program main

c*********************************************************************72
c
cc chebyshev_interp_1d_test() tests chebyshev_interp_1d().
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    14 October 2012
c
c  Author:
c
c    John Burkardt
c
      implicit none

      integer prob
      integer prob_num

      call timestamp ( )
      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'chebyshev_interp_1d_test():'
      write ( *, '(a)' ) '  FORTRAN77 version'
      write ( *, '(a)' ) '  Test chebyshev_interp_1d().'
      write ( *, '(a)' ) 
     &  '  The QR_SOLVE and R8LIB libraries are needed.'
      write ( *, '(a)' ) 
     &  '  The test needs the TEST_INTERP library as well.'

      call p00_prob_num ( prob_num )
      do prob = 1, prob_num
        call test01 ( prob )
      end do
c
c  Terminate.
c
      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'chebyshev_interp_1d_test():'
      write ( *, '(a)' ) '  Normal end of execution.'
      write ( *, '(a)' ) ''
      call timestamp ( )

      return
      end
      subroutine test01 ( prob )

c*********************************************************************72
c
cc TEST01 tests CHEBYSHEV_VALUE_1D.
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    20 September 2012
c
c  Author:
c
c    John Burkardt
c
      implicit none

      integer nd_max
      parameter ( nd_max = 49 )

      integer i
      double precision int_error
      integer nd
      integer ni
      integer prob
      double precision r8vec_norm_affine
      double precision xd(nd_max)
      double precision xi(nd_max)
      double precision xy(2,nd_max)
      double precision yd(nd_max)
      double precision yi(nd_max)

      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'CHEBYSHEV_INTERP_1D_TEST01:'
      write ( *, '(a,i6)' ) 
     &  '  Interpolate data from TEST_INTERP problem #', prob

      call p00_data_num ( prob, nd )
      write ( *, '(a,i6)' ) '  Number of data points = ', nd

      call p00_data ( prob, 2, nd, xy )
      
      call r8mat_transpose_print ( 2, nd, xy, '  Data array:' )

      do i = 1, nd
        xd(i) = xy(1,i)
        yd(i) = xy(2,i)
      end do
c
c  #1:  Does interpolant match function at interpolation points?
c
      ni = nd

      do i = 1, ni
        xi(i) = xd(i)
      end do

      call chebyshev_interp_1d ( nd, xd, yd, ni, xi, yi )

      int_error = r8vec_norm_affine ( ni, yi, yd ) / dble ( ni )

      write ( *, '(a)' ) ''
      write ( *, '(a,g14.6)' ) 
     &  '  L2 interpolation error averaged per interpolant node = ', 
     &  int_error

      return
      end
      subroutine r8mat_transpose_print ( m, n, a, title )

c*********************************************************************72
c
cc r8mat_transpose_print() prints an R8MAT, transposed.
c
c  Discussion:
c
c    An R8MAT is an array of R8's.
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    28 April 2008
c
c  Author:
c
c    John Burkardt
c
c  Parameters:
c
c    Input, integer M, N, the number of rows and columns.
c
c    Input, double precision A(M,N), an M by N matrix to be printed.
c
c    Input, character*(*) TITLE, a title.
c
      implicit none

      integer m
      integer n

      double precision a(m,n)
      character*(*) title

      call r8mat_transpose_print_some ( m, n, a, 1, 1, m, n, title )

      return
      end
      subroutine r8mat_transpose_print_some ( m, n, a, ilo, jlo, ihi,
     &  jhi, title )

c*********************************************************************72
c
cc r8mat_transpose_print_some() prints some of an R8MAT transposed.
c
c  Discussion:
c
c    An R8MAT is an array of R8's.
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    28 April 2008
c
c  Author:
c
c    John Burkardt
c
c  Parameters:
c
c    Input, integer M, N, the number of rows and columns.
c
c    Input, double precision A(M,N), an M by N matrix to be printed.
c
c    Input, integer ILO, JLO, the first row and column to print.
c
c    Input, integer IHI, JHI, the last row and column to print.
c
c    Input, character * ( * ) TITLE, a title.
c
      implicit none

      integer incx
      parameter ( incx = 5 )
      integer m
      integer n

      double precision a(m,n)
      character * ( 14 ) ctemp(incx)
      integer i
      integer i2
      integer i2hi
      integer i2lo
      integer ihi
      integer ilo
      integer inc
      integer j
      integer j2hi
      integer j2lo
      integer jhi
      integer jlo
      character * ( * ) title

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) trim ( title )

      if ( m .le. 0 .or. n .le. 0 ) then
        write ( *, '(a)' ) ' '
        write ( *, '(a)' ) '  (None)'
        return
      end if

      do i2lo = max ( ilo, 1 ), min ( ihi, m ), incx

        i2hi = i2lo + incx - 1
        i2hi = min ( i2hi, m )
        i2hi = min ( i2hi, ihi )

        inc = i2hi + 1 - i2lo

        write ( *, '(a)' ) ' '

        do i = i2lo, i2hi
          i2 = i + 1 - i2lo
          write ( ctemp(i2), '(i8,6x)') i
        end do

        write ( *, '(''       Row'',5a14)' ) ctemp(1:inc)
        write ( *, '(a)' ) '       Col'

        j2lo = max ( jlo, 1 )
        j2hi = min ( jhi, n )

        do j = j2lo, j2hi

          do i2 = 1, inc
            i = i2lo - 1 + i2
            write ( ctemp(i2), '(g14.6)' ) a(i,j)
          end do

          write ( *, '(2x,i8,a,5a14)' ) j, ':', ( ctemp(i), i = 1, inc )

        end do

      end do

      return
      end
      function r8vec_min ( n, a )

c*********************************************************************72
c
cc r8vec_min() returns the minimum value in an R8VEC.
c
c  Discussion:
c
c    An R8VEC is a vector of R8's.
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    18 January 2015
c
c  Author:
c
c    John Burkardt
c
c  Parameters:
c
c    Input, integer N, the number of entries in the array.
c
c    Input, double precision A(N), the array.
c
c    Output, double precision R8VEC_MIN, the value of the smallest entry.
c
      implicit none

      integer n

      double precision a(n)
      integer i
      double precision r8_huge
      parameter ( r8_huge = 1.79769313486231571D+308 )
      double precision r8vec_min
      double precision value

      value = r8_huge
      do i = 1, n
        value = min ( value, a(i) )
      end do

      r8vec_min = value

      return
      end