#*****************************************************************************80
#
## predator_plot3d computes time/predator/prey data and makes a 3D plot.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    01 September 2020
#
#  Author:
#
#    John Burkardt
#
library ( 'plot3D' )

cat ( "\n" )
cat ( "predator_plot3d:\n" )
cat ( " ", version$version.string, "\n" )
cat ( "  Model the interaction between rabbits and foxes.\n" )
#
#  Read the data.
#
filename = 'predator_data.txt'
trf <- read.table ( file = filename, header = FALSE )
#
filename = 'predator_plot3d.png'
png ( filename )

lines3D ( trf[,2], trf[,3], trf[,1],
  theta = 60,
  phi = 30,
  main = "Predator/prey evolution",
  xlab = "<-- rabbits -->",
  ylab = "<-- foxes -->",
  zlab = "<-- time -->",
  lwd = 3,
  col = "red" )

cat ( "\n" )
cat ( "  Graphics saved as '", filename, "'\n" )
#
#  Terminate.
#
cat ( "\n" )
cat ( "predator_plot3d:\n" )
cat ( "  Normal end of execution.\n" )

quit ( )