[稀疏矩阵] 如何将压缩储存的稀疏矩阵转化为满秩矩阵

program fcode_cn
  Implicit None
  Real , allocatable    :: rMatrix(:,:) , value(:)
  Integer , allocatable :: ipodia(:) , indexJ(:)
  Integer :: N , M , i , j
  Open( 12 , File = "Ipodia.txt")
  Open( 13 , File = "Index J.txt")
  Open( 14 , File = "Value.txt")
  N = GetFileN( 12 )
  M = GetFileN( 13 )
  Allocate( rMatrix(N,N) , ipodia(0:N) , indexJ(M) , value(M) )
  rMatrix   = 0
  ipodia(0) = 0
  Read(12,*) ipodia(1:)
  Read(13,*) indexJ
  Read(14,*) value
  Do i = 1 , N
    rMatrix( indexJ( ipodia(i-1)+1 : ipodia(i) ) , i ) = value( ipodia(i-1)+1 : ipodia(i) )
    rMatrix( i , :i-1 ) = rMatrix( :i-1 , i )
  End Do
  Close(12)
  Close(13)
  Close(14)
  
contains

  Integer Function GetFileN( iFileUnit )
    Integer , Intent( IN ) :: iFileUnit
    character( Len = 1 ) :: cDummy
    integer :: ierr
    GetFileN = 0
    Rewind( iFileUnit )
    Do
      Read( iFileUnit , * , ioStat = ierr ) cDummy
      If( ierr /= 0 ) Exit
      GetFileN = GetFileN + 1
    End Do
    Rewind( iFileUnit )
  End Function GetFileN 
  
end program fcode_cn