linsys_routines.f90 File Reference

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Functions/Subroutines
subroutine	solvelinearsystem (A, b, x, n)

Function/Subroutine Documentation

solvelinearsystem()

subroutine solvelinearsystem	(	real, dimension(n, n), intent(inout)	A,
		real, dimension(n), intent(inout)	b,
		real, dimension(n), intent(out)	x,
		integer, intent(in)	n
	)

Definition at line 35 of file linsys_routines.f90.

    implicit none
    integer, intent(in) :: n
    real, dimension(n, n), intent(inout) :: A
    real, dimension(n), intent(inout) :: b
    real, dimension(n), intent(out) :: x
    real :: factor
    integer :: i, j, k
 
    ! Forward elimination
    do k = 1, n - 1
        do i = k + 1, n
            factor = a(i, k)/a(k, k)
            a(i, k + 1:n) = a(i, k + 1:n) - factor*a(k, k + 1:n)
            b(i) = b(i) - factor*b(k)
        end do
    end do
 
    ! Back substitution
    x(n) = b(n)/a(n, n)
    do i = n - 1, 1, -1
        x(i) = (b(i) - dot_product(a(i, i + 1:n), x(i + 1:n)))/a(i, i)
    end do