module hei

use sub_solver

implicit none
contains



subroutine heis(f,T,n)

integer, intent(in) :: n

double precision, intent(in) :: f

double precision, dimension(:,:), allocatable :: T

double precision pi,re,L2norm

integer i
pi=3.14159265359

do i=1,50


call BC(n,T)



call gauss_seidel(n,T)

call L2normsolver(n,T,L2norm)



if (abs(L2old-L2norm) .LE. 0.0000001) then

exit

end if


end do

write(*,*)'iteration count',i





end subroutine heis




end module hei


subroutine L2normsolver(n,T,L2norm)

integer, intent(in) :: n
double precision, dimension(:,:), allocatable :: T

integer i,j
double precision errorsum,L2norm,pi,h,x,y

pi=3.14159265359

h=1/n

errorsum=0

!Sums up all the errors

do i=2,n+1
do j=2,n+1

x=(j-1.5)*1/n
y=(i-1.5)*1/n



errorsum=errorsum+(T(i,j)-(cos(pi*x)*sinh(pi*y))/sinh(pi))**2


end do
end do


!L2 norm
L2norm=sqrt(errorsum/(n**2))




end subroutine L2normsolver