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armadillo-code/include/armadillo_bits/fn_trace.hpp
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2020-10-20 18:40:30 +10:00

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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 fn_trace
//! @{
template<typename T1>
arma_warn_unused
inline
typename T1::elem_type
trace(const Base<typename T1::elem_type, T1>& X)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const Proxy<T1> P(X.get_ref());
const uword N = (std::min)(P.get_n_rows(), P.get_n_cols());
eT val1 = eT(0);
eT val2 = eT(0);
uword i,j;
for(i=0, j=1; j<N; i+=2, j+=2)
{
val1 += P.at(i,i);
val2 += P.at(j,j);
}
if(i < N)
{
val1 += P.at(i,i);
}
return val1 + val2;
}
template<typename T1>
arma_warn_unused
inline
typename T1::elem_type
trace(const Op<T1, op_diagmat>& X)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const diagmat_proxy<T1> A(X.m);
const uword N = (std::min)(A.n_rows, A.n_cols);
eT val = eT(0);
for(uword i=0; i<N; ++i)
{
val += A[i];
}
return val;
}
//! speedup for trace(A*B); non-complex elements
template<typename T1, typename T2>
arma_warn_unused
inline
typename enable_if2< is_cx<typename T1::elem_type>::no, typename T1::elem_type>::result
trace(const Glue<T1, T2, glue_times>& X)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const partial_unwrap<T1> tmp1(X.A);
const partial_unwrap<T2> tmp2(X.B);
const typename partial_unwrap<T1>::stored_type& A = tmp1.M;
const typename partial_unwrap<T2>::stored_type& B = tmp2.M;
const bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
const eT alpha = use_alpha ? (tmp1.get_val() * tmp2.get_val()) : eT(0);
arma_debug_assert_trans_mul_size< partial_unwrap<T1>::do_trans, partial_unwrap<T2>::do_trans >(A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");
if( (A.n_elem == 0) || (B.n_elem == 0) )
{
return eT(0);
}
const uword A_n_rows = A.n_rows;
const uword A_n_cols = A.n_cols;
const uword B_n_rows = B.n_rows;
const uword B_n_cols = B.n_cols;
eT acc = eT(0);
if( (partial_unwrap<T1>::do_trans == false) && (partial_unwrap<T2>::do_trans == false) )
{
const uword N = (std::min)(A_n_rows, B_n_cols);
eT acc1 = eT(0);
eT acc2 = eT(0);
for(uword k=0; k < N; ++k)
{
const eT* B_colptr = B.colptr(k);
// condition: A_n_cols = B_n_rows
uword j;
for(j=1; j < A_n_cols; j+=2)
{
const uword i = (j-1);
const eT tmp_i = B_colptr[i];
const eT tmp_j = B_colptr[j];
acc1 += A.at(k, i) * tmp_i;
acc2 += A.at(k, j) * tmp_j;
}
const uword i = (j-1);
if(i < A_n_cols)
{
acc1 += A.at(k, i) * B_colptr[i];
}
}
acc = (acc1 + acc2);
}
else
if( (partial_unwrap<T1>::do_trans == true ) && (partial_unwrap<T2>::do_trans == false) )
{
const uword N = (std::min)(A_n_cols, B_n_cols);
for(uword k=0; k < N; ++k)
{
const eT* A_colptr = A.colptr(k);
const eT* B_colptr = B.colptr(k);
// condition: A_n_rows = B_n_rows
acc += op_dot::direct_dot(A_n_rows, A_colptr, B_colptr);
}
}
else
if( (partial_unwrap<T1>::do_trans == false) && (partial_unwrap<T2>::do_trans == true ) )
{
const uword N = (std::min)(A_n_rows, B_n_rows);
for(uword k=0; k < N; ++k)
{
// condition: A_n_cols = B_n_cols
for(uword i=0; i < A_n_cols; ++i)
{
acc += A.at(k,i) * B.at(k,i);
}
}
}
else
if( (partial_unwrap<T1>::do_trans == true ) && (partial_unwrap<T2>::do_trans == true ) )
{
const uword N = (std::min)(A_n_cols, B_n_rows);
for(uword k=0; k < N; ++k)
{
const eT* A_colptr = A.colptr(k);
// condition: A_n_rows = B_n_cols
for(uword i=0; i < A_n_rows; ++i)
{
acc += A_colptr[i] * B.at(k,i);
}
}
}
return (use_alpha) ? (alpha * acc) : acc;
}
//! speedup for trace(A*B); complex elements
template<typename T1, typename T2>
arma_warn_unused
inline
typename enable_if2< is_cx<typename T1::elem_type>::yes, typename T1::elem_type>::result
trace(const Glue<T1, T2, glue_times>& X)
{
arma_extra_debug_sigprint();
typedef typename T1::pod_type T;
typedef typename T1::elem_type eT;
const partial_unwrap<T1> tmp1(X.A);
const partial_unwrap<T2> tmp2(X.B);
const typename partial_unwrap<T1>::stored_type& A = tmp1.M;
const typename partial_unwrap<T2>::stored_type& B = tmp2.M;
const bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
const eT alpha = use_alpha ? (tmp1.get_val() * tmp2.get_val()) : eT(0);
arma_debug_assert_trans_mul_size< partial_unwrap<T1>::do_trans, partial_unwrap<T2>::do_trans >(A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");
if( (A.n_elem == 0) || (B.n_elem == 0) )
{
return eT(0);
}
const uword A_n_rows = A.n_rows;
const uword A_n_cols = A.n_cols;
const uword B_n_rows = B.n_rows;
const uword B_n_cols = B.n_cols;
eT acc = eT(0);
if( (partial_unwrap<T1>::do_trans == false) && (partial_unwrap<T2>::do_trans == false) )
{
const uword N = (std::min)(A_n_rows, B_n_cols);
T acc_real = T(0);
T acc_imag = T(0);
for(uword k=0; k < N; ++k)
{
const eT* B_colptr = B.colptr(k);
// condition: A_n_cols = B_n_rows
for(uword i=0; i < A_n_cols; ++i)
{
// acc += A.at(k, i) * B_colptr[i];
const std::complex<T>& xx = A.at(k, i);
const std::complex<T>& yy = B_colptr[i];
const T a = xx.real();
const T b = xx.imag();
const T c = yy.real();
const T d = yy.imag();
acc_real += (a*c) - (b*d);
acc_imag += (a*d) + (b*c);
}
}
acc = std::complex<T>(acc_real, acc_imag);
}
else
if( (partial_unwrap<T1>::do_trans == true) && (partial_unwrap<T2>::do_trans == false) )
{
const uword N = (std::min)(A_n_cols, B_n_cols);
T acc_real = T(0);
T acc_imag = T(0);
for(uword k=0; k < N; ++k)
{
const eT* A_colptr = A.colptr(k);
const eT* B_colptr = B.colptr(k);
// condition: A_n_rows = B_n_rows
for(uword i=0; i < A_n_rows; ++i)
{
// acc += std::conj(A_colptr[i]) * B_colptr[i];
const std::complex<T>& xx = A_colptr[i];
const std::complex<T>& yy = B_colptr[i];
const T a = xx.real();
const T b = xx.imag();
const T c = yy.real();
const T d = yy.imag();
// take into account the complex conjugate of xx
acc_real += (a*c) + (b*d);
acc_imag += (a*d) - (b*c);
}
}
acc = std::complex<T>(acc_real, acc_imag);
}
else
if( (partial_unwrap<T1>::do_trans == false) && (partial_unwrap<T2>::do_trans == true) )
{
const uword N = (std::min)(A_n_rows, B_n_rows);
T acc_real = T(0);
T acc_imag = T(0);
for(uword k=0; k < N; ++k)
{
// condition: A_n_cols = B_n_cols
for(uword i=0; i < A_n_cols; ++i)
{
// acc += A.at(k,i) * std::conj(B.at(k,i));
const std::complex<T>& xx = A.at(k, i);
const std::complex<T>& yy = B.at(k, i);
const T a = xx.real();
const T b = xx.imag();
const T c = yy.real();
const T d = -yy.imag(); // take the conjugate
acc_real += (a*c) - (b*d);
acc_imag += (a*d) + (b*c);
}
}
acc = std::complex<T>(acc_real, acc_imag);
}
else
if( (partial_unwrap<T1>::do_trans == true) && (partial_unwrap<T2>::do_trans == true) )
{
const uword N = (std::min)(A_n_cols, B_n_rows);
T acc_real = T(0);
T acc_imag = T(0);
for(uword k=0; k < N; ++k)
{
const eT* A_colptr = A.colptr(k);
// condition: A_n_rows = B_n_cols
for(uword i=0; i < A_n_rows; ++i)
{
// acc += std::conj(A_colptr[i]) * std::conj(B.at(k,i));
const std::complex<T>& xx = A_colptr[i];
const std::complex<T>& yy = B.at(k, i);
const T a = xx.real();
const T b = -xx.imag(); // take the conjugate
const T c = yy.real();
const T d = -yy.imag(); // take the conjugate
acc_real += (a*c) - (b*d);
acc_imag += (a*d) + (b*c);
}
}
acc = std::complex<T>(acc_real, acc_imag);
}
return (use_alpha) ? eT(alpha * acc) : eT(acc);
}
//! trace of sparse object; generic version
template<typename T1>
arma_warn_unused
inline
typename T1::elem_type
trace(const SpBase<typename T1::elem_type,T1>& expr)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const SpProxy<T1> P(expr.get_ref());
const uword N = (std::min)(P.get_n_rows(), P.get_n_cols());
eT acc = eT(0);
if( (is_SpMat<typename SpProxy<T1>::stored_type>::value) && (P.get_n_nonzero() >= 5*N) )
{
const unwrap_spmat<typename SpProxy<T1>::stored_type> U(P.Q);
const SpMat<eT>& X = U.M;
for(uword i=0; i < N; ++i)
{
acc += X.at(i,i); // use binary search
}
}
else
{
typename SpProxy<T1>::const_iterator_type it = P.begin();
const uword P_n_nz = P.get_n_nonzero();
for(uword i=0; i < P_n_nz; ++i)
{
if(it.row() == it.col()) { acc += (*it); }
++it;
}
}
return acc;
}
//! trace of sparse object; speedup for trace(A + B)
template<typename T1, typename T2>
arma_warn_unused
inline
typename T1::elem_type
trace(const SpGlue<T1, T2, spglue_plus>& expr)
{
arma_extra_debug_sigprint();
const unwrap_spmat<T1> UA(expr.A);
const unwrap_spmat<T2> UB(expr.B);
arma_debug_assert_same_size(UA.M.n_rows, UA.M.n_cols, UB.M.n_rows, UB.M.n_cols, "addition");
return (trace(UA.M) + trace(UB.M));
}
//! trace of sparse object; speedup for trace(A - B)
template<typename T1, typename T2>
arma_warn_unused
inline
typename T1::elem_type
trace(const SpGlue<T1, T2, spglue_minus>& expr)
{
arma_extra_debug_sigprint();
const unwrap_spmat<T1> UA(expr.A);
const unwrap_spmat<T2> UB(expr.B);
arma_debug_assert_same_size(UA.M.n_rows, UA.M.n_cols, UB.M.n_rows, UB.M.n_cols, "subtraction");
return (trace(UA.M) - trace(UB.M));
}
//! trace of sparse object; speedup for trace(A % B)
template<typename T1, typename T2>
arma_warn_unused
inline
typename T1::elem_type
trace(const SpGlue<T1, T2, spglue_schur>& expr)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const unwrap_spmat<T1> UA(expr.A);
const unwrap_spmat<T2> UB(expr.B);
const SpMat<eT>& A = UA.M;
const SpMat<eT>& B = UB.M;
arma_debug_assert_same_size(A.n_rows, A.n_cols, B.n_rows, B.n_cols, "element-wise multiplication");
const uword N = (std::min)(A.n_rows, A.n_cols);
eT acc = eT(0);
for(uword i=0; i<N; ++i)
{
acc += A.at(i,i) * B.at(i,i);
}
return acc;
}
//! trace of sparse object; speedup for trace(A*B)
template<typename T1, typename T2>
arma_warn_unused
inline
typename T1::elem_type
trace(const SpGlue<T1, T2, spglue_times>& expr)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
// better-than-nothing implementation
const unwrap_spmat<T1> UA(expr.A);
const unwrap_spmat<T2> UB(expr.B);
const SpMat<eT>& A = UA.M;
const SpMat<eT>& B = UB.M;
arma_debug_assert_mul_size(A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");
if( (A.n_nonzero == 0) || (B.n_nonzero == 0) )
{
return eT(0);
}
const uword N = (std::min)(A.n_rows, B.n_cols);
eT acc = eT(0);
// TODO: the threshold may need tuning for complex matrices
if( (A.n_nonzero >= 5*N) || (B.n_nonzero >= 5*N) )
{
for(uword k=0; k < N; ++k)
{
typename SpMat<eT>::const_col_iterator B_it = B.begin_col_no_sync(k);
typename SpMat<eT>::const_col_iterator B_it_end = B.end_col_no_sync(k);
while(B_it != B_it_end)
{
const eT B_val = (*B_it);
const uword i = B_it.row();
acc += A.at(k,i) * B_val;
++B_it;
}
}
}
else
{
const SpMat<eT> AB = A * B;
acc = trace(AB);
}
return acc;
}
//! trace of sparse object; speedup for trace(A.t()*B); non-complex elements
template<typename T1, typename T2>
arma_warn_unused
inline
typename enable_if2< is_cx<typename T1::elem_type>::no, typename T1::elem_type>::result
trace(const SpGlue<SpOp<T1, spop_htrans>, T2, spglue_times>& expr)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const unwrap_spmat<T1> UA(expr.A.m);
const unwrap_spmat<T2> UB(expr.B);
const SpMat<eT>& A = UA.M;
const SpMat<eT>& B = UB.M;
// NOTE: deliberately swapped A.n_rows and A.n_cols to take into account the requested transpose operation
arma_debug_assert_mul_size(A.n_cols, A.n_rows, B.n_rows, B.n_cols, "matrix multiplication");
if( (A.n_nonzero == 0) || (B.n_nonzero == 0) )
{
return eT(0);
}
const uword N = (std::min)(A.n_cols, B.n_cols);
eT acc = eT(0);
if( (A.n_nonzero >= 5*N) || (B.n_nonzero >= 5*N) )
{
for(uword k=0; k < N; ++k)
{
typename SpMat<eT>::const_col_iterator B_it = B.begin_col_no_sync(k);
typename SpMat<eT>::const_col_iterator B_it_end = B.end_col_no_sync(k);
while(B_it != B_it_end)
{
const eT B_val = (*B_it);
const uword i = B_it.row();
acc += A.at(i,k) * B_val;
++B_it;
}
}
}
else
{
const SpMat<eT> AtB = A.t() * B;
acc = trace(AtB);
}
return acc;
}
//! trace of sparse object; speedup for trace(A.t()*B); complex elements
template<typename T1, typename T2>
arma_warn_unused
inline
typename enable_if2< is_cx<typename T1::elem_type>::yes, typename T1::elem_type>::result
trace(const SpGlue<SpOp<T1, spop_htrans>, T2, spglue_times>& expr)
{
arma_extra_debug_sigprint();
typedef typename T1::elem_type eT;
const unwrap_spmat<T1> UA(expr.A.m);
const unwrap_spmat<T2> UB(expr.B);
const SpMat<eT>& A = UA.M;
const SpMat<eT>& B = UB.M;
// NOTE: deliberately swapped A.n_rows and A.n_cols to take into account the requested transpose operation
arma_debug_assert_mul_size(A.n_cols, A.n_rows, B.n_rows, B.n_cols, "matrix multiplication");
if( (A.n_nonzero == 0) || (B.n_nonzero == 0) )
{
return eT(0);
}
const uword N = (std::min)(A.n_cols, B.n_cols);
eT acc = eT(0);
// TODO: the threshold may need tuning for complex matrices
if( (A.n_nonzero >= 5*N) || (B.n_nonzero >= 5*N) )
{
for(uword k=0; k < N; ++k)
{
typename SpMat<eT>::const_col_iterator B_it = B.begin_col_no_sync(k);
typename SpMat<eT>::const_col_iterator B_it_end = B.end_col_no_sync(k);
while(B_it != B_it_end)
{
const eT B_val = (*B_it);
const uword i = B_it.row();
acc += std::conj(A.at(i,k)) * B_val;
++B_it;
}
}
}
else
{
const SpMat<eT> AtB = A.t() * B;
acc = trace(AtB);
}
return acc;
}
//! @}