program main

c*********************************************************************72
c
cc MAIN is the main program for MACHINE_PRB.
c
c  Discussion:
c
c    MACHINE_PRB tests the MACHINE library.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license. 
c
c  Modified:
c
c    27 March 2006
c
c  Author:
c
c    John Burkardt
c
      implicit none

      call timestamp ( )
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'MACHINE_PRB:'
      write ( *, '(a)' ) '  FORTRAN77 version'
      write ( *, '(a)' ) '  Test the MACHINE library.'

      call d1mach_test ( )
      call i1mach_test ( )
      call r1mach_test ( )
c
c  Terminate.
c
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'MACHINE_PRB:'
      write ( *, '(a)' ) '  Normal end of execution.'
      write ( *, '(a)' ) ' '
      call timestamp ( )

      stop
      end
      subroutine d1mach_test ( )

c*********************************************************************72
c
cc D1MACH_TEST reports the constants returned by D1MACH.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license. 
c
c  Modified:
c
c    27 March 2006
c
c  Author:
c
c    John Burkardt
c
      implicit none

      double precision d1mach

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'D1MACH_TEST'
      write ( *, '(a)' ) '  D1MACH returns constants associated with'
      write ( *, '(a)' ) '  real double precision computer arithmetic.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  Assume that double precision numbers are'
      write ( *, '(a)' ) 
     &  '  stored with a mantissa of T digits in base B,'
      write ( *, '(a)' ) '  with an exponent whose value is between '
      write ( *, '(a)' ) '  EMIN and EMAX.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  For input arguments of 1 <= I <= 5,'
      write ( *, '(a)' ) '  D1MACH will return the following values:'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  D1MACH(1) = B^(EMIN-1), the smallest positive magnitude.'
      write ( *, * ) d1mach(1)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  D1MACH(2) = B^EMAX*(1-B^(-T)), the largest magnitude.'
      write ( *, * ) d1mach(2)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  D1MACH(3) = B^(-T), the smallest relative spacing.'
      write ( *, * ) d1mach(3)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  D1MACH(4) = B^(1-T), the largest relative spacing.'
      write ( *, * ) d1mach(4)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  D1MACH(5) = log10(B).'
      write ( *, * ) d1mach(5)

      return
      end
      subroutine i1mach_test ( )

c*********************************************************************72
c
cc I1MACH_PRB reports the constants returned by I1MACH.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license. 
c
c  Modified:
c
c    27 March 2006
c
c  Author:
c
c    John Burkardt
c
      implicit none

      integer i1mach

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'I1MACH_TEST'
      write ( *, '(a)' ) '  I1MACH returns constants associated with'
      write ( *, '(a)' ) '  integer computer arithmetic, as well as'
      write ( *, '(a)' ) '  integers associated with real or double'
      write ( *, '(a)' ) '  precision calculations, and input/output.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  Numbers associated with input/output units:'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(1) = the standard input unit.'
      write ( *,     * ) i1mach(1)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(2) = the standard output unit.'
      write ( *,     * ) i1mach(2)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(3) = the standard punch unit.'
      write ( *,     * ) i1mach(3)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  I1MACH(4) = the standard error message unit.'
      write ( *,     * ) i1mach(4)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  Numbers associated with words:'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(5) = the number of bits per integer.'
      write ( *,     * ) i1mach(5)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  I1MACH(6) = the number of characters per integer.'
      write ( *,     * ) i1mach(6)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  Numbers associated with integer values:'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Assume integers are represented in the S digit '
      write ( *, '(a)' ) '  base A form:'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '    Sign * (X(S-1)*A^(S-1) + ... + X(1)*A + X(0))'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  where the digits X satisfy 0 <= X(1:S-1) < A.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(7) = A, the base.'
      write ( *,     * ) i1mach(7)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(8) = S, the number of base A digits.'
      write ( *,     * ) i1mach(8)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(9) = A^S-1, the largest integer.'
      write ( *,     * ) i1mach(9)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Numbers associated with floating point values:'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Assume floating point numbers are represented '
      write ( *, '(a)' ) '  in the T digit base B form:'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '    Sign * (B^E) * ((X(1)/B) + ... + (X(T)/B^T) )'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  where '
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '    0 <= X(1:T) < B,'
      write ( *, '(a)' ) 
     &  '    0 < X(1) (unless the value being represented is 0),'
      write ( *, '(a)' ) '    EMIN <= E <= EMAX.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(10) = B, the base.'
      write ( *,     * ) i1mach(10)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Numbers associated with single precision values:'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  I1MACH(11) = T, the number of base B digits.'
      write ( *,     * ) i1mach(11)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(12) = EMIN, the smallest exponent E.'
      write ( *,     * ) i1mach(12)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(13) = EMAX, the largest exponent E.'
      write ( *,     * ) i1mach(13)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Numbers associated with double precision values:'
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  I1MACH(14) = T, the number of base B digits.'
      write ( *,     * ) i1mach(14)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(15) = EMIN, the smallest exponent E.'
      write ( *,     * ) i1mach(15)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  I1MACH(16) = EMAX, the largest exponent E.'
      write ( *,     * ) i1mach(16)

      return
      end
      subroutine r1mach_test ( )

c*********************************************************************72
c
cc R1MACH_PRB reports the constants returned by R1MACH.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license. 
c
c  Modified:
c
c    27 March 2006
c
c  Author:
c
c    John Burkardt
c
      implicit none

      real r1mach

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'R1MACH_TEST'
      write ( *, '(a)' ) '  R1MACH returns constants associated with'
      write ( *, '(a)' ) '  real single precision computer arithmetic.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  Assume that single precision numbers are'
      write ( *, '(a)' ) 
     &  '  stored with a mantissa of T digits in base B,'
      write ( *, '(a)' ) '  with an exponent whose value is between '
      write ( *, '(a)' ) '  EMIN and EMAX.'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  For input arguments of 1 <= I <= 5,'
      write ( *, '(a)' ) '  R1MACH will return the following values:'

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  R1MACH(1) = B^(EMIN-1), the smallest positive magnitude.'
      write ( *, * ) r1mach(1)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  R1MACH(2) = B^EMAX*(1-B^(-T)), the largest magnitude.'
      write ( *, * ) r1mach(2)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  R1MACH(3) = B^(-T), the smallest relative spacing.'
      write ( *, * ) r1mach(3)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  R1MACH(4) = B^(1-T), the largest relative spacing.'
      write ( *, * ) r1mach(4)

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) '  R1MACH(5) = log10(B).'
      write ( *, * ) r1mach(5)

      return
      end