inline void for_cons(const blitz::Array<T,n> & M, bool check_order){
need_copy = (!(M.isStorageContiguous()));
if (check_order) for (int i=0; i<n;i++) need_copy = (need_copy || (M.ordering(i)!=i));
#ifdef DEBUG_REF_WARNING
if (need_copy) std::cout<<"WARNING : REF : COPY NEEDED. Performance will be degraded"<<std::endl;
#endif
Mref = (blitz::Array<T,n> *)&M;
// The copy has the same shape but is ordered like a fortran array
if (need_copy) {Mcopy.resize(M.shape());Mcopy=M;}
}
blitz::Array<double,1> bob::example::library::reverse (const blitz::Array<double,1>& array){
// create new array in the desired shape
blitz::Array<double,1> retval(array.shape());
// copy data
for (int i = 0, j = array.extent(0)-1; i < array.extent(0); ++i, --j){
retval(j) = array(i);
}
// return the copied data
return retval;
}
void bob::math::eig_(const blitz::Array<double,2>& A,
blitz::Array<std::complex<double>,2>& V,
blitz::Array<std::complex<double>,1>& D)
{
// Size variable
const int N = A.extent(0);
// Prepares to call LAPACK function
// Initialises LAPACK variables
const char jobvl = 'N'; // Do NOT compute left eigen-vectors
const char jobvr = 'V'; // Compute right eigen-vectors
int info = 0;
const int lda = N;
const int ldvr = N;
double VL = 0; // notice we don't compute the left eigen-values
const int ldvl = 1;
// Initialises LAPACK arrays
blitz::Array<double,2> A_lapack = bob::core::array::ccopy(const_cast<blitz::Array<double,2>&>(A).transpose(1,0));
// temporary arrays to receive LAPACK's eigen-values and eigen-vectors
blitz::Array<double,1> WR(D.shape()); //real part
blitz::Array<double,1> WI(D.shape()); //imaginary part
blitz::Array<double,2> VR(A.shape()); //right eigen-vectors
// Calls the LAPACK function
// A/ Queries the optimal size of the working arrays
const int lwork_query = -1;
double work_query;
dgeev_( &jobvl, &jobvr, &N, A_lapack.data(), &lda, WR.data(), WI.data(),
&VL, &ldvl, VR.data(), &ldvr, &work_query, &lwork_query, &info);
// B/ Computes the eigenvalue decomposition
const int lwork = static_cast<int>(work_query);
boost::shared_array<double> work(new double[lwork]);
dgeev_( &jobvl, &jobvr, &N, A_lapack.data(), &lda, WR.data(), WI.data(),
&VL, &ldvl, VR.data(), &ldvr, work.get(), &lwork, &info);
// Checks info variable
if (info != 0) {
throw std::runtime_error("the QR algorithm failed to compute all the eigenvalues, and no eigenvectors have been computed.");
}
// Copy results back from WR, WI => D
blitz::real(D) = WR;
blitz::imag(D) = WI;
// Copy results back from VR => V, with two rules:
// 1) If the j-th eigenvalue is real, then v(j) = VR(:,j), the j-th column of
// VR.
// 2) If the j-th and (j+1)-st eigenvalues form a complex conjugate pair,
// then v(j) = VR(:,j) + i*VR(:,j+1) and v(j+1) = VR(:,j) - i*VR(:,j+1).
blitz::Range a = blitz::Range::all();
int i=0;
while (i<N) {
if (std::imag(D(i)) == 0.) { //real eigen-value, consume 1
blitz::real(V(a,i)) = VR(i,a);
blitz::imag(V(a,i)) = 0.;
++i;
}
else { //complex eigen-value, consume 2
blitz::real(V(a,i)) = VR(i,a);
blitz::imag(V(a,i)) = VR(i+1,a);
blitz::real(V(a,i+1)) = VR(i,a);
blitz::imag(V(a,i+1)) = -VR(i+1,a);
i += 2;
}
}
}
void bob::math::eigSym_(const blitz::Array<double,2>& A, const blitz::Array<double,2>& B,
blitz::Array<double,2>& V, blitz::Array<double,1>& D)
{
// Size variable
const int N = A.extent(0);
// Prepares to call LAPACK function
// Initialises LAPACK variables
const int itype = 1;
const char jobz = 'V'; // Get both the eigenvalues and the eigenvectors
const char uplo = 'U';
int info = 0;
const int lda = N;
const int ldb = N;
// Initialises LAPACK arrays
blitz::Array<double,2> A_blitz_lapack;
// Tries to use V directly
blitz::Array<double,2> Vt = V.transpose(1,0);
const bool V_direct_use = bob::core::array::isCZeroBaseContiguous(Vt);
if (V_direct_use)
{
A_blitz_lapack.reference(Vt);
// Ugly fix for non-const transpose
A_blitz_lapack = const_cast<blitz::Array<double,2>&>(A).transpose(1,0);
}
else
// Ugly fix for non-const transpose
A_blitz_lapack.reference(
bob::core::array::ccopy(const_cast<blitz::Array<double,2>&>(A).transpose(1,0)));
double *A_lapack = A_blitz_lapack.data();
// Ugly fix for non-const transpose
blitz::Array<double,2> B_blitz_lapack(
bob::core::array::ccopy(const_cast<blitz::Array<double,2>&>(B).transpose(1,0)));
double *B_lapack = B_blitz_lapack.data();
blitz::Array<double,1> D_blitz_lapack;
const bool D_direct_use = bob::core::array::isCZeroBaseContiguous(D);
if (D_direct_use)
D_blitz_lapack.reference(D);
else
D_blitz_lapack.resize(D.shape());
double *D_lapack = D_blitz_lapack.data();
// Calls the LAPACK function
// A/ Queries the optimal size of the working arrays
const int lwork_query = -1;
double work_query;
const int liwork_query = -1;
int iwork_query;
dsygvd_( &itype, &jobz, &uplo, &N, A_lapack, &lda, B_lapack, &ldb, D_lapack,
&work_query, &lwork_query, &iwork_query, &liwork_query, &info);
// B/ Computes the generalized eigenvalue decomposition
const int lwork = static_cast<int>(work_query);
boost::shared_array<double> work(new double[lwork]);
const int liwork = static_cast<int>(iwork_query);
boost::shared_array<int> iwork(new int[liwork]);
dsygvd_( &itype, &jobz, &uplo, &N, A_lapack, &lda, B_lapack, &ldb, D_lapack,
work.get(), &lwork, iwork.get(), &liwork, &info);
// Checks info variable
if (info != 0)
throw std::runtime_error("The LAPACK function 'dsygvd' returned a non-zero value. This might be caused by a non-positive definite B matrix.");
// Copy singular vectors back to V if required
if (!V_direct_use)
V = A_blitz_lapack.transpose(1,0);
// Copy result back to sigma if required
if (!D_direct_use)
D = D_blitz_lapack;
}
