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## stack overflow caused by !DIR\$ SIMD LASTPRIVATE REDUCTION

Beginner
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I analyzed my code with Intel Advisor 2019. Then, I decided to try the vectorize the most consuming CPU loop of my code. Hence, I compiled it with /Qopt-report:5 option as guide to vectorize the loop. Finally, I was able to vectorize with the next directive

```m=0.0

! form banded matrix of Puasson equastion
pok=3.
call annotate_site_begin( "pressure" )
call annotate_iteration_task( "pressure-task" )
do 99 k=2,kbm1
! REVERTED Change the order of the do, so they can fit the model of array in fortran

do 99 j=2,jmm1
!DIR\$ SIMD LASTPRIVATE(bb2) REDUCTION(+:m, gc2, gc1, gen)
do 99 i=2,imm1

if (k+1<=kb.and.i+1<=im)then
aa1(i+1,j,k+1)=.25e0*aaf(i+1,j,k+1)
1 *.5*(dy(i,j)+dy(i+1,j))/ddx(i,j)/art(i,j)
1 +.25e0*aaf(i,j,k+1)*dq(i+1,j)/dq(i,j)
1 *dy(i,j)/ddx(i,j)/art(i,j)
endif
if (k+1<=kb.and.i-1>=1)then
aa2(i-1,j,k+1)=-.25e0*aaf(i-1,j,k+1)
1 *.5*(dy(i,j)+dy(i-1,j))/ddx(i-1,j)/art(i,j)
1 -.25e0*aaf(i,j,k+1)*dq(i-1,j)/dq(i,j)
1 *dy(i,j)/ddx(i,j)/art(i,j)
end if
if (k-1>=1.and.i+1<=im)then
aa3(i+1,j,k-1)=-.25e0*aaf(i+1,j,k-1)
1 *.5*(dy(i,j)+dy(i+1,j))/ddx(i,j)/art(i,j)
1 -.25e0*aaf(i,j,k-1)*dq(i+1,j)/dq(i,j)
1 *dy(i,j)/ddx(i,j)/art(i,j)
end if
if (k-1>=1.and.i-1>=1)then
aa4(i-1,j,k-1)=.25e0*aaf(i-1,j,k-1)
1 *.5*(dy(i,j)+dy(i-1,j))/ddx(i-1,j)/art(i,j)
1 +.25e0*aaf(i,j,k-1)*dq(i-1,j)/dq(i,j)
1 *dy(i,j)/ddx(i,j)/art(i,j)
end if
if (k+1<=kb.and.j+1<=jm)then
bb1(i,j+1,k+1)=.25e0*bbf(i,j+1,k+1)
1 *.5*(dx(i,j)+dx(i,j+1))/ddy(i,j)/art(i,j)
1 +.25e0*bbf(i,j,k+1)*dq(i,j+1)/dq(i,j)
1 *dx(i,j)/ddy(i,j)/art(i,j)
end if
if (k+1<=kb.and.j-1>=1)then
bb2(i,j-1,k+1)=-.25e0*bbf(i,j-1,k+1)
1 *.5*(dx(i,j)+dx(i,j-1))/ddy(i,j-1)/art(i,j)
1 -.25e0*bbf(i,j,k+1)*dq(i,j-1)/dq(i,j)
1 *dx(i,j)/ddy(i,j)/art(i,j)
end if
if (k-1>=1.and.j+1<=jm)then
bb3(i,j+1,k-1)=-.25e0*bbf(i,j+1,k-1)
1 *.5*(dx(i,j)+dx(i,j+1))/ddy(i,j)/art(i,j)
1 -.25e0*bbf(i,j,k-1)*dq(i,j+1)/dq(i,j)
1 *dx(i,j)/ddy(i,j)/art(i,j)
end if
if (k-1>=1.and.j-1>=1) then
bb4(i,j-1,k-1)=.25e0*bbf(i,j-1,k-1)
1 *.5*(dx(i,j)+dx(i,j-1))/ddx(i,j-1)/art(i,j)
1 +.25e0*bbf(i,j,k-1)*dq(i,j-1)/dq(i,j)
1 *dx(i,j)/ddy(i,j)/art(i,j)
end if
if (i+1<=im) then
ga1(i+1,j,k)=dz(k)*dq(i+1,j)
1 *.5*(dy(i,j)+dy(i+1,j))/ddx(i,j)/art(i,j)
end if
if (i-1>=1) then
ga2(i-1,j,k)=dz(k)*dq(i-1,j)
1 *.5*(dy(i,j)+dy(i-1,j))/ddx(i-1,j)/art(i,j)
end if
if (j+1<=jm) then
gb1(i,j+1,k)=dz(k)*dq(i,j+1)
1 *.5*(dx(i,j)+dx(i,j+1))/ddy(i,j)/art(i,j)
end if
if (j-1>=1) then
gb2(i,j-1,k)=dz(k)*dq(i,j-1)
1 *.5*(dx(i,j)+dx(i,j-1))/ddy(i,j-1)/art(i,j)
end if
if (k+1<=kb) then
gc1(i,j,k+1)=1.e0/(dzz(k)*dq(i,j))*
1 (art(i,j)+.5*(aaf(i,j,k+1)+aaf(i,j,k))*aaf(i,j,k+1)*dy(i,j)/
1 dx(i,j)+.5*(bbf(i,j,k+1)+bbf(i,j,k))*bbf(i,j,k+1)*dx(i,j)/
1 dy(i,j))/art(i,j)
end if
if (k-1>=1) then
gc2(i,j,k-1)=1.e0/(dzz(k-1)*dq(i,j))*
1 (art(i,j)+.5*(aaf(i,j,k-1)+aaf(i,j,k))*aaf(i,j,k-1)*dy(i,j)/
1 dx(i,j)+.5*(bbf(i,j,k-1)+bbf(i,j,k))*bbf(i,j,k-1)*dx(i,j)/
1 dy(i,j))/art(i,j)
end if
!	if(iint==5)stop
if (i-1>=1.and.j-1>=1.and.k-1>=1.) then
gen(i,j,k)=(-dq(i,j)*dz(k)*(.5*(dy(i,j)+dy(i+1,j))/ddx(i,j)+
1 .5*(dy(i,j)+dy(i-1,j))/ddx(i-1,j)+
1 .5*(dx(i,j)+dx(i,j+1))/ddy(i,j)+
1 .5*(dx(i,j)+dx(i,j-1))/ddy(i,j-1)))/art(i,j)-
2 (1.e0/dzz(k-1)+1.e0/dzz(k))/dq(i,j)*(art(i,j)
1 +.5*(aaf(i,j,k+1)+aaf(i,j,k))*aaf(i,j,k)*dy(i,j)/dx(i,j)+
1 .5*(bbf(i,j,k+1)+bbf(i,j,k))*bbf(i,j,k)*dx(i,j)/dy(i,j)
1 )/art(i,j)
else
gen(i,j,k)=(-dq(i,j)*dz(k)*(dy(i,j)/ddx(i,j)+
1 dy(i,j)/ddx(i-1,j)+
1 dx(i,j)/ddy(i,j)+
1 dx(i,j)/ddy(i,j-1)))/art(i,j)-
2 (2.e0/dzz(k))/dq(i,j)*
1 (art(i,j)+.5*(aaf(i,j,k+1)+aaf(i,j,k))*aaf(i,j,k)*dy(i,j)/dx(i,j)+
1 .5*(bbf(i,j,k+1)+bbf(i,j,k))*bbf(i,j,k)*dx(i,j)/dy(i,j)
1 )/art(i,j)
end if

if (((k-1)*(k-kb)*(i-1)*(i-im)*(j-1)*(j-jm)).ne.0) then
m=m+1

if (k==kbm1) then
ga1(i+1,j,k)=ga1(i+1,j,k)+aa1(i+1,j,k+1)
ga2(i-1,j,k)=ga2(i-1,j,k)+aa2(i-1,j,k+1)
gb1(i,j+1,k)=gb1(i,j+1,k)+bb1(i,j+1,k+1)
gb2(i,j-1,k)=gb2(i,j-1,k)+bb2(i,j-1,k+1)
gen(i,j,k)=gen(i,j,k)+gc1(i,j,k+1)
endif

if (k==2) then !¸òþñþôýð  ÿþòõ¨¿ýþ¸ª¹
aa2(i+1,j,k-1)=0.
bb2(i,j+1,k-1)=0.
bb4(i,j-1,k-1)=0.
gc2(i,j,k-1)=0.
endif

if (i==2) then
gc2(i,j,k-1)=gc2(i,j,k-1)+aa4(i-1,j,k-1)
gc1(i,j,k+1)=gc1(i,j,k+1)+aa2(i-1,j,k+1)
gen(i,j,k)=gen(i,j,k)+ga2(i-1,j,k)
endif

if (i==imm1) then
gc2(i,j,k-1)=gc2(i,j,k-1)+aa3(i+1,j,k-1)
gc1(i,j,k+1)=gc1(i,j,k+1)+aa1(i+1,j,k+1)
gen(i,j,k)=gen(i,j,k)+ga1(i+1,j,k)
endif

if (j==2) then
gc2(i,j,k-1)=gc2(i,j,k-1)+bb4(i,j-1,k-1)
gc1(i,j,k+1)=gc1(i,j,k+1)+bb2(i,j-1,k+1)
gen(i,j,k)=gen(i,j,k)+gb2(i,j-1,k)
endif

if (j==jmm1) then
gc2(i,j,k-1)=gc2(i,j,k-1)+bb3(i,j+1,k-1)
gc1(i,j,k+1)=gc1(i,j,k+1)+bb1(i,j+1,k+1)
gen(i,j,k)=gen(i,j,k)+gb1(i,j+1,k)
endif
endif

if (maa1+m<=lm) then
if (k+1>kbm1.or.i+1>imm1) then
apr(m)=0.0
else
apr(m)=aa1(i+1,j,k+1)
end if
ja(m)=ind(m+maa1)
ia(m)=ind(m)
end if
lapr=ma1
if (mbb1+m<=lm) then
if (k+1>kbm1.or.j+1>jmm1) then
apr(lapr+m)=0.0
else
apr(lapr+m)=bb1(i,j+1,k+1)
end if
ja(m+lapr)=ind(m+mbb1)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1
if (mgc+m<=lm) then
if (k+1>kbm1) then
apr(lapr+m)=0.0
else
apr(lapr+m)=gc1(i,j,k+1)
end if
ja(m+lapr)=ind(m+mgc)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1+mc
if (mbb2+m<=lm) then
if (k+1>kbm1.or.j-1<2) then
apr(lapr+m)=0.0
else
apr(lapr+m)=bb2(i,j-1,k+1)
end if
ja(m+lapr)=ind(m+mbb2)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1+mc+mb2
if (maa2+m<=lm) then
if (k+1>kbm1.or.i-1<2) then
apr(lapr+m)=0.0
else
apr(lapr+m)=aa2(i-1,j,k+1)
endif
ja(m+lapr)=ind(m+maa2)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1+mc+mb2+ma2
if (mga+m<=lm) then
if (i+1>imm1) then
apr(lapr+m)=0.0
else
apr(lapr+m)=ga1(i+1,j,k)
end if
ja(m+lapr)=ind(m+mga)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1+mc+mb2+ma2+ma
if (1+m<=lm) then
if (j+1>jmm1) then
apr(lapr+m)=0.0
else
apr(lapr+m)=gb1(i,j+1,k)
end if
ja(m+lapr)=ind(m+mgb)
ia(m+lapr)=ind(m)
end if
lapr=ma1+mb1+mc+mb2+ma2+ma+mb
apr(lapr+m)=gen(i,j,k)
ja(m+lapr)=ind(m)
ia(m+lapr)=ind(m)
lapr=ma1+mb1+mc+mb2+ma2+ma+mb+lm
if (m-mgb>=1) then
if (j-1<2) then
apr(m-mgb+lapr)=0.0
else
apr(m-mgb+lapr)=gb2(i,j-1,k)
end if
ja(m-mgb+lapr)=ind(m-mgb)
ia(m-mgb+lapr)=ind(m)
end if
lapr=ma1+mb1+mc+mb2+ma2+ma+2*mb+lm
if (m-mga>=1) then
if (i-1<2) then
apr(m-mga+lapr)=0.0
else
apr(m-mga+lapr)=ga2(i-1,j,k)
end if
ia(m-mga+lapr)=ind(m)
ja(m-mga+lapr)=ind(-mga+m)
end if
lapr=ma1+mb1+mc+mb2+ma2+2*ma+2*mb+lm
if (m-maa2>=1) then
if (k-1<2.or.i+1>imm1) then
apr(m-maa2+lapr)=0.0
else
apr(m-maa2+lapr)=aa3(i+1,j,k-1)
endif
ia(m-maa2+lapr)=ind(m)
ja(m-maa2+lapr)=ind(-maa2+m)
end if
lapr=ma1+mb1+mc+mb2+2*ma2+2*ma+2*mb+lm
if (m-mbb2>=1) then
if (j+1>jmm1.or.k-1<2) then
apr(m-mbb2+lapr)=0.0
else
apr(m-mbb2+lapr)=bb3(i,j+1,k-1)
endif
ia(m-mbb2+lapr)=ind(m)
ja(m-mbb2+lapr)=ind(-mbb2+m)
end if
lapr=ma1+mb1+mc+2*mb2+2*ma2+2*ma+2*mb+lm
if(m-mgc>=1)then
if (k-1>kbm1) then
apr(m-mgc+lapr)=0.0
else
apr(m-mgc+lapr)=gc2(i,j,k-1)
end if
ja(m-mgc+lapr)=ind(m-mgc)
ia(m-mgc+lapr)=ind(m)
end if
lapr=ma1+mb1+2*mc+2*mb2+2*ma2+2*ma+2*mb+lm
if (m-mbb1>=1) then
if (j-1<2.or.k-1<2)then
apr(m-mbb1+lapr)=0.0
else
apr(m-mbb1+lapr)=bb4(i,j-1,k-1)
endif
ia(m-mbb1+lapr)=ind(m)
ja(m-mbb1+lapr)=ind(m-mbb1)
end if
lapr=ma1+2*mb1+2*mc+2*mb2+2*ma2+2*ma+2*mb+lm
if (m-maa1>=1) then
if (i-1<2.or.k-1<2)then
apr(m-maa1+lapr)=0.0
else
apr(m-maa1+lapr)=aa4(i-1,j,k-1)
endif
ia(m-maa1+lapr)=ind(m)
ja(m-maa1+lapr)=ind(m-maa1)
end if

99	continue
call annotate_site_end```

However, when I run my code I'm getting a stack overflow exception

```forrtl: severe (170): Program Exception - stack overflow
Image              PC                Routine         Line     Source
nohydroPOM.exe     00007FF7B4D83E38  Unknown         Unknown  Unknown
nohydroPOM.exe     00007FF7B4D64484  PRESSURE1            1   pressure1.for
nohydroPOM.exe     00007FF7B4D4EABB  MAIN__             620  Main.for
nohydroPOM.exe     00007FF7B4D83C02  Unknown        Unknown  Unknown
nohydroPOM.exe     00007FF7B4D8406D  Unknown        Unknown  Unknown
KERNEL32.DLL       00007FFD4FE14034  Unknown        Unknown  Unknown
ntdll.dll          00007FFD500F3691  Unknown        Unknown  Unknown
```

I noticed some messages like this

pressure1.for(273,7):remark #15329: vectorization support: irregularly indexed store was emulated for the variable <APR(M)>, masked, part of index is linear but may overflow

I have looking for more information about this message and how to fix it, but I haven't had any success so far. I have been looking for ways to troubleshoot stack overflow issues and tried some solutions -like increasing the size of stack, using heaparrays option, etc- but I'm still getting the same error. I will include the whole solution files in this post. I'm open to any suggestion about how to vectorize this loop. I will appreciate if someone provide more information about diagnostic message 15329 too.

My environment is

Windows 10 Home Version 10.0.17134 Build 17134

Visual Studio Community 2015 Version 14.0.25431.01 Update 3

Intel Parallel Studio XE 2019 Update 3 Cluster Edition for Windows

Regards,

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