#*****************************************************************************80
#
## symdiff_test tests symdiff.
#
#  Licensing:
#
#    Copyright 2016 James P. Howard, II
#
#    The computer code and data files on this web page are distributed under
#    https://opensource.org/licenses/BSD-2-Clause, the BSD-2-Clause license.
#
#  Modified:
#
#    03 March 2020
#
#  Author:
#
#    John Burkardt
#
cat ( date ( ), "\n" )
cat ( "\n" )
cat ( "symdiff_test\n" )
cat ( " ", version$version.string, "\n" )
cat ( "  symdiff applies the symmetric finite difference formula to a function.\n" )

source ( "/home/burkardt/public_html/r_src/symdiff/symdiff.R" )  

cat ( "\n" )

f <- function ( x ) { 3 * x - 1 }
value = symdiff ( f, 4, h = 1 )
cat ( '  symdiff(3*x-1, 4, 1 ) = ', value, "\n" )

value = symdiff ( f, 4, h = 1.0E-06 )
cat ( '  symdiff(3*x-1, 4, 1.0E-06 ) = ', value, "\n" )

value = symdiff ( sin, pi/4, h = 1 )
cat ( '  symdiff(sin, pi/4, 1 ) = ', value, "\n" )
value = symdiff ( sin, pi/4, h = 0.5 )
cat ( '  symdiff(sin, pi/4, 0.5 ) = ', value, "\n" )
value = symdiff ( sin, pi/4, h = 0.01 )
cat ( '  symdiff(sin, pi/4, 0.01 ) = ', value, "\n" )
value = symdiff ( sin, pi/4 )
cat ( '  symdiff(sin, pi/4 ) = ', value, "\n" )
#
#  Terminate.
#
cat ( "\n" )
cat ( "symdiff_test\n" )
cat ( "  Normal end of execution.\n" )
cat ( date ( ), "\n" )

quit ( )