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Initial commit with file writing and create mode working for atoms

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Alex 2019-11-25 18:19:25 -05:00
parent 624886bbe9
commit 8217e8b51c
15 changed files with 2465 additions and 271 deletions
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132
src/subroutines.f90
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@ -1,13 +1,12 @@
module subroutines
use precision_comm_module
use parameters
use functions
implicit none
integer :: allostat, deallostat
public
contains
!This subroutine is just used to break the code and exit on an error
subroutine read_error_check(para, loc)
@ -18,7 +17,132 @@ module subroutines
print *, "Read error in ", trim(loc), " because of ", para
stop "Exit with error"
end if
end subroutine
subroutine matrix_inverse(a, n, a_inv)
integer :: i, j, k, piv_loc
integer, intent(in) :: n
real(kind = dp) :: coeff, sum_l, sum_u
real(kind = dp), dimension(n) :: b, x, y, b_piv
real(kind = dp), dimension(n, n) :: l, u, p
real(kind = dp), dimension(n, n), intent(in) :: a
real(kind = dp), dimension(n, n), intent(out) :: a_inv
real(kind = dp), allocatable :: v(:), u_temp(:), l_temp(:), p_temp(:)
l(:, :) = identity_mat(n)
u(:, :) = a(:, :)
p(:, :) = identity_mat(n)
!LU decomposition with partial pivoting
do j = 1, n-1
allocate(v(n-j+1), stat = allostat)
if(allostat /=0 ) then
print *, 'Fail to allocate v in matrix_inverse'
stop
end if
v(:) = u(j:n, j)
if(maxval(abs(v)) < lim_zero) then
print *, 'Fail to inverse matrix', a
stop
end if
piv_loc = maxloc(abs(v), 1)
deallocate(v, stat = deallostat)
if(deallostat /=0 ) then
print *, 'Fail to deallocate v in matrix_inverse'
stop
end if
!partial pivoting
if(piv_loc /= 1) then
allocate( u_temp(n-j+1), p_temp(n), stat = allostat)
if(allostat /=0 ) then
print *, 'Fail to allocate p_temp and/or u_temp in matrix_inverse'
stop
end if
u_temp(:) = u(j, j:n)
u(j, j:n) = u(piv_loc+j-1, j:n)
u(piv_loc+j-1, j:n) = u_temp(:)
p_temp(:) = p(j, :)
p(j, :) = p(piv_loc+j-1, :)
p(piv_loc+j-1, :) = p_temp(:)
deallocate( u_temp, p_temp, stat = deallostat)
if(deallostat /=0 ) then
print *, 'Fail to deallocate p_temp and/or u_temp in matrix_inverse'
stop
end if
if(j > 1) then
allocate( l_temp(j-1), stat = allostat)
if(allostat /= 0) then
print *, 'Fail to allocate l_temp in matrix_inverse'
stop
end if
l_temp(:) = l(j, 1:j-1)
l(j, 1:j-1) = l(piv_loc+j-1, 1:j-1)
l(piv_loc+j-1, 1:j-1) = l_temp(:)
deallocate( l_temp, stat = deallostat)
if(deallostat /=0 ) then
print *, 'Fail to deallocate l_temp in matrix_inverse'
stop
end if
end if
end if
!LU decomposition
do i = j+1, n
coeff = u(i, j)/u(j, j)
l(i, j) = coeff
u(i, j:n) = u(i, j:n)-coeff*u(j, j:n)
end do
end do
a_inv(:, :) = 0.0_dp
do j = 1, n
b(:) = 0.0_dp
b(j) = 1.0_dp
b_piv(:) = matmul(p, b)
!Now we have LUx = b_piv
!the first step is to solve y from Ly = b_piv
!forward substitution
do i = 1, n
if(i == 1) then
y(i) = b_piv(i)/l(i, i)
else
sum_l = 0
do k = 1, i-1
sum_l = sum_l+l(i, k)*y(k)
end do
y(i) = (b_piv(i)-sum_l)/l(i, i)
end if
end do
!then we solve x from ux = y
!backward subsitution
do i = n, 1, -1
if(i == n) then
x(i) = y(i)/u(i, i)
else
sum_u = 0
do k = i+1, n
sum_u = sum_u+u(i, k)*x(k)
end do
x(i) = (y(i)-sum_u)/u(i, i)
end if
end do
!put x into j column of a_inv
a_inv(:, j) = x(:)
end do
return
end subroutine matrix_inverse
end module subroutines