full<eT>::internal_vec_log_p(const Mat<eT>& X, const uword gaus_id) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_samples = X.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::log_p(): incompatible dimensions" );
arma_debug_check( (gaus_id >= means.n_cols), "gmm_full::log_p(): specified gaussian is out of range" );
Row<eT> out(N_samples);
if(N_samples > 0)
{
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N_samples);
const uword n_threads = boundaries.n_cols;
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
eT* out_mem = out.memptr();
for(uword i=start_index; i <= end_index; ++i)
{
out_mem[i] = internal_scalar_log_p( X.colptr(i), gaus_id );
}
}
}
#else
{
eT* out_mem = out.memptr();
for(uword i=0; i < N_samples; ++i)
{
out_mem[i] = internal_scalar_log_p( X.colptr(i), gaus_id );
}
}
#endif
}
return out;
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_sum_log_p(const Mat<eT>& X) const
{
arma_extra_debug_sigprint();
arma_debug_check( (X.n_rows != means.n_rows), "gmm_full::sum_log_p(): incompatible dimensions" );
const uword N = X.n_cols;
if(N == 0) { return (-Datum<eT>::inf); }
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N);
const uword n_threads = boundaries.n_cols;
Col<eT> t_accs(n_threads, fill::zeros);
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
eT t_acc = eT(0);
for(uword i=start_index; i <= end_index; ++i)
{
t_acc += internal_scalar_log_p( X.colptr(i) );
}
t_accs[t] = t_acc;
}
return eT(accu(t_accs));
}
#else
{
eT acc = eT(0);
for(uword i=0; i<N; ++i)
{
acc += internal_scalar_log_p( X.colptr(i) );
}
return acc;
}
#endif
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_sum_log_p(const Mat<eT>& X, const uword gaus_id) const
{
arma_extra_debug_sigprint();
arma_debug_check( (X.n_rows != means.n_rows), "gmm_full::sum_log_p(): incompatible dimensions" );
arma_debug_check( (gaus_id >= means.n_cols), "gmm_full::sum_log_p(): specified gaussian is out of range" );
const uword N = X.n_cols;
if(N == 0) { return (-Datum<eT>::inf); }
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N);
const uword n_threads = boundaries.n_cols;
Col<eT> t_accs(n_threads, fill::zeros);
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
eT t_acc = eT(0);
for(uword i=start_index; i <= end_index; ++i)
{
t_acc += internal_scalar_log_p( X.colptr(i), gaus_id );
}
t_accs[t] = t_acc;
}
return eT(accu(t_accs));
}
#else
{
eT acc = eT(0);
for(uword i=0; i<N; ++i)
{
acc += internal_scalar_log_p( X.colptr(i), gaus_id );
}
return acc;
}
#endif
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_avg_log_p(const Mat<eT>& X) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_samples = X.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::avg_log_p(): incompatible dimensions" );
if(N_samples == 0) { return (-Datum<eT>::inf); }
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N_samples);
const uword n_threads = boundaries.n_cols;
field< running_mean_scalar<eT> > t_running_means(n_threads);
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
running_mean_scalar<eT>& current_running_mean = t_running_means[t];
for(uword i=start_index; i <= end_index; ++i)
{
current_running_mean( internal_scalar_log_p( X.colptr(i) ) );
}
}
eT avg = eT(0);
for(uword t=0; t < n_threads; ++t)
{
running_mean_scalar<eT>& current_running_mean = t_running_means[t];
const eT w = eT(current_running_mean.count()) / eT(N_samples);
avg += w * current_running_mean.mean();
}
return avg;
}
#else
{
running_mean_scalar<eT> running_mean;
for(uword i=0; i < N_samples; ++i)
{
running_mean( internal_scalar_log_p( X.colptr(i) ) );
}
return running_mean.mean();
}
#endif
}
template<typename eT>
inline
eT
gmm_full<eT>::internal_avg_log_p(const Mat<eT>& X, const uword gaus_id) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_samples = X.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::avg_log_p(): incompatible dimensions" );
arma_debug_check( (gaus_id >= means.n_cols), "gmm_full::avg_log_p(): specified gaussian is out of range" );
if(N_samples == 0) { return (-Datum<eT>::inf); }
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(N_samples);
const uword n_threads = boundaries.n_cols;
field< running_mean_scalar<eT> > t_running_means(n_threads);
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
running_mean_scalar<eT>& current_running_mean = t_running_means[t];
for(uword i=start_index; i <= end_index; ++i)
{
current_running_mean( internal_scalar_log_p( X.colptr(i), gaus_id) );
}
}
eT avg = eT(0);
for(uword t=0; t < n_threads; ++t)
{
running_mean_scalar<eT>& current_running_mean = t_running_means[t];
const eT w = eT(current_running_mean.count()) / eT(N_samples);
avg += w * current_running_mean.mean();
}
return avg;
}
#else
{
running_mean_scalar<eT> running_mean;
for(uword i=0; i<N_samples; ++i)
{
running_mean( internal_scalar_log_p( X.colptr(i), gaus_id ) );
}
return running_mean.mean();
}
#endif
}
template<typename eT>
inline
uword
gmm_full<eT>::internal_scalar_assign(const Mat<eT>& X, const gmm_dist_mode& dist_mode) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::assign(): incompatible dimensions" );
arma_debug_check( (N_gaus == 0), "gmm_full::assign(): model has no means" );
const eT* X_mem = X.colptr(0);
if(dist_mode == eucl_dist)
{
eT best_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_dist = distance<eT,1>::eval(N_dims, X_mem, means.colptr(g), X_mem);
if(tmp_dist <= best_dist)
{
best_dist = tmp_dist;
best_g = g;
}
}
return best_g;
}
else
if(dist_mode == prob_dist)
{
const eT* log_hefts_mem = log_hefts.memptr();
eT best_p = -Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_p = internal_scalar_log_p(X_mem, g) + log_hefts_mem[g];
if(tmp_p >= best_p)
{
best_p = tmp_p;
best_g = g;
}
}
return best_g;
}
else
{
arma_debug_check(true, "gmm_full::assign(): unsupported distance mode");
}
return uword(0);
}
template<typename eT>
inline
void
gmm_full<eT>::internal_vec_assign(urowvec& out, const Mat<eT>& X, const gmm_dist_mode& dist_mode) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
arma_debug_check( (X.n_rows != N_dims), "gmm_full::assign(): incompatible dimensions" );
const uword X_n_cols = (N_gaus > 0) ? X.n_cols : 0;
out.set_size(1,X_n_cols);
uword* out_mem = out.memptr();
if(dist_mode == eucl_dist)
{
#if defined(ARMA_USE_OPENMP)
{
#pragma omp parallel for schedule(static)
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT tmp_dist = distance<eT,1>::eval(N_dims, X_colptr, means.colptr(g), X_colptr);
if(tmp_dist <= best_dist) { best_dist = tmp_dist; best_g = g; }
}
out_mem[i] = best_g;
}
}
#else
{
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT tmp_dist = distance<eT,1>::eval(N_dims, X_colptr, means.colptr(g), X_colptr);
if(tmp_dist <= best_dist) { best_dist = tmp_dist; best_g = g; }
}
out_mem[i] = best_g;
}
}
#endif
}
else
if(dist_mode == prob_dist)
{
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(X_n_cols);
const uword n_threads = boundaries.n_cols;
const eT* log_hefts_mem = log_hefts.memptr();
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
for(uword i=start_index; i <= end_index; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_p = -Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT tmp_p = internal_scalar_log_p(X_colptr, g) + log_hefts_mem[g];
if(tmp_p >= best_p) { best_p = tmp_p; best_g = g; }
}
out_mem[i] = best_g;
}
}
}
#else
{
const eT* log_hefts_mem = log_hefts.memptr();
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_p = -Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT tmp_p = internal_scalar_log_p(X_colptr, g) + log_hefts_mem[g];
if(tmp_p >= best_p) { best_p = tmp_p; best_g = g; }
}
out_mem[i] = best_g;
}
}
#endif
}
else
{
arma_debug_check(true, "gmm_full::assign(): unsupported distance mode");
}
}
template<typename eT>
inline
void
gmm_full<eT>::internal_raw_hist(urowvec& hist, const Mat<eT>& X, const gmm_dist_mode& dist_mode) const
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const uword X_n_cols = X.n_cols;
hist.zeros(N_gaus);
if(N_gaus == 0) { return; }
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(X_n_cols);
const uword n_threads = boundaries.n_cols;
field<urowvec> thread_hist(n_threads);
for(uword t=0; t < n_threads; ++t) { thread_hist(t).zeros(N_gaus); }
if(dist_mode == eucl_dist)
{
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
uword* thread_hist_mem = thread_hist(t).memptr();
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
for(uword i=start_index; i <= end_index; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_dist = distance<eT,1>::eval(N_dims, X_colptr, means.colptr(g), X_colptr);
if(tmp_dist <= best_dist) { best_dist = tmp_dist; best_g = g; }
}
thread_hist_mem[best_g]++;
}
}
}
else
if(dist_mode == prob_dist)
{
const eT* log_hefts_mem = log_hefts.memptr();
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
uword* thread_hist_mem = thread_hist(t).memptr();
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
for(uword i=start_index; i <= end_index; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_p = -Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_p = internal_scalar_log_p(X_colptr, g) + log_hefts_mem[g];
if(tmp_p >= best_p) { best_p = tmp_p; best_g = g; }
}
thread_hist_mem[best_g]++;
}
}
}
// reduction
for(uword t=0; t < n_threads; ++t)
{
hist += thread_hist(t);
}
}
#else
{
uword* hist_mem = hist.memptr();
if(dist_mode == eucl_dist)
{
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_dist = distance<eT,1>::eval(N_dims, X_colptr, means.colptr(g), X_colptr);
if(tmp_dist <= best_dist) { best_dist = tmp_dist; best_g = g; }
}
hist_mem[best_g]++;
}
}
else
if(dist_mode == prob_dist)
{
const eT* log_hefts_mem = log_hefts.memptr();
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT best_p = -Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g < N_gaus; ++g)
{
const eT tmp_p = internal_scalar_log_p(X_colptr, g) + log_hefts_mem[g];
if(tmp_p >= best_p) { best_p = tmp_p; best_g = g; }
}
hist_mem[best_g]++;
}
}
}
#endif
}
template<typename eT>
template<uword dist_id>
inline
void
gmm_full<eT>::generate_initial_means(const Mat<eT>& X, const gmm_seed_mode& seed_mode)
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
if( (seed_mode == static_subset) || (seed_mode == random_subset) )
{
uvec initial_indices;
if(seed_mode == static_subset) { initial_indices = linspace<uvec>(0, X.n_cols-1, N_gaus); }
else if(seed_mode == random_subset) { initial_indices = randperm<uvec>(X.n_cols, N_gaus); }
// initial_indices.print("initial_indices:");
access::rw(means) = X.cols(initial_indices);
}
else
if( (seed_mode == static_spread) || (seed_mode == random_spread) )
{
// going through all of the samples can be extremely time consuming;
// instead, if there are enough samples, randomly choose samples with probability 0.1
const bool use_sampling = ((X.n_cols/uword(100)) > N_gaus);
const uword step = (use_sampling) ? uword(10) : uword(1);
uword start_index = 0;
if(seed_mode == static_spread) { start_index = X.n_cols / 2; }
else if(seed_mode == random_spread) { start_index = as_scalar(randi<uvec>(1, distr_param(0,X.n_cols-1))); }
access::rw(means).col(0) = X.unsafe_col(start_index);
const eT* mah_aux_mem = mah_aux.memptr();
running_stat<double> rs;
for(uword g=1; g < N_gaus; ++g)
{
eT max_dist = eT(0);
uword best_i = uword(0);
uword start_i = uword(0);
if(use_sampling)
{
uword start_i_proposed = uword(0);
if(seed_mode == static_spread) { start_i_proposed = g % uword(10); }
if(seed_mode == random_spread) { start_i_proposed = as_scalar(randi<uvec>(1, distr_param(0,9))); }
if(start_i_proposed < X.n_cols) { start_i = start_i_proposed; }
}
for(uword i=start_i; i < X.n_cols; i += step)
{
rs.reset();
const eT* X_colptr = X.colptr(i);
bool ignore_i = false;
// find the average distance between sample i and the means so far
for(uword h = 0; h < g; ++h)
{
const eT dist = distance<eT,dist_id>::eval(N_dims, X_colptr, means.colptr(h), mah_aux_mem);
// ignore sample already selected as a mean
if(dist == eT(0)) { ignore_i = true; break; }
else { rs(dist); }
}
if( (rs.mean() >= max_dist) && (ignore_i == false))
{
max_dist = eT(rs.mean()); best_i = i;
}
}
// set the mean to the sample that is the furthest away from the means so far
access::rw(means).col(g) = X.unsafe_col(best_i);
}
}
// get_cout_stream() << "generate_initial_means():" << '\n';
// means.print();
}
template<typename eT>
template<uword dist_id>
inline
void
gmm_full<eT>::generate_initial_params(const Mat<eT>& X, const eT var_floor)
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const eT* mah_aux_mem = mah_aux.memptr();
const uword X_n_cols = X.n_cols;
if(X_n_cols == 0) { return; }
// as the covariances are calculated via accumulators,
// the means also need to be calculated via accumulators to ensure numerical consistency
Mat<eT> acc_means(N_dims, N_gaus, fill::zeros);
Mat<eT> acc_dcovs(N_dims, N_gaus, fill::zeros);
Row<uword> acc_hefts(N_gaus, fill::zeros);
uword* acc_hefts_mem = acc_hefts.memptr();
#if defined(ARMA_USE_OPENMP)
{
const umat boundaries = internal_gen_boundaries(X_n_cols);
const uword n_threads = boundaries.n_cols;
field< Mat<eT> > t_acc_means(n_threads);
field< Mat<eT> > t_acc_dcovs(n_threads);
field< Row<uword> > t_acc_hefts(n_threads);
for(uword t=0; t < n_threads; ++t)
{
t_acc_means(t).zeros(N_dims, N_gaus);
t_acc_dcovs(t).zeros(N_dims, N_gaus);
t_acc_hefts(t).zeros(N_gaus);
}
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
uword* t_acc_hefts_mem = t_acc_hefts(t).memptr();
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
for(uword i=start_index; i <= end_index; ++i)
{
const eT* X_colptr = X.colptr(i);
eT min_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT dist = distance<eT,dist_id>::eval(N_dims, X_colptr, means.colptr(g), mah_aux_mem);
if(dist < min_dist) { min_dist = dist; best_g = g; }
}
eT* t_acc_mean = t_acc_means(t).colptr(best_g);
eT* t_acc_dcov = t_acc_dcovs(t).colptr(best_g);
for(uword d=0; d<N_dims; ++d)
{
const eT x_d = X_colptr[d];
t_acc_mean[d] += x_d;
t_acc_dcov[d] += x_d*x_d;
}
t_acc_hefts_mem[best_g]++;
}
}
// reduction
acc_means = t_acc_means(0);
acc_dcovs = t_acc_dcovs(0);
acc_hefts = t_acc_hefts(0);
for(uword t=1; t < n_threads; ++t)
{
acc_means += t_acc_means(t);
acc_dcovs += t_acc_dcovs(t);
acc_hefts += t_acc_hefts(t);
}
}
#else
{
for(uword i=0; i<X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT min_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT dist = distance<eT,dist_id>::eval(N_dims, X_colptr, means.colptr(g), mah_aux_mem);
if(dist < min_dist) { min_dist = dist; best_g = g; }
}
eT* acc_mean = acc_means.colptr(best_g);
eT* acc_dcov = acc_dcovs.colptr(best_g);
for(uword d=0; d<N_dims; ++d)
{
const eT x_d = X_colptr[d];
acc_mean[d] += x_d;
acc_dcov[d] += x_d*x_d;
}
acc_hefts_mem[best_g]++;
}
}
#endif
eT* hefts_mem = access::rw(hefts).memptr();
for(uword g=0; g<N_gaus; ++g)
{
const eT* acc_mean = acc_means.colptr(g);
const eT* acc_dcov = acc_dcovs.colptr(g);
const uword acc_heft = acc_hefts_mem[g];
eT* mean = access::rw(means).colptr(g);
Mat<eT>& fcov = access::rw(fcovs).slice(g);
fcov.zeros();
for(uword d=0; d<N_dims; ++d)
{
const eT tmp = acc_mean[d] / eT(acc_heft);
mean[d] = (acc_heft >= 1) ? tmp : eT(0);
fcov.at(d,d) = (acc_heft >= 2) ? eT((acc_dcov[d] / eT(acc_heft)) - (tmp*tmp)) : eT(var_floor);
}
hefts_mem[g] = eT(acc_heft) / eT(X_n_cols);
}
em_fix_params(var_floor);
}
//! multi-threaded implementation of k-means, inspired by MapReduce
template<typename eT>
template<uword dist_id>
inline
bool
gmm_full<eT>::km_iterate(const Mat<eT>& X, const uword max_iter, const bool verbose)
{
arma_extra_debug_sigprint();
if(verbose)
{
get_cout_stream().unsetf(ios::showbase);
get_cout_stream().unsetf(ios::uppercase);
get_cout_stream().unsetf(ios::showpos);
get_cout_stream().unsetf(ios::scientific);
get_cout_stream().setf(ios::right);
get_cout_stream().setf(ios::fixed);
}
const uword X_n_cols = X.n_cols;
if(X_n_cols == 0) { return true; }
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const eT* mah_aux_mem = mah_aux.memptr();
Mat<eT> acc_means(N_dims, N_gaus, fill::zeros);
Row<uword> acc_hefts(N_gaus, fill::zeros);
Row<uword> last_indx(N_gaus, fill::zeros);
Mat<eT> new_means = means;
Mat<eT> old_means = means;
running_mean_scalar<eT> rs_delta;
#if defined(ARMA_USE_OPENMP)
const umat boundaries = internal_gen_boundaries(X_n_cols);
const uword n_threads = boundaries.n_cols;
field< Mat<eT> > t_acc_means(n_threads);
field< Row<uword> > t_acc_hefts(n_threads);
field< Row<uword> > t_last_indx(n_threads);
#else
const uword n_threads = 1;
#endif
if(verbose) { get_cout_stream() << "gmm_full::learn(): k-means: n_threads: " << n_threads << '\n'; get_cout_stream().flush(); }
for(uword iter=1; iter <= max_iter; ++iter)
{
#if defined(ARMA_USE_OPENMP)
{
for(uword t=0; t < n_threads; ++t)
{
t_acc_means(t).zeros(N_dims, N_gaus);
t_acc_hefts(t).zeros(N_gaus);
t_last_indx(t).zeros(N_gaus);
}
#pragma omp parallel for schedule(static)
for(uword t=0; t < n_threads; ++t)
{
Mat<eT>& t_acc_means_t = t_acc_means(t);
uword* t_acc_hefts_mem = t_acc_hefts(t).memptr();
uword* t_last_indx_mem = t_last_indx(t).memptr();
const uword start_index = boundaries.at(0,t);
const uword end_index = boundaries.at(1,t);
for(uword i=start_index; i <= end_index; ++i)
{
const eT* X_colptr = X.colptr(i);
eT min_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT dist = distance<eT,dist_id>::eval(N_dims, X_colptr, old_means.colptr(g), mah_aux_mem);
if(dist < min_dist) { min_dist = dist; best_g = g; }
}
eT* t_acc_mean = t_acc_means_t.colptr(best_g);
for(uword d=0; d<N_dims; ++d) { t_acc_mean[d] += X_colptr[d]; }
t_acc_hefts_mem[best_g]++;
t_last_indx_mem[best_g] = i;
}
}
// reduction
acc_means = t_acc_means(0);
acc_hefts = t_acc_hefts(0);
for(uword t=1; t < n_threads; ++t)
{
acc_means += t_acc_means(t);
acc_hefts += t_acc_hefts(t);
}
for(uword g=0; g < N_gaus; ++g)
for(uword t=0; t < n_threads; ++t)
{
if( t_acc_hefts(t)(g) >= 1 ) { last_indx(g) = t_last_indx(t)(g); }
}
}
#else
{
acc_hefts.zeros();
acc_means.zeros();
last_indx.zeros();
uword* acc_hefts_mem = acc_hefts.memptr();
uword* last_indx_mem = last_indx.memptr();
for(uword i=0; i < X_n_cols; ++i)
{
const eT* X_colptr = X.colptr(i);
eT min_dist = Datum<eT>::inf;
uword best_g = 0;
for(uword g=0; g<N_gaus; ++g)
{
const eT dist = distance<eT,dist_id>::eval(N_dims, X_colptr, old_means.colptr(g), mah_aux_mem);
if(dist < min_dist) { min_dist = dist; best_g = g; }
}
eT* acc_mean = acc_means.colptr(best_g);
for(uword d=0; d<N_dims; ++d) { acc_mean[d] += X_colptr[d]; }
acc_hefts_mem[best_g]++;
last_indx_mem[best_g] = i;
}
}
#endif
// generate new means
uword* acc_hefts_mem = acc_hefts.memptr();
for(uword g=0; g < N_gaus; ++g)
{
const eT* acc_mean = acc_means.colptr(g);
const uword acc_heft = acc_hefts_mem[g];
eT* new_mean = access::rw(new_means).colptr(g);
for(uword d=0; d<N_dims; ++d)
{
new_mean[d] = (acc_heft >= 1) ? (acc_mean[d] / eT(acc_heft)) : eT(0);
}
}
// heuristics to resurrect dead means
const uvec dead_gs = find(acc_hefts == uword(0));
if(dead_gs.n_elem > 0)
{
if(verbose) { get_cout_stream() << "gmm_full::learn(): k-means: recovering from dead means\n"; get_cout_stream().flush(); }
uword* last_indx_mem = last_indx.memptr();
const uvec live_gs = sort( find(acc_hefts >= uword(2)), "descend" );
if(live_gs.n_elem == 0) { return false; }
uword live_gs_count = 0;
for(uword dead_gs_count = 0; dead_gs_count < dead_gs.n_elem; ++dead_gs_count)
{
const uword dead_g_id = dead_gs(dead_gs_count);
uword proposed_i = 0;
if(live_gs_count < live_gs.n_elem)
{
const uword live_g_id = live_gs(live_gs_count); ++live_gs_count;
if(live_g_id == dead_g_id) { return false; }
// recover by using a sample from a known good mean
proposed_i = last_indx_mem[live_g_id];
}
else
{
// recover by using a randomly seleced sample (last resort)
proposed_i = as_scalar(randi<uvec>(1, distr_param(0,X_n_cols-1)));
}
if(proposed_i >= X_n_cols) { return false; }
new_means.col(dead_g_id) = X.col(proposed_i);
}
}
rs_delta.reset();
for(uword g=0; g < N_gaus; ++g)
{
rs_delta( distance<eT,dist_id>::eval(N_dims, old_means.colptr(g), new_means.colptr(g), mah_aux_mem) );
}
if(verbose)
{
get_cout_stream() << "gmm_full::learn(): k-means: iteration: ";
get_cout_stream().unsetf(ios::scientific);
get_cout_stream().setf(ios::fixed);
get_cout_stream().width(std::streamsize(4));
get_cout_stream() << iter;
get_cout_stream() << " delta: ";
get_cout_stream().unsetf(ios::fixed);
//get_cout_stream().setf(ios::scientific);
get_cout_stream() << rs_delta.mean() << '\n';
get_cout_stream().flush();
}
arma::swap(old_means, new_means);
if(rs_delta.mean() <= Datum<eT>::eps) { break; }
}
access::rw(means) = old_means;
if(means.is_finite() == false) { return false; }
return true;
}
//! multi-threaded implementation of Expectation-Maximisation, inspired by MapReduce
template<typename eT>
inline
bool
gmm_full<eT>::em_iterate(const Mat<eT>& X, const uword max_iter, const eT var_floor, const bool verbose)
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
if(verbose)
{
get_cout_stream().unsetf(ios::showbase);
get_cout_stream().unsetf(ios::uppercase);
get_cout_stream().unsetf(ios::showpos);
get_cout_stream().unsetf(ios::scientific);
get_cout_stream().setf(ios::right);
get_cout_stream().setf(ios::fixed);
}
const umat boundaries = internal_gen_boundaries(X.n_cols);
const uword n_threads = boundaries.n_cols;
field< Mat<eT> > t_acc_means(n_threads);
field< Cube<eT> > t_acc_fcovs(n_threads);
field< Col<eT> > t_acc_norm_lhoods(n_threads);
field< Col<eT> > t_gaus_log_lhoods(n_threads);
Col<eT> t_progress_log_lhood(n_threads);
for(uword t=0; t<n_threads; t++)
{
t_acc_means[t].set_size(N_dims, N_gaus);
t_acc_fcovs[t].set_size(N_dims, N_dims, N_gaus);
t_acc_norm_lhoods[t].set_size(N_gaus);
t_gaus_log_lhoods[t].set_size(N_gaus);
}
if(verbose)
{
get_cout_stream() << "gmm_full::learn(): EM: n_threads: " << n_threads << '\n';
}
eT old_avg_log_p = -Datum<eT>::inf;
const bool calc_chol = false;
for(uword iter=1; iter <= max_iter; ++iter)
{
init_constants(calc_chol);
em_update_params(X, boundaries, t_acc_means, t_acc_fcovs, t_acc_norm_lhoods, t_gaus_log_lhoods, t_progress_log_lhood, var_floor);
em_fix_params(var_floor);
const eT new_avg_log_p = accu(t_progress_log_lhood) / eT(t_progress_log_lhood.n_elem);
if(verbose)
{
get_cout_stream() << "gmm_full::learn(): EM: iteration: ";
get_cout_stream().unsetf(ios::scientific);
get_cout_stream().setf(ios::fixed);
get_cout_stream().width(std::streamsize(4));
get_cout_stream() << iter;
get_cout_stream() << " avg_log_p: ";
get_cout_stream().unsetf(ios::fixed);
//get_cout_stream().setf(ios::scientific);
get_cout_stream() << new_avg_log_p << '\n';
get_cout_stream().flush();
}
if(arma_isfinite(new_avg_log_p) == false) { return false; }
if(std::abs(old_avg_log_p - new_avg_log_p) <= Datum<eT>::eps) { break; }
old_avg_log_p = new_avg_log_p;
}
for(uword g=0; g < N_gaus; ++g)
{
const Mat<eT>& fcov = fcovs.slice(g);
if(any(vectorise(fcov.diag()) <= eT(0))) { return false; }
}
if(means.is_finite() == false) { return false; }
if(fcovs.is_finite() == false) { return false; }
if(hefts.is_finite() == false) { return false; }
return true;
}
template<typename eT>
inline
void
gmm_full<eT>::em_update_params
(
const Mat<eT>& X,
const umat& boundaries,
field< Mat<eT> >& t_acc_means,
field< Cube<eT> >& t_acc_fcovs,
field< Col<eT> >& t_acc_norm_lhoods,
field< Col<eT> >& t_gaus_log_lhoods,
Col<eT>& t_progress_log_lhood,
const eT var_floor
)
{
arma_extra_debug_sigprint();
const uword n_threads = boundaries.n_cols;
// em_generate_acc() is the "map" operation, which produces partial accumulators for means, diagonal covariances and hefts
#if defined(ARMA_USE_OPENMP)
{
#pragma omp parallel for schedule(static)
for(uword t=0; t<n_threads; t++)
{
Mat<eT>& acc_means = t_acc_means[t];
Cube<eT>& acc_fcovs = t_acc_fcovs[t];
Col<eT>& acc_norm_lhoods = t_acc_norm_lhoods[t];
Col<eT>& gaus_log_lhoods = t_gaus_log_lhoods[t];
eT& progress_log_lhood = t_progress_log_lhood[t];
em_generate_acc(X, boundaries.at(0,t), boundaries.at(1,t), acc_means, acc_fcovs, acc_norm_lhoods, gaus_log_lhoods, progress_log_lhood);
}
}
#else
{
em_generate_acc(X, boundaries.at(0,0), boundaries.at(1,0), t_acc_means[0], t_acc_fcovs[0], t_acc_norm_lhoods[0], t_gaus_log_lhoods[0], t_progress_log_lhood[0]);
}
#endif
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
Mat<eT>& final_acc_means = t_acc_means[0];
Cube<eT>& final_acc_fcovs = t_acc_fcovs[0];
Col<eT>& final_acc_norm_lhoods = t_acc_norm_lhoods[0];
// the "reduce" operation, which combines the partial accumulators produced by the separate threads
for(uword t=1; t<n_threads; t++)
{
final_acc_means += t_acc_means[t];
final_acc_fcovs += t_acc_fcovs[t];
final_acc_norm_lhoods += t_acc_norm_lhoods[t];
}
eT* hefts_mem = access::rw(hefts).memptr();
Mat<eT> mean_outer(N_dims, N_dims);
//// update each component without sanity checking
//for(uword g=0; g < N_gaus; ++g)
// {
// const eT acc_norm_lhood = (std::max)( final_acc_norm_lhoods[g], std::numeric_limits<eT>::min() );
//
// hefts_mem[g] = acc_norm_lhood / eT(X.n_cols);
//
// eT* mean_mem = access::rw(means).colptr(g);
// eT* acc_mean_mem = final_acc_means.colptr(g);
//
// for(uword d=0; d < N_dims; ++d)
// {
// mean_mem[d] = acc_mean_mem[d] / acc_norm_lhood;
// }
//
// const Col<eT> mean(mean_mem, N_dims, false, true);
//
// mean_outer = mean * mean.t();
//
// Mat<eT>& fcov = access::rw(fcovs).slice(g);
// Mat<eT>& acc_fcov = final_acc_fcovs.slice(g);
//
// fcov = acc_fcov / acc_norm_lhood - mean_outer;
// }
// conditionally update each component; if only a subset of the hefts was updated, em_fix_params() will sanitise them
for(uword g=0; g < N_gaus; ++g)
{
const eT acc_norm_lhood = (std::max)( final_acc_norm_lhoods[g], std::numeric_limits<eT>::min() );
if(arma_isfinite(acc_norm_lhood) == false) { continue; }
eT* acc_mean_mem = final_acc_means.colptr(g);
for(uword d=0; d < N_dims; ++d)
{
acc_mean_mem[d] /= acc_norm_lhood;
}
const Col<eT> new_mean(acc_mean_mem, N_dims, false, true);
mean_outer = new_mean * new_mean.t();
Mat<eT>& acc_fcov = final_acc_fcovs.slice(g);
acc_fcov /= acc_norm_lhood;
acc_fcov -= mean_outer;
for(uword d=0; d < N_dims; ++d)
{
eT& val = acc_fcov.at(d,d);
if(val < var_floor) { val = var_floor; }
}
if(acc_fcov.is_finite() == false) { continue; }
eT log_det_val = eT(0);
eT log_det_sign = eT(0);
log_det(log_det_val, log_det_sign, acc_fcov);
const bool log_det_ok = ( (arma_isfinite(log_det_val)) && (log_det_sign > eT(0)) );
const bool inv_ok = (log_det_ok) ? bool(auxlib::inv_sympd(mean_outer, acc_fcov)) : bool(false); // mean_outer is used as a junk matrix
if(log_det_ok && inv_ok)
{
hefts_mem[g] = acc_norm_lhood / eT(X.n_cols);
eT* mean_mem = access::rw(means).colptr(g);
for(uword d=0; d < N_dims; ++d)
{
mean_mem[d] = acc_mean_mem[d];
}
Mat<eT>& fcov = access::rw(fcovs).slice(g);
fcov = acc_fcov;
}
}
}
template<typename eT>
inline
void
gmm_full<eT>::em_generate_acc
(
const Mat<eT>& X,
const uword start_index,
const uword end_index,
Mat<eT>& acc_means,
Cube<eT>& acc_fcovs,
Col<eT>& acc_norm_lhoods,
Col<eT>& gaus_log_lhoods,
eT& progress_log_lhood
)
const
{
arma_extra_debug_sigprint();
progress_log_lhood = eT(0);
acc_means.zeros();
acc_fcovs.zeros();
acc_norm_lhoods.zeros();
gaus_log_lhoods.zeros();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const eT* log_hefts_mem = log_hefts.memptr();
eT* gaus_log_lhoods_mem = gaus_log_lhoods.memptr();
for(uword i=start_index; i <= end_index; i++)
{
const eT* x = X.colptr(i);
for(uword g=0; g < N_gaus; ++g)
{
gaus_log_lhoods_mem[g] = internal_scalar_log_p(x, g) + log_hefts_mem[g];
}
eT log_lhood_sum = gaus_log_lhoods_mem[0];
for(uword g=1; g < N_gaus; ++g)
{
log_lhood_sum = log_add_exp(log_lhood_sum, gaus_log_lhoods_mem[g]);
}
progress_log_lhood += log_lhood_sum;
for(uword g=0; g < N_gaus; ++g)
{
const eT norm_lhood = std::exp(gaus_log_lhoods_mem[g] - log_lhood_sum);
acc_norm_lhoods[g] += norm_lhood;
eT* acc_mean_mem = acc_means.colptr(g);
for(uword d=0; d < N_dims; ++d)
{
acc_mean_mem[d] += x[d] * norm_lhood;
}
Mat<eT>& acc_fcov = access::rw(acc_fcovs).slice(g);
// specialised version of acc_fcov += norm_lhood * (xx * xx.t());
for(uword d=0; d < N_dims; ++d)
{
const uword dp1 = d+1;
const eT xd = x[d];
eT* acc_fcov_col_d = acc_fcov.colptr(d) + d;
eT* acc_fcov_row_d = &(acc_fcov.at(d,dp1));
(*acc_fcov_col_d) += norm_lhood * (xd * xd); acc_fcov_col_d++;
for(uword e=dp1; e < N_dims; ++e)
{
const eT val = norm_lhood * (xd * x[e]);
(*acc_fcov_col_d) += val; acc_fcov_col_d++;
(*acc_fcov_row_d) += val; acc_fcov_row_d += N_dims;
}
}
}
}
progress_log_lhood /= eT((end_index - start_index) + 1);
}
template<typename eT>
inline
void
gmm_full<eT>::em_fix_params(const eT var_floor)
{
arma_extra_debug_sigprint();
const uword N_dims = means.n_rows;
const uword N_gaus = means.n_cols;
const eT var_ceiling = std::numeric_limits<eT>::max();
for(uword g=0; g < N_gaus; ++g)
{
Mat<eT>& fcov = access::rw(fcovs).slice(g);
for(uword d=0; d < N_dims; ++d)
{
eT& var_val = fcov.at(d,d);
if(var_val < var_floor ) { var_val = var_floor; }
else if(var_val > var_ceiling) { var_val = var_ceiling; }
else if(arma_isnan(var_val) ) { var_val = eT(1); }
}
}
eT* hefts_mem = access::rw(hefts).memptr();
for(uword g1=0; g1 < N_gaus; ++g1)
{
if(hefts_mem[g1] > eT(0))
{
const eT* means_colptr_g1 = means.colptr(g1);
for(uword g2=(g1+1); g2 < N_gaus; ++g2)
{
if( (hefts_mem[g2] > eT(0)) && (std::abs(hefts_mem[g1] - hefts_mem[g2]) <= std::numeric_limits<eT>::epsilon()) )
{
const eT dist = distance<eT,1>::eval(N_dims, means_colptr_g1, means.colptr(g2), means_colptr_g1);
if(dist == eT(0)) { hefts_mem[g2] = eT(0); }
}
}
}
}
const eT heft_floor = std::numeric_limits<eT>::min();
const eT heft_initial = eT(1) / eT(N_gaus);
for(uword i=0; i < N_gaus; ++i)
{
eT& heft_val = hefts_mem[i];
if(heft_val < heft_floor) { heft_val = heft_floor; }
else if(heft_val > eT(1) ) { heft_val = eT(1); }
else if(arma_isnan(heft_val) ) { heft_val = heft_initial; }
}
const eT heft_sum = accu(hefts);
if((heft_sum < (eT(1) - Datum<eT>::eps)) || (heft_sum > (eT(1) + Datum<eT>::eps))) { access::rw(hefts) /= heft_sum; }
}
} // namespace gmm_priv
//! @}