utils.f90 Source File

submodule(specialmatrices_toeplitz) toeplitz_utilities
   implicit none(type, external)
contains
   module procedure dense_rdp
      integer(ilp) :: i, j, m, n
      real(dp), allocatable :: t(:)
      m = A%m ; n = A%n ; allocate(t(-(n-1):m-1)) ; allocate(B(m, n))
      t(:-1) = A%vr(n:2:-1)
      t(0:) = A%vc
      do concurrent(i=1:m, j=1:n)
         B(i, j) = t(i-j)
      enddo
   end procedure

   module procedure transpose_rdp
      B = Toeplitz(A%vr, A%vc)
   end procedure

   module procedure size_rdp
      if (present(dim)) then
         select case(dim)
            case (1)
               arr_size = A%m
            case (2)
               arr_size = A%n
            case default
               error stop "Matrix has only two dimensions."
         end select
      else
         arr_size = A%m * A%n
      endif
   end procedure

   module procedure shape_rdp
      arr_shape = [A%m, A%n]
   end procedure

   module procedure scalar_multiplication_rdp
      B = Toeplitz(alpha*A%vc, alpha*A%vr)
   end procedure

   module procedure scalar_multiplication_bis_rdp
      B = Toeplitz(alpha*A%vc, alpha*A%vr)
   end procedure

   module procedure Toeplitz2Circulant
      real(dp), allocatable :: c_vec(:)
      integer(ilp) :: m, n
      m = T%m ; n = T%n ; allocate(c_vec(m+n))
      c_vec(:m) = T%vc ; c_vec(m+1:) = cshift(T%vr(n:1:-1), -1)
      C = Circulant(c_vec)
   end procedure
end submodule