QR decomposition: Difference between revisions

implicit none

integer, parameter :: n = 4

real(8) :: q(n, n), r(n, n), qr(n, n), id(n, n), tau(n)

integer, parameter :: lwork = 1024

real(8) :: work(lwork)

integer :: info, i, j

q = durer

call dgeqrf(n, n, q, n, tau, work, lwork, info)

r = 0d0

forall (i = 1:n, j = 1:n, j >= i) r(i, j) = q(i, j)

call dorgqr(n, n, n, q, n, tau, work, lwork, info)

qr = matmul(q, r)

id = matmul(q, transpose(q))

call show(4, durer, "A")

call show(4, q, "Q")

integer :: n, i

real(8) :: a(n, n)

print *, s

do i = 1, n

print 1, a(i, :)

end do

end subroutine