Fortran code gives outputs with only certain files - fortran

Question

I have 4 .mtx files that I am reading the values from. Two of them run perfectly when read from with no issues and produce the correct outputs into a .DAT file. However, the last 2 are extremely large files; it appears the code correctly reads from the files and runs, but I get no outputs and no errors when reading from these 2...not even the code timer prints the time. Any help is much appreciated! Here is the code:
program proj2matrixC40
implicit none
integer,parameter::dp=selected_real_kind(15,307)
! Set Global Variables
real(kind=dp), allocatable::Ax(:,:),A(:,:),Iglobal(:,:)
integer::At(1,3)
integer::nnz,w,n,k,ii,ff,kk
real(kind=dp)::t1,t2
call cpu_time(t1)
open(unit=78,file="e40r5000.mtx",status='old')
read(78,*) At
close(unit=78)
nnz = At(1,3)
n = At(1,1)
k = 40
kk = 35
allocate(Ax(nnz+1,3),A(nnz,3),Iglobal(k,k))
open(unit=61,file="e40r5000.mtx",status='old')
do w=1,nnz+1
read(61,*) Ax(w,:)
end do
open (unit = 53, file = "proj2matrixC40points.dat")
do ff=1,k
do ii=1,k
Iglobal(ii,ff) = (ii/ff)*(ff/ii)
end do
end do
A(1:nnz,:) = Ax(2:nnz+1,:)
call Arno(A)
call cpu_time(t2)
print '("Time elapsed = ",f10.8," seconds")', (t2 - t1)
contains
subroutine Arno(a)
real(kind=dp), intent(in)::a(:,:)
real(kind=dp),dimension(k,k)::H
real(kind=dp),dimension(k,k+1)::u,q,qconj
real(kind=dp),dimension(k,1)::x0
integer::j,f
call random_number(x0)
q(:,1) = x0(:,1)/norm2(x0(:,1))
do f=1,k
call spmat(a,q(:,f),u(:,f))
do j=1,f
qconj(j,:) = (q(:,j))
H(j,f) = dot_product(qconj(j,:),u(:,f))
u(:,f) = u(:,f) - H(j,f)*q(:,j)
end do
if (f.lt.k) then
H(f+1,f) = norm2(u(:,f))
if (H(f+1,f)==0) then
print *, "Matrix is reducible"
stop
end if
q(:,f+1) = u(:,f)/H(f+1,f)
end if
if (f==k) then
call qrit(H)
end if
end do
end subroutine
! QR Iteration with Shifts Subroutine
subroutine qrit(a)
real(kind=dp), intent(in)::a(:,:)
real(kind=dp)::sigmak
real(kind=dp),dimension(kk,k)::dia
real(kind=dp),dimension(k,k)::Qfinal,Rfinal,HH
real(kind=dp),dimension(k,k,kk)::H0,needQR
integer::v,z
HH = a
H0(:,:,1) = HH
do v=1,kk
sigmak = H0(k,k,v)
if (v-1==0) then
needQR(:,:,v) = HH - sigmak*Iglobal
else
needQR(:,:,v) = H0(:,:,v-1) - sigmak*Iglobal
end if
call givens2(needQR(:,:,v),Rfinal,Qfinal)
H0(:,:,v) = matmul(Rfinal,Qfinal) + sigmak*Iglobal
do z = 1,k
dia(v,z) = H0(z,z,v)
write(53,*) v," ", dia(v,z) ! Write values to .DAT file
end do
end do
end subroutine
! Sparse Matrix Vector Multiplication Subroutine
subroutine spmat(a,b,c)
real(kind=dp), intent(in)::a(:,:)
real(kind=dp), intent(in), dimension(k,1)::b
real(kind=dp), intent(out), dimension(k,1)::c
integer::m,rowi,columni
real(kind=dp), dimension(k,1)::x,y
x = b
y(:,1) = 0
do m = 1,nnz
rowi = a(m,1)
columni = a(m,2)
y(rowi,1) = y(rowi,1) + a(m,3)*x(columni,1)
end do
c(:,1) = y(:,1)
end subroutine
! QR Factorization Givens Rotations Subroutine
subroutine givens2(a,Rfinal,Qfinal)
real(kind=dp), intent(in)::a(:,:)
real(kind=dp), dimension(k,k,(k*k))::G,QQ
real(kind=dp), dimension(k,k), intent(out)::Rfinal,Qfinal
real(kind=dp), dimension(k,k)::I2,y,aa
real(kind=dp), dimension(1,k)::ek1,ek2
real(kind=dp)::c,s
integer::kt,m,nn,j,i,l,p
m = size(a,1)
nn = size(a,2)
aa = a
i = 1
do kt=1,nn-1
do j=m,kt+1,-1
if (aa(j,kt).eq.0) then
continue
else
ek1(1,:) = 0
ek2(1,:) = 0
do p=1,m
do l=1,m
I2(l,p) = (l/p)*(p/l)
end do
end do
c = aa(kt,kt)/sqrt(aa(kt,kt)**2 + aa(j,kt)**2)
s = aa(j,kt)/sqrt(aa(kt,kt)**2 + aa(j,kt)**2)
ek1(1,kt) = c
ek1(1,j) = s
ek2(1,kt) = -s
ek2(1,j) = c
I2(kt,:) = ek1(1,:)
I2(j,:) = ek2(1,:)
G(:,:,i) = I2
if (i.eq.1) then
QQ(:,:,i) = G(:,:,i)
else
QQ(:,:,i) = matmul(G(:,:,i),QQ(:,:,i-1))
end if
y = matmul(G(:,:,i),aa)
aa = y
if (kt.eq.nn-1) then
if (j.eq.kt+1) then
Qfinal = transpose(QQ(:,:,i))
Rfinal = aa
end if
end if
i = i + 1
end if
end do
end do
end subroutine
end program proj2matrixC40
A couple notes. The line which I put asterisks around (for this question) call mat_print('H',H) can't be deleted otherwise I get the wrong answers (this is strange...thoughts?). Also so your computer won't freeze opening the big files, their names are 'e40r5000.mtx' and 's3dkt3m2.mtx' (these are the two I have issues with). I am using gfortran version 8.1.0
Here is the link to the files
https://1drv.ms/f/s!AjG0dE43DVddaJfY62ABE8Yq3CI

Answer 1

When you need to add a call to a subroutine that shouldn't actually change anything in order to get things working, you probably have a memory corruption. This happens most often when you access arrays outside of their boundaries.
I have compiled it with some run time checks:
gfortran -o p2m -g -O0 -fbacktrace -fcheck=all -Wall proj2mat.f90
And it's already giving me some issues:
It's warning me about implicit type conversions. That shouldn't be too much of an issue if you trust your data.
In line 46 you have an array length mismatch (x0(:, 1) has length 40, q(:,1) is 41)
Similarly on line 108 (x=b) x is really large, but b is only 41 long.
I have stopped now, but I implore you to go through your code and clean it up. Use the compiler options above which will let you know when and where there is an array bound violation.