Added function to expand matrix.

Compress_Matrix.f90

@@ -16,6 +16,11 @@ subroutine Compress_Matrix(c, a)
 
   n = size(a, 1)
 
+  !------------------------------------!
+  !   Stored dimension of the matrix   !
+  !------------------------------------!
+  c % n = n
+
   !----------------------------------------!
   !   Count non-zero terms in the matrix   !
   !----------------------------------------!

Driver.f90

@@ -16,6 +16,7 @@ program Driver
   include "Matrix_Vector_Multiply.int"
   include "Transpose_Matrix.int" 
   include "Compress_Matrix.int"               
+  include "Expand_Matrix.int"               
 !-----------------------------------[Locals]-----------------------------------!
   integer :: row, col, choice, i
 !==============================================================================!
@@ -47,10 +48,11 @@ program Driver
   data (a2(7,col), col=1,n2) /  0.,  0., -1.,  0., -3., -4., 44. /  ! =--> row 7
   data (b2(row),   row=1,n2) /  1.,  2.,  3.,  4.,  3.,  2.,  1. /
 
-!-------------------!                   
-! Compressed matrix !
-!-------------------!
-  type(Matrix) :: ac2
+!----------------------------------------! 
+! Matrices for compressing and expanding !
+!----------------------------------------!
+  type(Matrix)      :: ac3
+  real, allocatable :: a3(:,:)
 !------------------------------------------------------------------------------!
 
   write(*,*) '============================'
@@ -109,28 +111,36 @@ program Driver
     call Print_Vector("Vector y2 should recover the source term:", y2)
   end if
 
+  !---------------------------------------------------!
+  !   Demonstrate compressing and expanding matrices  !
+  !---------------------------------------------------!
   if(choice == 3) then
 
     call Print_Matrix("Original matrix a2", a2)
 
-    ! Compress matrix "a2" and store it in "ac2"
-    call Compress_Matrix(ac2, a2)
+    ! Compress matrix "a2" and store it in "ac3"
+    call Compress_Matrix(ac3, a2)
 
-    call Print_Vector("ac2 % val:", ac2 % val)
+    call Print_Vector("ac3 % val:", ac3 % val)
 
-    write(*,*) "ac2 % col = "
-    do i=1, size(ac2 % col)
-      write(*,'(2I4)'), i, ac2 % col(i)
+    write(*,*) "ac3 % col = "
+    do i=1, size(ac3 % col)
+      write(*,'(2I4)'), i, ac3 % col(i)
     end do 
-    write(*,*) "ac2 % row = "
-    do i=1, size(ac2 % row)
-      write(*,'(2I4)'), i, ac2 % row(i)
+    write(*,*) "ac3 % row = "
+    do i=1, size(ac3 % row)
+      write(*,'(2I4)'), i, ac3 % row(i)
     end do 
-    write(*,*) "ac2 % dia = "
-    do i=1, size(ac2 % dia)
-      write(*,'(2I4)'), i, ac2 % dia(i)
+    write(*,*) "ac3 % dia = "
+    do i=1, size(ac3 % dia)
+      write(*,'(2I4)'), i, ac3 % dia(i)
     end do 
 
+    ! Expand matrix "ac2" and store it in "a3"
+    call Expand_Matrix(a3, ac3)
+
+    call Print_Matrix("Epanded matrix ac3:", a3)
+
   end if
 
   end program Driver

Expand_Matrix.f90

@@ -0,0 +1,36 @@
+!==============================================================================!
+  subroutine Expand_Matrix(a, c)
+!------------------------------------------------------------------------------!
+!----------------------------------[Modules]-----------------------------------!
+  use Matrix_Mod
+!------------------------------------------------------------------------------!
+  implicit none
+!------------------------------------------------------------------------------!
+  real, allocatable :: a(:,:)
+  type(Matrix)      :: c
+!------------------------------------------------------------------------------!
+  integer :: row, col  ! row used to be "i", col used to be "j"
+  integer :: n, pos
+  integer :: non_zeros
+!==============================================================================!
+
+  n = c % n
+
+  !---------------------!
+  !   Allocate memory   !
+  !---------------------!
+  allocate (a(n,n));   
+  a = 0.0
+
+  !------------------------------!
+  !   Form the expanded matrix   !
+  !------------------------------!
+  pos = 1
+  do row = 1, n                                  ! browse through rows
+    do pos = c % row(row), c % row(row + 1) - 1  ! brows through columns
+      col = c % col(pos)                         ! take the real column number
+      a(row, col) = c % val(pos)
+    end do       
+  end do           
+
+  end subroutine Expand_Matrix

Expand_Matrix.int

@@ -0,0 +1,8 @@
+interface
+  subroutine Expand_Matrix(a, c)
+    use Matrix_Mod
+    implicit none
+    real, allocatable :: a(:,:)
+    type(Matrix)      :: c
+  end subroutine Expand_Matrix
+end interface

Makefile.am

@@ -10,6 +10,7 @@ SFS_SOURCES =			\
   Cholesky_Factorization_U.f90	\
   Compress_Matrix.f90		\
   Driver.f90             	\
+  Expand_Matrix.f90		\
   Forward_Substitution.f90	\
   Forward_Substitution_L.f90	\
   Forward_Substitution_U.f90	\

Matrix_Mod.f90

@@ -30,11 +30,12 @@ module Matrix_Mod
 !   A % dia = [   1   5   9  12 ]                                              !
 !==============================================================================!
   type Matrix
-    integer              :: nonzeros               ! number of nonzero entries
-    real,    allocatable :: val(:)                 ! value
-    integer, allocatable :: col(:)                 ! beginning of each row   
-    integer, allocatable :: row(:)                 ! column positions
-    integer, allocatable :: dia(:)                 ! diagonal positions 
+    integer              :: n         ! matrix dimension
+    integer              :: nonzeros  ! number of nonzero entries
+    real,    allocatable :: val(:)    ! value
+    integer, allocatable :: col(:)    ! beginning of each row   
+    integer, allocatable :: row(:)    ! column positions
+    integer, allocatable :: dia(:)    ! diagonal positions 
   end type Matrix
 
 end module Matrix_Mod