-- rematari.adb

with Text_IO ; use Text_IO ;
with Int_IO ; use Int_IO ;
with Real_IO ; use Real_IO ;

package body Real_Matrix_Arithmetic is

  function "*" ( A , B : Real_Matrix ) return Real_Matrix is

    -- Create an object C for temporary use
    -- The size is based on the formal parameters A and B when called
    C : Real_Matrix ( A'Range(1) , B'Range(2)) ;
  begin

    -- check for legal matrices to multiply 
    if A'Length ( 2 ) /= B'Length ( 1 ) then
      raise Matrix_Error ;
    end if ;

    -- now, compute the product
    for I in A'Range ( 1 ) loop
      for J in B'Range ( 2 ) loop
        C ( I , J ) := 0.0 ;
        for K in A'Range ( 2 ) loop
          C ( I , J ) := C ( I , J ) + A ( I , K ) * 
                         B ( K - A'First(2) + B'First(1) , J) ;
          --                   <-- offset subscript ---> 
          --             all other subscripts are in correct Range
        end loop ;
      end loop ;
    end loop ;
    return C ;
  end ;

  procedure Put ( A : Real_Matrix ;
                  Width : Integer := 3 ;
                  Fore : Integer := 2 ; 
                  Aft : Integer := Real'Digits - 1 ;
                  Exp : Integer := 3 ) is
  begin
    for I in A'Range ( 1 ) loop
      for J in A'Range ( 2 ) loop
        Put ( "MAT(" ) ;
        Put ( I , Width ) ;
        Put ( "," ) ;
        Put ( J , Width ) ;
        Put ( " ) = " ) ;
        Put ( A( I , J ) , Fore , Aft , Exp ) ;
        New_Line ;
      end loop ;
    end loop ;
  end Put ;
end Real_Matrix_Arithmetic ;