Question about MPI_SEND and MPI_RECV command - fortran

Question

I modified my code and put MPI_RECV before MPI_SEND. This time, I did not receive any error message; however, it seemed that code still encountered deadlock. The reason is that I opened some files (UNIT=11, 12, 13,14) before MPI_RECV and MPI_SEND commands; then, I collected data through these two commands and wrote them into these files but there was no data written into these files. I paste my modified code below. Would you please have a look at it and give me some suggestions? Thank you so much.
PROGRAM MAIN
USE MPI
USE CAL
IMPLICIT NONE
INTEGER :: nb !Number of valence band
DOUBLE PRECISION :: me !Minimum eigen value
DOUBLE COMPLEX, ALLOCATABLE :: u_s1(:,:) !Array to store the contribution of each eigen state to the total spin orbit torque
DOUBLE COMPLEX, ALLOCATABLE :: u_s2(:,:) !Array to store the contribution of each eigen state to the total spin orbit torque
DOUBLE COMPLEX, ALLOCATABLE :: u_t1(:,:) !Array to collect the contribution of each eigen state to the total spin orbit torque from all processors
DOUBLE COMPLEX, ALLOCATABLE :: u_t2(:,:) !Array to collect the contribution of each eigen state to the total spin orbit torque from all processors
DOUBLE COMPLEX :: sr1 !Sum of Femri surface part for spin orbit torque on all km(1) k points
DOUBLE COMPLEX :: sr2 !Sum of Femri surface part for spin orbit torque on all km(1) k points
DOUBLE PRECISION, ALLOCATABLE, TARGET :: nme(:) !Array to store the minimum eigen value
INTEGER, ALLOCATABLE, TARGET :: nnb(:) !Array to store the number of valence band
INTEGER :: world_size !MPI
INTEGER :: world_rank, ierr !MPI
INTEGER :: irank, j0 !MPI
!
!Initializing MPI
CALL MPI_Init(ierr)
CALL MPI_Comm_size(MPI_COMM_WORLD, world_size, ierr)
CALL MPI_Comm_rank(MPI_COMM_WORLD, world_rank, ierr)
!
!Opening file that stores the total spin orbit torque value for the Fermi surface part
OPEN (UNIT=11, FILE='SOT_Surface.dat', STATUS='UNKNOWN')
!
!Opening file that stores the spin orbit torque for the Fermi surface part versus energy
OPEN (UNIT=12, FILE='SOT_Surface_sve_xz.dat', STATUS='UNKNOWN')
OPEN (UNIT=13, FILE='SOT_Surface_sve_yz.dat', STATUS='UNKNOWN')
!
!Opening file that stores the minimum eigen value and number of valence band
OPEN (UNIT=14, FILE='SOT_mineig_numval.dat', STATUS='UNKNOWN')
!
!Allocating the array used to store the contribution of each eigen state to the total spin orbit torque
ALLOCATE (u_s1(2,nu_wa*km(1)))
ALLOCATE (u_s2(2,nu_wa*km(1)))
!
!Allocating array to collect the contribution of each eigen state to the total spin orbit torque from all processors
IF (world_rank .EQ. 0) THEN
ALLOCATE (u_t1(2,nu_wa*km(1)*km(2)))
ALLOCATE (u_t2(2,nu_wa*km(1)*km(2)))
END IF
u_t1 = CMPLX(0.0d0, 0.0d0)
u_t2 = CMPLX(0.0d0, 0.0d0)
!
!Allocating array to collect the number of valence band and the minimum eigen value
IF (world_rank .EQ. 0) THEN
ALLOCATE (nme(km(2)))
ALLOCATE (nnb(km(2)))
END IF
nme = 0.0d0
nnb = 0
!
!Allocating array to collect the contribution of each eigen state to the total spin orbit torque from all processors
IF (world_rank .EQ. 0) THEN
ALLOCATE (u_t1(2,nu_wa*km(1)*km(2)))
ALLOCATE (u_t2(2,nu_wa*km(1)*km(2)))
END IF
u_t1 = CMPLX(0.0d0, 0.0d0)
u_t2 = CMPLX(0.0d0, 0.0d0)
!
!Allocating array to collect the number of valence band and the minimum eigen value
IF (world_rank .EQ. 0) THEN
ALLOCATE (nme(km(2)))
ALLOCATE (nnb(km(2)))
END IF
nme = 0.0d0
nnb = 0
!
!opening test files
open (unit=21,file='normalisedprefactor.dat',status='unknown')
open (unit=22,file='gd.dat',status='unknown')
open (unit=23,file='con.dat',status='unknown')
open (unit=24,file='par.dat',status='unknown')
open (unit=25,file='grga.dat',status='unknown')
open (unit=26,file='nfdk.dat',status='unknown')
!Reading the Cartesian coordinates of k-point mesh
DO j = 1, km(2), 1
IF (mod(j-1, world_size) .NE. world_rank) CYCLE
DO k = 1, km(1), 1
kp(k,:) = ka(j,k,:)
END DO
!Building up Hamiltonian matrix on k points and diagonalising the matrix to obtain Eigen vectors and values
CALL HAMSUR(vd,kp,nu_wa,nu_nr,km(1),nd1,nd2,nd3,nd4,nd5,hr1,hr2,hr3,hr4,hr5,tb,ec,ev,fermi,an,wf,bv,dk,u_s1,u_s2,sr1,sr2,nb,me)
!
CALL MPI_Barrier(MPI_COMM_WORLD, ierr)
IF (WORLD_RANK .EQ. 0) THEN
u_t1(1:2,1+nu_wa*km(1)*(j-1):nu_wa*km(1)*j) = u_s1
u_t2(1:2,1+nu_wa*km(1)*(j-1):nu_wa*km(1)*j) = u_s2
DO k = 1, WORLD_SIZE-1, 1
IF (j-1+k .EQ. km(2)) EXIT
l = k + 101
n = k + 102
CALL MPI_RECV(u_t1(1,1+nu_wa*km(1)*(j-1+k)), 2*nu_wa*km(1), MPI_DOUBLE_COMPLEX, k,l, MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
CALL MPI_RECV(u_t2(1,1+nu_wa*km(1)*(j-1+k)), 2*nu_wa*km(1), MPI_DOUBLE_COMPLEX, k,n, MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
END DO
ELSE
l = WORLD_RANK + 101
n = WORLD_RANK + 102
CALL MPI_SEND(u_s1,2*nu_wa*km(1), MPI_DOUBLE_COMPLEX, 0, l, MPI_COMM_WORLD, ierr)
CALL MPI_SEND(u_s2,2*nu_wa*km(1), MPI_DOUBLE_COMPLEX, 0, n, MPI_COMM_WORLD, ierr)
END IF
crr1 = crr1 + sr1
crr2 = crr2 + sr2
IF (WORLD_RANK .EQ. 0) THEN
nme(j-1) = me
nnb(j-1) = nb
DO k = 1, WORLD_SIZE-1, 1
IF (j-1+k .EQ. km(2)) EXIT
l = k + 103
n = k + 104
CALL MPI_RECV(nme(j-1+k), 1, MPI_DOUBLE, k,l, MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
CALL MPI_RECV(nnb(j-1+k), 1, MPI_INT, k,n, MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
END DO
ELSE
l = WORLD_RANK + 103
n = WORLD_RANK + 104
CALL MPI_SEND(me, 1, MPI_DOUBLE, 0, l, MPI_COMM_WORLD, ierr)
CALL MPI_SEND(nb, 1, MPI_INT, 0, n, MPI_COMM_WORLD, ierr)
END IF
END DO
!
CALL MPI_Barrier(MPI_COMM_WORLD, ierr)
IF (world_rank .EQ. 0) THEN
ALLOCATE (crr1_all(world_size))
ALLOCATE (crr2_all(world_size))
END IF
crr1_all = CMPLX(0.0d0, 0.0d0)
crr2_all = CMPLX(0.0d0, 0.0d0)
CALL MPI_Gather(crr1, 1, MPI_double_complex, crr1_all, 1, MPI_double_complex, 0, MPI_COMM_WORLD, ierr)
CALL MPI_Gather(crr2, 1, MPI_double_complex, crr2_all, 1, MPI_double_complex, 0, MPI_COMM_WORLD, ierr)
!Writing total conductivity value into the file
IF (world_rank .EQ. 0) THEN
crr1_total = CMPLX(0.0d0, 0.0d0)
crr2_total = CMPLX(0.0d0, 0.0d0)
DO i = 1, world_size, 1
crr1_total = crr1_total + crr1_all(i)
crr2_total = crr2_total + crr2_all(i)
END DO
!Finding the minimum eigen value
NULLIFY (p1, p2)
p1 => nme(1)
p2 => nnb(1)
DO i = 2, km(2), 1
IF (p1 .GE. nme(i)) THEN
p1 => nme(i)
END IF
IF (p2 .LE. nnb(i)) THEN
p2 => nnb(i)
END IF
END DO
WRITE (UNIT=14, FMT='(A27,$)') 'The minimum eigen value is:'
WRITE (UNIT=14, FMT=*) p1
WRITE (UNIT=14, FMT='(A30,$)') 'The number of valence band is:'
WRITE (UNIT=14, FMT=*) p2
!
!Constant for the coefficient
pi = DACOS(-1.0d0)
hb = 1.054571817d-34 !(unit - J)
es = 1.602176634d-19 !(unit - J*s)
!
WRITE (UNIT=11, FMT='(A55,$)') 'Spin Orbit Torque without coeffieicnt within x-z plane:'
WRITE (UNIT=11, FMT=*) crr1_total
WRITE (UNIT=11, FMT='(A52,$)') 'Spin Orbit Torque with coefficient within x-z plane:'
WRITE (UNIT=11, FMT=*) crr1_total * es ** 2 * hb / 4.0d0 / pi
WRITE (UNIT=11, FMT='(A55,$)') 'Spin Orbit Torque without coeffieicnt within y-z plane:'
WRITE (UNIT=11, FMT=*) crr2_total
WRITE (UNIT=11, FMT='(A52,$)') 'Spin Orbit Torque with coefficient within y-z plane:'
WRITE (UNIT=11, FMT=*) crr2_total * es ** 2 * hb / 4.0d0 / pi
DO i = 1, nu_wa*km(1)*km(2), 1
WRITE (UNIT=12, FMT=*) u_t1(1:2,i)
WRITE (UNIT=13, FMT=*) u_t2(1:2,i)
END DO
END IF
!
!Finalising MPI
CALL MPI_Finalize(ierr)
!
!Deallocating array that sotres and collect the fermi-surface-part contribution of each eigen state to the total spin orbit torque
DEALLOCATE (u_s1)
DEALLOCATE (u_s2)
DEALLOCATE (u_t1)
DEALLOCATE (u_t2)
!
STOP
END PROGRAM MAIN