Check bounds changes variables - fortran

Question

I'm porting a program that I use in a chemistry classroom from Matlab (very forgiving) to Fortran (err, not so much). The problem I see is that if I include print statements in 1 subroutine, my code returns significantly different values than if I don't (the ones with the print statement included are correct).
After reading stack overflow, I removed the print statement, recompiled with gfortran and fcheck='bounds', and my program returned the correct results, and no errors during compile.
The subroutines stored in a module Basis_Subs, and called from the main program, which I've posted below. The problem appears in the 4 dimensional matrix Gabcd(nb,nb,nb,nb) which is constructed using the subroutine Build_Electron_Repulsion from the Basis_Subs module. That subroutine calculates the matrix elements of Gabcd, and uses 1 internal helper functions, Rntuv, and 1 internal subroutine Gprod_1D, both of which are also stored in the Basis_Subs module.
These functions/routines are used in another section of the program, and that portion of the program doesn't show any errors or funny array behavior. That leads me to think the problem must either be in Build_Electron_Repulsion, how I'm calling Build_Electron_Repulsion or how I'm calling the the helper functions from inside Build_Electron_Repulsion.
I've posted the main program, and the subroutines for Build_Electron_Repulsion, gprod_1D, and the function Rntuv. What I'm really wondering is if you have any tips on tracking down where the error might be.
I'm using a pico style editor and gfortran.
Main Program, Z.f08
program HF
use typedefs
use Basis_Subs
use SCF_Mod
implicit none
real(dp) :: output, start, finish
integer (kind=4) :: IFLAG , i, N, nb,j,k,l,natom
integer, allocatable, dimension(:) :: Z
real(dp), allocatable, dimension(:,:) :: AL, S,T, VAB, H0
real(dp), allocatable, dimension(:,:,:,:) :: Gabcd
real(dp), dimension(maxl) :: Ex=0
real(dp) :: Energy, Nuc
type(primitive) :: g1, Build_Primitive
type(Basis) :: b1
type(Basis), dimension(100) :: bases
character(LEN=20) :: fname
print *, 'Input the filename'
read (*,*), fname
open(unit=12, file=fname)
read(12,*) natom
allocate(Z(natom))
allocate(AL(natom,3))
read(12,*) Z
do i=1, natom
read(12,*) AL(i,1), AL(i,2), AL(i,3)
end do
print *, 'Atomic Coorinates = ', AL
print *, 'Z in the main routine = ', Z
call cpu_time(start)
%Calculate the energies that don't depend on electrons
call Nuclear_Repulsion(natom, Z, AL, Nuc)
N=Sum(Z)
%Build the atom specific basis set
call Build_Bases(Z, AL, nb, bases)
%Using nb, from Build_Basis, allocate matrices
allocate(S(nb,nb))
allocate(T(nb,nb))
allocate(VAB(nb,nb))
allocate(Gabcd(nb,nb,nb,nb))
call Build_Overlap(bases, nb, S)
call Build_Kinetic(bases, nb, T)
call Build_Nuclear_Attraction(Z, AL, bases, nb, VAB)
H0 = T+VAB
call Build_Electron_Repulsion(bases, nb, Gabcd)
call cpu_time(finish)
print *, 'Total time for Matrix Elements= ', finish - start
call SCF(N, nb, H0, S, Gabcd, Nuc, Energy)
end program HF
Build_Electron_Repulsion is located inside the module Basis_Subs:
subroutine Build_Electron_Repulsion(bases, nbases, Gabcd)
!!Calculate the 4 centered electron repulsion integrals. Loop over array of !!basis sets 1:nb 4 times. Each element of basis set is a defined type that !!includes and array of gaussian functions and contraction coefficients !!basis(a)%g(1:nga) and basis(a)%c(1:nga). For each gaussian in each basis set,
!!Calculate int(int(basis(a1)*basis(b1)*basis(c2)*basis(d2)*1/r12 dr1)dr2).
!!Uses helper function Rntuv listed below
implicit none
type(basis), dimension(100), intent(in) :: bases
integer, intent(in) :: nbases
real(dp), dimension(nbases, nbases,nbases,nbases), intent(out) :: Gabcd
integer :: a, b,c,d, nga, ngb, ngc, ngd, index, lx, ly, lz, llx, lly,llz
integer :: llxmax, llymax, llzmax, lxmax, lymax, lzmax, xmax, ymax, zmax
integer :: x, y, z
real(dp) :: p, q, midpoint, PX, PY, PZ, output
real(dp) :: pp, qq, midpoint2, PPX, PPY, PPZ, tmp
real(dp) :: alpha_a, alpha_b, alpha_c, alpha_d, alpha
real(dp) :: ax, ay, az, bx, by, bz, cx,cy,cz, dx,dy,dz
real(dp), dimension(maxl) ::EabX, EabY, EabZ, EcdX, EcdY, EcdZ
real(dp), dimension(2*maxl, 2*maxl, 2*maxl) :: R
R=0
Gabcd=0.0D0
print *, 'Calculating 4 centered integrals'
do a=1, nbases
do b=1, nbases
do c=1, nbases
do d=1, nbases
do nga = 1, bases(a)%n
do ngb = 1, bases(b)%n
alpha_a=bases(a)%g(nga)%alpha
alpha_b=bases(b)%g(ngb)%alpha
p=alpha_a + alpha_b
ax=bases(a)%g(nga)%x
ay=bases(a)%g(nga)%y
az=bases(a)%g(nga)%z
bx=bases(b)%g(ngb)%x
by=bases(b)%g(ngb)%y
bz=bases(b)%g(ngb)%z
PX=(alpha_a*ax + alpha_b*bx)/p
PY=(alpha_a*ay + alpha_b*by)/p
PZ=(alpha_a*az + alpha_b*bz)/p
call gprod_1D(ax, alpha_a, bases(a)%g(nga)%lx, bx, alpha_b, bases(b)%g(ngb)%lx, EabX)
call gprod_1D(ay, alpha_a, bases(a)%g(nga)%ly, by, alpha_b, bases(b)%g(ngb)%ly, EabY)
call gprod_1D(az, alpha_a, bases(a)%g(nga)%lz, bz, alpha_b, bases(b)%g(ngb)%lz, EabZ)
lxmax=bases(a)%g(nga)%lx + bases(b)%g(ngb)%lx
lymax=bases(a)%g(nga)%ly + bases(b)%g(ngb)%ly
lzmax=bases(a)%g(nga)%lz + bases(b)%g(ngb)%lz
do ngc= 1, bases(c)%n
do ngd = 1, bases(d)%n
alpha_c=bases(c)%g(ngc)%alpha
alpha_d=bases(d)%g(ngd)%alpha
pp=alpha_c + alpha_d
cx=bases(c)%g(ngc)%x
cy=bases(c)%g(ngc)%y
cz=bases(c)%g(ngc)%z
dx=bases(d)%g(ngd)%x
dx=bases(d)%g(ngd)%y
dz=bases(d)%g(ngd)%z
PPX=(alpha_c*cx + alpha_d*dx)/pp
PPY=(alpha_c*cy + alpha_d*dy)/pp
PPZ=(alpha_c*cz + alpha_d*dz)/pp
llxmax=bases(c)%g(ngc)%lx + bases(d)%g(ngd)%lx
llymax=bases(c)%g(ngc)%ly + bases(d)%g(ngd)%ly
llzmax=bases(c)%g(ngc)%lz + bases(d)%g(ngd)%lz
call gprod_1D(cx, alpha_c, bases(c)%g(ngc)%lx, dx, alpha_d, bases(d)%g(ngd)%lx, EcdX)
call gprod_1D(cy, alpha_c, bases(c)%g(ngc)%ly, dy, alpha_d, bases(d)%g(ngd)%ly, EcdY)
call gprod_1D(cz, alpha_c, bases(c)%g(ngc)%lz, dz, alpha_d, bases(d)%g(ngd)%lz, EcdZ)
alpha=p*pp/(p+pp)
tmp=0
xmax= lxmax + llxmax
ymax = lymax + llymax
zmax = lzmax + llzmax
do x = 0, xmax
do y =0, ymax
do z=0, zmax
R(x+1,y+1,z+1)=Rntuv(0,x,y,z,alpha, PX, PY, PZ, PPX, PPY, PPZ)
end do
end do
end do
!if (a ==1 .and. b==1 .and. c ==1 .and. d==1) then
! print *,' R = ', R(1,1,1)
!print *, xmax, ymax, zmax
!print *,a,b,c,d,nga,ngb,ngc,ngd, 'R = ', R(1,1,1)
!end if
! if (PZ ==PPZ) then
! ! print *, R(1,1,1)
! output = Rntuv(0,0,0,0,alpha, PX, PY, PZ, PPX, PPY, PPZ)
! print *, output
! print *, a,b,c,d , PY, PPY
!
! end if
do lx = 0, lxmax
do ly = 0, lymax
do lz = 0, lzmax
do llx= 0, llxmax
do lly= 0, llymax
do llz= 0, llzmax
tmp = tmp + EabX(lx+1)*EabY(ly+1)*EabZ(lz+1)*(-1.0D0)**(llx + lly + llz) * &
EcdX(llx+1)*EcdY(lly+1)*EcdZ(llz+1)*R(lx+ llx+1, ly+lly+1, lz+llz+1)
end do
end do
end do
end do
end do
end do
Gabcd(a,b,c,d) = Gabcd(a,b,c,d) + 2.0D0*pi**2.5D0/(p*pp*sqrt(p + pp))*tmp*bases(a)%g(nga)%N &
* bases(b)%g(ngb)%N * bases(c)%g(ngc)%N * bases(d)%g(ngd)%N * bases(a)%c(nga) &
* bases(b)%c(ngb) * bases(c)%c(ngc) * bases(d)%c(ngd)
end do
end do
end do
end do
end do
end do
end do
end do
end subroutine Build_Electron_Repulsion
real(dp) function Rntuv(n, tmax, umax, vmax, p, Px, Py, Pz, Ax, Ay, Az) result(out)
!Rntuv(n, t,u,v,p,P,A)Determine the helper integral Rntuv for the coulomb
!integral of order n, the t,u,v th Hermite polynomial with exponent p
!centered at [Px Py Pz] and charge centered at location [Ax Ay Az];
implicit none
integer, intent(in) :: n, tmax, umax, vmax
real(dp), intent(in) :: Px, Py, Pz, Ax, Ay, Az, p
real(dp) :: PA2, output
real(dp), dimension(n+tmax+umax+vmax+2, tmax+1, umax+1, vmax+1) :: R
integer :: nmax, t, u, v
integer :: i, IFLAG
R=0
nmax = n+ tmax + umax + vmax + 2
PA2 = (Px-Ax)**2.0D0 + (Py-Ay)**2.0D0 + (Pz-Az)**2.0D0
do i = 0, nmax-1
output=Boys(i, p*PA2)
R(i+1,1,1,1)= (-2*p)**(1.0D0*i)*Boys(i, p*PA2)
end do
do t=1, tmax
if (t==1) then
do i=1,nmax-1
R(i,2,1,1)=(Px - Ax)*R(i+1,1,1,1)
end do
else
do i=1,nmax-1
R(i,t+1,1,1)=(t-1)*R(i+1,t-1,1,1)+ (Px-Ax)*R(i+1,t,1,1)
end do
end if
end do
do u = 1,umax
if (u==1) then
do i = 1,nmax-1
R(i,tmax+1,2,1)=(Py-Ay)*R(i+1,tmax+1,1,1)
end do
else
do i = 1,nmax-1
R(i,tmax+1,u+1,1)=(u-1)*R(i+1,tmax+1,u-1,1) + (Py-Ay)*R(i+1,tmax+1,u,1)
end do
end if
end do
do v=1,vmax
if (v==1) then
do i = 1, nmax-1
R(i,tmax+1,umax+1,2)=(Pz-Az)*R(i+1,tmax+1,umax+1,1)
end do
else
do i = 1, nmax-1
R(i,tmax+1,umax+1,v+1)=(v-1)*R(i+1,tmax+1,umax+1,v-1) + (Pz-Az)*R(i+1,tmax+1,umax+1,v)
end do
end if
end do
out = R(n+1,tmax+1,umax+1,vmax+1)
end function Rntuv
subroutine gprod_1D(x1, alpha1, lx1, x2, alpha2, lx2, Ex)
real(dp), intent(in) :: x1, alpha1, x2, alpha2
integer, intent(in) :: lx1, lx2
integer :: tmax, i, j ,t, qint
real(dp) :: p, q, midpoint, weighted_middle, KAB
real(dp), dimension(maxl), intent(inout) :: Ex
real(dp), dimension(maxl, maxl, 2*maxl) ::coefficients
coefficients=0.0D0
tmax=lx1 + lx2
Ex=0
p=alpha1 + alpha2
q=alpha1*alpha2/p
midpoint = x1 - x2
weighted_middle=(alpha1*x1 + alpha2*x2)/p
KAB= e**(-q*midpoint**2.0D0)
coefficients(1,1,1) = KAB
i=0
j=0
do while (i < lx1)
do t= 0, i+j+1
if (t==0) then
coefficients(i+2,j+1,t+1)=(weighted_middle - x1)*coefficients(i+1,j+1,t+1) + (t+1)*coefficients(i+1,j+1,t+2)
else
coefficients(i+2,j+1,t+1)=1/(2*p)*coefficients(i+1,j+1,t) + (weighted_middle-x1)*coefficients(i+1,j+1,t+1) + &
(t+1)*coefficients(i+1,j+1,t+2)
end if
end do
i=i+1
end do
do while (j < lx2)
do t=0, i+j+1
if (t==0) then
coefficients(i+1,j+2,t+1) = (weighted_middle - x2)*coefficients(i+1,j+1,t+1) + (dble(t)+1.0d0)*coefficients(i+1,j+1,t+2)
else
coefficients(i+1,j+2,t+1)=1/(2*p)*coefficients(i+1,j+1,t) + (weighted_middle - x2)*coefficients(i+1,j+1,t+1) + &
(t+1)*coefficients(i+1,j+1,t+2)
end if
end do
j=j+1
end do
do qint=1, i+j+1
Ex(qint) = coefficients(i+1,j+1,qint)
end do
end subroutine gprod_1D