added parallel double precision spspmm implementations

base/modules/Makefile

@@ -64,7 +64,8 @@ SERIAL_MODS=serial/psb_s_serial_mod.o serial/psb_d_serial_mod.o \
 	serial/psb_s_base_mat_mod.o serial/psb_s_csr_mat_mod.o serial/psb_s_csc_mat_mod.o serial/psb_s_mat_mod.o \
 	serial/psb_d_base_mat_mod.o serial/psb_d_csr_mat_mod.o serial/psb_d_csc_mat_mod.o serial/psb_d_mat_mod.o \
 	serial/psb_c_base_mat_mod.o serial/psb_c_csr_mat_mod.o serial/psb_c_csc_mat_mod.o serial/psb_c_mat_mod.o \
-	serial/psb_z_base_mat_mod.o serial/psb_z_csr_mat_mod.o serial/psb_z_csc_mat_mod.o serial/psb_z_mat_mod.o
+	serial/psb_z_base_mat_mod.o serial/psb_z_csr_mat_mod.o serial/psb_z_csc_mat_mod.o serial/psb_z_mat_mod.o \
+	serial/psb_d_rb_idx_tree_mod.o serial/psb_rb_idx_tree_mod.o
 #\
 #	serial/psb_ls_csr_mat_mod.o serial/psb_ld_csr_mat_mod.o serial/psb_lc_csr_mat_mod.o serial/psb_lz_csr_mat_mod.o 
 #\
@@ -270,6 +271,9 @@ serial/psb_z_vect_mod.o: serial/psb_z_base_vect_mod.o serial/psb_i_vect_mod.o
 serial/psb_s_serial_mod.o serial/psb_d_serial_mod.o serial/psb_c_serial_mod.o serial/psb_z_serial_mod.o: serial/psb_mat_mod.o auxil/psb_string_mod.o auxil/psb_sort_mod.o auxil/psi_serial_mod.o
 serial/psb_vect_mod.o: serial/psb_i_vect_mod.o serial/psb_l_vect_mod.o serial/psb_d_vect_mod.o serial/psb_s_vect_mod.o serial/psb_c_vect_mod.o serial/psb_z_vect_mod.o
 
+serial/psb_d_rb_idx_tree_mod.o: serial/psb_d_csr_mat_mod.o
+serial/psb_rb_idx_tree_mod.o: serial/psb_d_rb_idx_tree_mod.o
+
 error.o psb_realloc_mod.o: psb_error_mod.o 
 psb_error_impl.o: psb_penv_mod.o
 psb_timers_mod.o: psb_penv_mod.o psb_const_mod.o psb_realloc_mod.o psb_error_mod.o

base/modules/serial/psb_d_csr_mat_mod.f90

@@ -46,6 +46,14 @@ module psb_d_csr_mat_mod
 
   use psb_d_base_mat_mod
 
+  integer(psb_ipk_), parameter :: spspmm_serial = 0
+  integer(psb_ipk_), parameter :: spspmm_omp_gustavson = 1
+  integer(psb_ipk_), parameter :: spspmm_omp_gustavson_1d = 2
+  integer(psb_ipk_), parameter :: spspmm_serial_rb_tree = 3
+  integer(psb_ipk_), parameter :: spspmm_omp_rb_tree = 4
+  integer(psb_ipk_), parameter :: spspmm_omp_two_pass = 5
+  integer(psb_ipk_) :: spspmm_impl = spspmm_serial
+
   !> \namespace  psb_base_mod  \class  psb_d_csr_sparse_mat
   !! \extends psb_d_base_mat_mod::psb_d_base_sparse_mat
   !!

base/modules/serial/psb_d_mat_mod.F90

@@ -79,7 +79,10 @@
 module psb_d_mat_mod
 
   use psb_d_base_mat_mod
-  use psb_d_csr_mat_mod,  only : psb_d_csr_sparse_mat, psb_ld_csr_sparse_mat
+  use psb_d_csr_mat_mod,  only : psb_d_csr_sparse_mat, psb_ld_csr_sparse_mat, &
+                                spspmm_impl, spspmm_serial, spspmm_omp_gustavson, &
+                                spspmm_omp_gustavson_1d, spspmm_serial_rb_tree, &
+                                spspmm_omp_rb_tree, spspmm_omp_two_pass
   use psb_d_csc_mat_mod,  only : psb_d_csc_sparse_mat, psb_ld_csc_sparse_mat
 
   type :: psb_dspmat_type

base/modules/serial/psb_d_rb_idx_tree_mod.f90

@@ -0,0 +1,91 @@
+! Red black tree implementation ordered by index
+!
+! Each node contains and index and a double precision value
+!
+! The tree should always be well balanced
+!
+! inserting a node with an existing index will 
+! add up the new value to the old one
+module psb_d_rb_idx_tree_mod
+    use psb_const_mod
+    implicit none
+    type :: psb_d_rb_idx_node
+        integer(psb_ipk_) :: idx
+        real(psb_dpk_) :: val
+        type(psb_d_rb_idx_node), pointer :: left, right, parent
+        logical :: is_red
+    end type psb_d_rb_idx_node
+
+    type :: psb_d_rb_idx_tree
+        type(psb_d_rb_idx_node), pointer :: root
+        integer(psb_ipk_) :: nnz
+
+        contains
+
+        procedure :: insert => psb_d_rb_idx_tree_insert
+    end type psb_d_rb_idx_tree
+
+    interface psb_rb_idx_tree_insert
+    subroutine psb_d_rb_idx_tree_insert(this, idx, val)
+        import :: psb_ipk_, psb_dpk_, psb_d_rb_idx_tree
+        implicit none
+        class(psb_d_rb_idx_tree), intent(inout) :: this
+        integer(psb_ipk_), intent(in) :: idx
+        real(psb_dpk_), intent(in) :: val
+    end subroutine psb_d_rb_idx_tree_insert
+    end interface psb_rb_idx_tree_insert
+    
+    interface psb_rb_idx_tree_scalar_sparse_row_mul
+    subroutine psb_d_rb_idx_tree_scalar_sparse_row_mul(tree, scalar, mat, row_num)
+        use psb_d_csr_mat_mod, only : psb_d_csr_sparse_mat
+        import :: psb_ipk_, psb_dpk_, psb_d_rb_idx_tree
+        implicit none
+        type(psb_d_rb_idx_tree), intent(inout) :: tree
+        real(psb_dpk_), intent(in) :: scalar
+        type(psb_d_csr_sparse_mat), intent(in) :: mat
+        integer(psb_ipk_), intent(in) :: row_num
+    end subroutine psb_d_rb_idx_tree_scalar_sparse_row_mul
+    end interface psb_rb_idx_tree_scalar_sparse_row_mul
+ 
+    interface psb_rb_idx_tree_merge
+    subroutine psb_d_rb_idx_tree_merge(trees, mat)
+        use psb_d_csr_mat_mod, only : psb_d_csr_sparse_mat
+        import :: psb_d_rb_idx_tree
+        type(psb_d_rb_idx_tree), allocatable, intent(inout) :: trees(:)
+        type(psb_d_csr_sparse_mat), intent(inout) :: mat
+    end subroutine psb_d_rb_idx_tree_merge
+    end interface psb_rb_idx_tree_merge
+    
+    interface psb_rb_idx_tree_fix_insertion
+    subroutine psb_d_rb_idx_tree_fix_insertion(this, node)
+        import :: psb_d_rb_idx_tree, psb_d_rb_idx_node
+        implicit none
+        class(psb_d_rb_idx_tree), intent(inout) :: this
+        type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+    end subroutine psb_d_rb_idx_tree_fix_insertion
+    end interface psb_rb_idx_tree_fix_insertion
+
+    interface psb_rb_idx_tree_swap_colors
+    subroutine psb_d_rb_idx_tree_swap_colors(n1, n2)
+        import :: psb_d_rb_idx_node
+        implicit none
+        type(psb_d_rb_idx_node), pointer, intent(inout) :: n1, n2
+    end subroutine psb_d_rb_idx_tree_swap_colors
+    end interface psb_rb_idx_tree_swap_colors
+
+    interface psb_rb_idx_tree_rotate_right
+    subroutine psb_d_rb_idx_tree_rotate_right(node)
+        import :: psb_d_rb_idx_node
+        implicit none
+        type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+    end subroutine psb_d_rb_idx_tree_rotate_right
+    end interface psb_rb_idx_tree_rotate_right
+
+    interface psb_rb_idx_tree_rotate_left
+    subroutine psb_d_rb_idx_tree_rotate_left(node)
+        import :: psb_d_rb_idx_node
+        implicit none
+        type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+    end subroutine psb_d_rb_idx_tree_rotate_left
+    end interface psb_rb_idx_tree_rotate_left
+end module psb_d_rb_idx_tree_mod

base/modules/serial/psb_rb_idx_tree_mod.f90

@@ -0,0 +1,5 @@
+module psb_rb_idx_tree_mod
+    use psb_const_mod
+
+    use psb_d_rb_idx_tree_mod
+end module psb_rb_idx_tree_mod

base/serial/impl/Makefile

@@ -10,7 +10,7 @@ BOBJS=psb_base_mat_impl.o \
 SOBJS=psb_s_csr_impl.o psb_s_coo_impl.o psb_s_csc_impl.o psb_s_mat_impl.o
 #\
  psb_s_lcoo_impl.o psb_s_lcsr_impl.o 
-DOBJS=psb_d_csr_impl.o psb_d_coo_impl.o psb_d_csc_impl.o psb_d_mat_impl.o
+DOBJS=psb_d_csr_impl.o psb_d_coo_impl.o psb_d_csc_impl.o psb_d_mat_impl.o psb_d_rb_idx_tree_impl.o
 #\
  psb_d_lcoo_impl.o  psb_d_lcsr_impl.o 
 COBJS=psb_c_csr_impl.o psb_c_coo_impl.o psb_c_csc_impl.o psb_c_mat_impl.o

base/serial/impl/psb_d_csr_impl.F90

@@ -3349,13 +3349,30 @@ subroutine psb_dcsrspspmm(a,b,c,info)
     goto 9999
   endif
 
-  ! Estimate number of nonzeros on output.
+  select case(spspmm_impl)
-  nza = a%get_nzeros()
+  case (spspmm_serial)
-  nzb = b%get_nzeros()
+    ! Estimate number of nonzeros on output.
-  nzc = 2*(nza+nzb)
+    nza = a%get_nzeros()
-  call c%allocate(ma,nb,nzc)
+    nzb = b%get_nzeros()
-
+    nzc = 2*(nza+nzb)
-  call csr_spspmm(a,b,c,info)
+    call c%allocate(ma,nb,nzc)
+
+    call csr_spspmm(a,b,c,info)
+  case (spspmm_omp_gustavson)
+    call spmm_omp_gustavson(a,b,c,info)
+  case (spspmm_omp_gustavson_1d)
+    call spmm_omp_gustavson_1d(a,b,c,info)
+  case (spspmm_serial_rb_tree)
+    call spmm_serial_rb_tree(a,b,c,info)
+  case (spspmm_omp_rb_tree)
+    call spmm_omp_rb_tree(a,b,c,info)
+  case (spspmm_omp_two_pass)
+    call spmm_omp_two_pass(a,b,c,info)
+  case default
+    write(psb_err_unit,*) 'Unknown spspmm implementation'
+    ! push error
+    goto 9999
+  end select
 
   call c%set_asb()
   call c%set_host()
@@ -3434,9 +3451,400 @@ contains
     end do
 
     c%irp(ma+1) = nzc
+  end subroutine csr_spspmm
 
+  ! gustavson's algorithm using perfect hashing 
+    ! and OpenMP parallelisation
+  subroutine spmm_omp_gustavson(a,b,c,info)
+    use omp_lib
 
-  end subroutine csr_spspmm
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+    
+    real(psb_dpk_), allocatable :: vals(:), acc(:)
+    integer(psb_ipk_)   :: ma, nb
+    integer(psb_ipk_), allocatable :: col_inds(:), offsets(:)
+    integer(psb_ipk_)   :: irw, jj, j, k, nnz, rwnz, thread_upperbound, start_idx, end_idx
+    
+    ma = a%get_nrows()
+    nb = b%get_ncols()
+
+    call c%allocate(ma, nb)
+    c%irp(1) = 1
+
+    ! dense accumulator
+    ! https://sc18.supercomputing.org/proceedings/workshops/workshop_files/ws_lasalss115s2-file1.pdf
+    call psb_realloc(nb, acc, info)
+    
+    allocate(offsets(omp_get_max_threads()))
+    !$omp parallel private(vals,col_inds,nnz,rwnz,thread_upperbound,acc,start_idx,end_idx) &
+    !$omp shared(a,b,c,offsets) 
+    thread_upperbound = 0
+    start_idx = 0
+    !$omp do schedule(static) private(irw, jj, j)
+    do irw = 1, ma
+        if (start_idx == 0) then
+            start_idx = irw
+        end if
+        end_idx = irw
+        do jj = a%irp(irw), a%irp(irw + 1) - 1
+            j = a%ja(jj)
+            thread_upperbound = thread_upperbound + b%irp(j+1) - b%irp(j)
+        end do
+    end do
+    !$omp end do
+    
+    call psb_realloc(thread_upperbound, vals, info)
+    call psb_realloc(thread_upperbound, col_inds, info)
+    
+    ! possible bottleneck
+    acc = 0
+    
+    nnz = 0
+    !$omp do schedule(static) private(irw, jj, j, k)
+    do irw = 1, ma
+        rwnz = 0
+        do jj = a%irp(irw), a%irp(irw + 1) - 1
+            j = a%ja(jj)
+            do k = b%irp(j), b%irp(j + 1) - 1
+                if (acc(b%ja(k)) == 0) then
+                    nnz = nnz + 1
+                    rwnz = rwnz + 1
+                    col_inds(nnz) =  b%ja(k)
+                end if
+                acc(b%ja(k)) = acc(b%ja(k)) + a%val(jj) * b%val(k) 
+            end do
+        end do
+        call psb_qsort(col_inds(nnz - rwnz + 1:nnz))
+        
+        do k = nnz - rwnz + 1, nnz
+            vals(k) = acc(col_inds(k))
+            acc(col_inds(k)) = 0
+        end do
+        c%irp(irw + 1) = rwnz
+    end do
+    !$omp end do
+    
+    offsets(omp_get_thread_num() + 1) = nnz
+    !$omp barrier
+    
+    ! possible bottleneck
+    !$omp single
+    do k = 1, omp_get_num_threads() - 1
+        offsets(k + 1) = offsets(k + 1) + offsets(k)
+    end do
+    !$omp end single
+
+    !$omp barrier
+
+    if (omp_get_thread_num() /= 0) then
+        c%irp(start_idx) = offsets(omp_get_thread_num()) + 1
+    end if
+
+    do irw = start_idx, end_idx - 1
+        c%irp(irw + 1) = c%irp(irw + 1) + c%irp(irw)
+    end do
+
+    !$omp barrier
+
+    !$omp single
+    c%irp(ma + 1) = c%irp(ma + 1) + c%irp(ma)
+    call psb_realloc(c%irp(ma + 1), c%val, info)        
+    call psb_realloc(c%irp(ma + 1), c%ja, info)
+    !$omp end single
+    
+    c%val(c%irp(start_idx):c%irp(start_idx) + nnz) = vals(1:nnz)
+    c%ja(c%irp(start_idx):c%irp(start_idx) + nnz) = col_inds(1:nnz)
+    !$omp end parallel
+  end subroutine spmm_omp_gustavson
+
+  subroutine spmm_omp_gustavson_1d(a,b,c,info)
+    use omp_lib
+
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+    
+    real(psb_dpk_), allocatable :: vals(:), acc(:)
+    integer(psb_ipk_)   :: ma, nb
+    integer(psb_ipk_), allocatable :: col_inds(:), offsets(:)
+    integer(psb_ipk_)   :: irw, jj, j, k, nnz, rwnz, thread_upperbound, &
+                            start_idx, end_idx , blk, blk_size, rwstart,&
+                            rwblk, rwblkrem, nblks
+
+    ma = a%get_nrows()
+    nb = b%get_ncols()
+
+    call c%allocate(ma, nb)
+    c%irp(1) = 1
+
+    ! dense accumulator
+    ! https://sc18.supercomputing.org/proceedings/workshops/workshop_files/ws_lasalss115s2-file1.pdf
+    call psb_realloc(nb, acc, info)
+    allocate(offsets(omp_get_max_threads()))
+
+    nblks = 4 * omp_get_max_threads()
+    rwblk = (ma / nblks)
+    rwblkrem = modulo(ma, nblks)
+    !$omp parallel private(vals,col_inds,nnz,thread_upperbound,acc,start_idx,end_idx) shared(a,b,c,offsets)
+    thread_upperbound = 0
+    start_idx = 0
+    !$omp do schedule(static) private(irw, jj, j)
+    do irw = 1, ma
+        do jj = a%irp(irw), a%irp(irw + 1) - 1
+            j = a%ja(jj)
+            thread_upperbound = thread_upperbound + b%irp(j+1) - b%irp(j)
+        end do
+    end do
+    !$omp end do
+    
+    call psb_realloc(thread_upperbound, vals, info)
+    call psb_realloc(thread_upperbound, col_inds, info)
+    
+    ! possible bottleneck
+    acc = 0
+    
+    nnz = 0
+    !$omp do schedule(static) private(irw,jj,j,k,rwnz,blk,blk_size,rwstart)
+    do blk = 0, nblks - 1
+        if (blk < rwblkrem) then
+            blk_size = rwblk + 1
+            rwstart = blk * rwblk + blk + 1
+        else
+            blk_size = rwblk
+            rwstart = blk * rwblk &
+            + rwblkrem + 1
+        end if
+        do irw = rwstart, rwstart + blk_size - 1
+            if (start_idx == 0) then
+                start_idx = irw
+            end if
+            end_idx = irw
+            rwnz = 0
+            do jj = a%irp(irw), a%irp(irw + 1) - 1
+                j = a%ja(jj)
+                do k = b%irp(j), b%irp(j + 1) - 1
+                    if (acc(b%ja(k)) == 0) then
+                        nnz = nnz + 1
+                        rwnz = rwnz + 1
+                        col_inds(nnz) =  b%ja(k)
+                    end if
+                    acc(b%ja(k)) = acc(b%ja(k)) + a%val(jj) * b%val(k) 
+                end do
+            end do
+            call psb_qsort(col_inds(nnz - rwnz + 1:nnz))
+            
+            do k = nnz - rwnz + 1, nnz
+                vals(k) = acc(col_inds(k))
+                acc(col_inds(k)) = 0
+            end do
+            c%irp(irw + 1) = rwnz
+        end do
+    end do
+    !$omp end do
+    
+    offsets(omp_get_thread_num() + 1) = nnz
+    !$omp barrier
+    
+    ! possible bottleneck
+    !$omp single
+    do k = 1, omp_get_num_threads() - 1
+        offsets(k + 1) = offsets(k + 1) + offsets(k)
+    end do
+    !$omp end single
+
+    !$omp barrier
+
+    if (omp_get_thread_num() /= 0) then
+        c%irp(start_idx) = offsets(omp_get_thread_num()) + 1
+    end if
+
+    do irw = start_idx, end_idx - 1
+        c%irp(irw + 1) = c%irp(irw + 1) + c%irp(irw)
+    end do
+
+    !$omp barrier
+
+    !$omp single
+    c%irp(ma + 1) = c%irp(ma + 1) + c%irp(ma)
+    call psb_realloc(c%irp(ma + 1), c%val, info)        
+    call psb_realloc(c%irp(ma + 1), c%ja, info)
+    !$omp end single
+    
+    c%val(c%irp(start_idx):c%irp(start_idx) + nnz) = vals(1:nnz)
+    c%ja(c%irp(start_idx):c%irp(start_idx) + nnz) = col_inds(1:nnz)
+    !$omp end parallel
+  end subroutine spmm_omp_gustavson_1d
+
+  subroutine spmm_serial_rb_tree(a,b,c,info)
+    use psb_rb_idx_tree_mod
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+
+    integer(psb_ipk_)   :: a_m, b_n
+    integer(psb_ipk_)   :: row, col
+    type(psb_d_rb_idx_tree), allocatable :: row_accs(:)
+
+    a_m = a%get_nrows()
+    b_n = b%get_ncols()
+
+    allocate(row_accs(a_m))
+    call c%allocate(a_m, b_n)
+
+    do row = 1, a_m
+        row_accs(row)%nnz = 0
+        nullify(row_accs(row)%root)
+        do col = a%irp(row), a%irp(row + 1) - 1
+            call psb_rb_idx_tree_scalar_sparse_row_mul(row_accs(row), a%val(col), b, a%ja(col))
+        end do 
+    end do
+    call psb_rb_idx_tree_merge(row_accs, c)
+
+    deallocate(row_accs)
+
+    info = 0
+end subroutine spmm_serial_rb_tree
+
+subroutine spmm_omp_rb_tree(a,b,c,info)
+    use omp_lib
+    use psb_rb_idx_tree_mod
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+
+    integer(psb_ipk_)   :: a_m, b_n
+    integer(psb_ipk_)   :: row, col
+    type(psb_d_rb_idx_tree), allocatable :: row_accs(:)
+    real(8) :: tic, toc
+
+    a_m = a%get_nrows()
+    b_n = b%get_ncols()
+
+    call c%allocate(a_m, b_n)
+
+    allocate(row_accs(a_m))
+    call c%allocate(a_m, b_n)
+
+    !$omp parallel do schedule(static)
+    do row = 1, a_m
+        row_accs(row)%nnz = 0
+        nullify(row_accs(row)%root)
+        do col = a%irp(row), a%irp(row + 1) - 1
+            call psb_rb_idx_tree_scalar_sparse_row_mul(row_accs(row), a%val(col), b, a%ja(col))
+        end do 
+    end do
+    !$omp end parallel do
+
+    call psb_rb_idx_tree_merge(row_accs, c)
+
+    deallocate(row_accs)
+    info = 0
+end subroutine spmm_omp_rb_tree
+
+subroutine compute_indices(a, b, c, info)
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+
+    integer :: full_mat_bound
+    integer :: row, col, i, j, k, nnz
+
+    full_mat_bound = 0
+    !omp parallel do schedule(static) reduction(+:full_mat_bound)
+    do row = 1, a%get_nrows()
+        do col = a%irp(row), a%irp(row + 1) - 1
+            j = a%ja(col)
+            full_mat_bound = full_mat_bound + b%irp(j+1) - b%irp(j)
+        end do
+    end do
+    !omp end parallel do
+
+    call psb_realloc(a%get_nrows() + 1, c%irp, info)
+    call psb_realloc(full_mat_bound, c%ja, info)
+    c%ja = 0
+    c%irp(1) = 1
+
+    nnz = 0
+    
+    do row = 1, a%get_nrows()
+        do col = a%irp(row), a%irp(row + 1) - 1
+            do i = b%irp(a%ja(col)), b%irp(a%ja(col) + 1) - 1
+                k = 0
+                do while(c%ja(c%irp(row) + k) /= 0 .and. c%ja(c%irp(row) + k) /= b%ja(i))
+                    k = k + 1
+                end do
+                if (c%ja(c%irp(row) + k) == 0) then
+                    c%ja(c%irp(row)+k) = b%ja(i)
+                    nnz = nnz + 1
+                end if
+            end do
+        end do
+        c%irp(row + 1) = nnz + 1
+        call psb_qsort(c%ja(c%irp(row):c%irp(row + 1)-1))
+    end do
+
+
+    call psb_realloc(nnz, c%ja, info)
+    call psb_realloc(nnz, c%val, info)
+
+    c%val = 0
+end subroutine compute_indices
+
+subroutine direct_scalar_sparse_row_mul(out_mat, out_row_num, scalar, mat, trgt_row_num)
+    type(psb_d_csr_sparse_mat), intent(inout) :: out_mat
+    integer(psb_ipk_), intent(in) :: out_row_num
+    real(psb_dpk_), intent(in) :: scalar
+    type(psb_d_csr_sparse_mat), intent(in) :: mat
+    integer(psb_ipk_), intent(in) :: trgt_row_num
+
+    integer(psb_ipk_) :: i, k, row_start, row_end
+
+    row_start = out_mat%irp(out_row_num)
+    row_end = out_mat%irp(out_row_num + 1) - 1
+
+    do i = mat%irp(trgt_row_num), mat%irp(trgt_row_num + 1) - 1
+        do k = out_mat%irp(out_row_num), out_mat%irp(out_row_num + 1) - 1
+            if (out_mat%ja(k) == mat%ja(i)) then
+                out_mat%val(k) = out_mat%val(k) + scalar * mat%val(i)
+                exit
+            end if
+        end do
+    end do
+
+end subroutine direct_scalar_sparse_row_mul
+
+subroutine spmm_omp_two_pass(a,b,c,info)
+    use omp_lib
+
+    implicit none
+    type(psb_d_csr_sparse_mat), intent(in) :: a,b
+    type(psb_d_csr_sparse_mat), intent(out):: c
+    integer(psb_ipk_), intent(out) :: info
+
+    integer(psb_ipk_)   :: a_m, b_n, row, col
+
+    a_m = a%get_nrows()
+    b_n = b%get_ncols()
+
+    call c%allocate(a_m, b_n)
+    
+    call compute_indices(a, b, c, info)
+
+    !$omp parallel do schedule(static)
+    do row = 1, a_m
+        do col = a%irp(row), a%irp(row + 1) - 1
+            call direct_scalar_sparse_row_mul(c, row, a%val(col), b, a%ja(col))
+        end do 
+    end do
+    !$omp end parallel do
+end subroutine spmm_omp_two_pass
 
 end subroutine psb_dcsrspspmm
 

base/serial/impl/psb_d_rb_idx_tree_impl.F90

@@ -0,0 +1,284 @@
+subroutine psb_d_rb_idx_tree_insert(this, idx, val)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_insert
+    implicit none
+    class(psb_d_rb_idx_tree), intent(inout) :: this
+    integer(psb_ipk_), intent(in) :: idx
+    real(psb_dpk_), intent(in) :: val
+
+    character(len=22) :: name
+    type(psb_d_rb_idx_node), pointer :: new_node
+    type(psb_d_rb_idx_node), pointer :: current, previous
+    name='psb_rb_idx_tree_insert'
+    
+    allocate(new_node)
+    new_node%idx = idx
+    new_node%val = val
+    nullify(new_node%left)
+    nullify(new_node%right)
+    nullify(new_node%parent)
+    new_node%is_red = .true.
+
+
+    if (.not. associated(this%root)) then
+        this%root => new_node
+        this%nnz = 1
+        new_node%is_red = .false.
+        return
+    end if
+
+    current => this%root
+
+    do while (associated(current))
+        previous => current
+
+        if (idx == current%idx) then
+            current%val = current%val + val
+            deallocate(new_node)
+            return
+        else if (idx < current%idx) then
+            current => current%left
+        else
+
+            current => current%right
+        end if
+    end do
+
+    if (idx < previous%idx) then
+        new_node%parent => previous
+        previous%left => new_node
+    else
+        new_node%parent => previous
+        previous%right => new_node
+    end if
+
+    call psb_d_rb_idx_tree_fix_insertion(this, new_node)
+
+    this%nnz = this%nnz + 1
+end subroutine psb_d_rb_idx_tree_insert
+
+subroutine psb_d_rb_idx_tree_fix_insertion(this, node)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_fix_insertion
+    implicit none
+    class(psb_d_rb_idx_tree), intent(inout) :: this
+    type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+
+    character(len=29) :: name
+    type(psb_d_rb_idx_node), pointer :: current, parent, grand_parent, uncle
+    name = 'psb_rb_idx_tree_fix_insertion'
+
+    current => node
+    parent => current%parent
+    do while(associated(parent) .and. parent%is_red)
+        ! grand parent exist because root can't be red
+        grand_parent => parent%parent
+        if (parent%idx < grand_parent%idx) then
+            uncle => grand_parent%right
+        else
+            uncle => grand_parent%left
+        end if
+
+        if (associated(uncle) .and. uncle%is_red) then
+            parent%is_red = .false.
+            uncle%is_red = .false.
+            grand_parent%is_red = .true.
+            current => grand_parent
+            parent => current%parent
+
+        ! Left-Left case
+        else if (current%idx < parent%idx .and. &
+            parent%idx < grand_parent%idx) then
+            call psb_d_rb_idx_tree_rotate_right(grand_parent)
+            call psb_d_rb_idx_tree_swap_colors(parent, grand_parent)
+
+            if (this%root%idx == grand_parent%idx) this%root => parent
+
+            return
+        ! Left-Right case
+        else if (current%idx > parent%idx .and. &
+            parent%idx < grand_parent%idx) then
+            call psb_d_rb_idx_tree_rotate_left(parent)
+            call psb_d_rb_idx_tree_rotate_right(grand_parent)
+            call psb_d_rb_idx_tree_swap_colors(current, grand_parent)
+
+            if (this%root%idx == grand_parent%idx) this%root => current
+
+            return
+        ! Right-Right case
+        else if (current%idx > parent%idx .and. &
+            parent%idx > grand_parent%idx) then
+            call psb_d_rb_idx_tree_rotate_left(grand_parent)
+            call psb_d_rb_idx_tree_swap_colors(parent, grand_parent)
+
+            if (this%root%idx == grand_parent%idx) this%root => parent
+
+            return
+        ! Right-Left case
+        else
+            call psb_d_rb_idx_tree_rotate_right(parent)
+            call psb_d_rb_idx_tree_rotate_left(grand_parent)
+            call psb_d_rb_idx_tree_swap_colors(current, grand_parent)
+
+            if (this%root%idx == grand_parent%idx) this%root => current
+            
+            return
+        end if
+    end do
+
+    this%root%is_red = .false.
+end subroutine psb_d_rb_idx_tree_fix_insertion
+
+subroutine psb_d_rb_idx_tree_swap_colors(n1, n2)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_swap_colors
+    implicit none
+    type(psb_d_rb_idx_node), pointer, intent(inout) :: n1, n2
+
+    character(len=27) :: name
+    logical :: tmp
+    name='psb_rb_idx_tree_swap_colors'
+
+    tmp = n1%is_red
+    n1%is_red = n2%is_red
+    n2%is_red = tmp
+end subroutine psb_d_rb_idx_tree_swap_colors
+
+subroutine psb_d_rb_idx_tree_rotate_right(node)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_rotate_right
+    implicit none
+    type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+
+    character(len=28) :: name
+    type(psb_d_rb_idx_node), pointer :: l, lr
+    name='psb_rb_idx_tree_rotate_right'
+
+    if (.not. associated(node%left)) return
+
+    l => node%left
+    lr => l%right
+    node%left => lr
+
+    if (associated(lr)) lr%parent => node
+
+    if (associated(node%parent)) then
+        if (node%idx < node%parent%idx) then
+            node%parent%left => l
+        else
+            node%parent%right => l
+        end if
+    end if
+
+    l%parent => node%parent
+    node%parent => l
+
+    l%right => node
+end subroutine psb_d_rb_idx_tree_rotate_right
+
+subroutine psb_d_rb_idx_tree_rotate_left(node)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_rotate_left
+    implicit none
+    type(psb_d_rb_idx_node), pointer, intent(inout) :: node
+
+    character(len=27) :: name
+    type(psb_d_rb_idx_node), pointer :: r, rl
+    name='psb_rb_idx_tree_rotate_left'
+
+    if (.not. associated(node%right)) return
+
+    r => node%right
+    rl => r%left
+    node%right => rl
+
+    if (associated(rl)) rl%parent => node
+
+    if (associated(node%parent)) then
+        if (node%idx < node%parent%idx) then
+            node%parent%left => r
+        else
+            node%parent%right => r
+        end if
+    end if
+
+    r%parent => node%parent
+    node%parent => r
+
+    r%left => node
+end subroutine psb_d_rb_idx_tree_rotate_left
+
+subroutine psb_d_rb_idx_tree_scalar_sparse_row_mul(tree, scalar, mat, row_num)
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_scalar_sparse_row_mul
+    use psb_d_csr_mat_mod, only : psb_d_csr_sparse_mat
+    implicit none
+    type(psb_d_rb_idx_tree), intent(inout) :: tree
+    real(psb_dpk_), intent(in) :: scalar
+    type(psb_d_csr_sparse_mat), intent(in) :: mat
+    integer(psb_ipk_), intent(in) :: row_num
+    
+    character(len=37) :: name
+    integer(psb_ipk_) :: i
+    name='psb_rb_idx_tree_scalar_sparse_row_mul'
+
+    do i = mat%irp(row_num), mat%irp(row_num + 1) - 1
+        call tree%insert(mat%ja(i),scalar * mat%val(i))
+    end do
+
+end subroutine psb_d_rb_idx_tree_scalar_sparse_row_mul
+
+subroutine psb_d_rb_idx_tree_merge(trees, mat)
+#if defined(OPENMP)
+    use omp_lib
+#endif
+    use psb_d_rb_idx_tree_mod, psb_protect_name => psb_d_rb_idx_tree_merge
+    use psb_d_csr_mat_mod, only : psb_d_csr_sparse_mat
+    implicit none
+    type(psb_d_rb_idx_tree), allocatable, intent(inout) :: trees(:)
+    type(psb_d_csr_sparse_mat), intent(inout) :: mat
+
+    character(len=21) :: name
+    integer(psb_ipk_) :: i, j, rows, info, nnz
+    type(psb_d_rb_idx_node), pointer :: current, previous
+    name='psb_rb_idx_tree_merge'
+
+    rows = size(trees)
+
+    mat%irp(1) = 1
+    
+    do i=1, rows
+        mat%irp(i + 1) = mat%irp(i) + trees(i)%nnz
+    end do
+
+    nnz = mat%irp(rows + 1)
+    call psb_realloc(nnz, mat%val, info)
+    call psb_realloc(nnz, mat%ja, info)
+
+#if defined(OPENMP)
+    !$omp parallel do schedule(static), private(current, previous, j)
+#endif
+    do i = 1, size(trees)
+        j = 0
+        current => trees(i)%root
+        do while(associated(current))
+            ! go to the left-most node
+            do while(associated(current%left))
+                current => current%left
+            end do
+            mat%val(j + mat%irp(i)) = current%val
+            mat%ja(j + mat%irp(i)) = current%idx
+            j = j + 1
+
+            previous => current
+            if (associated(current%right)) then
+                if (associated(current%parent)) then
+                    current%parent%left => current%right
+                end if
+                current%right%parent => current%parent
+                current => current%right
+            else
+                current => current%parent
+                if (associated(current)) nullify(current%left)
+            end if
+            deallocate(previous)
+        end do
+    end do
+#if defined(OPENMP)
+    !$omp end parallel do
+#endif
+end subroutine psb_d_rb_idx_tree_merge