#! /usr/bin/env python3
#
def circle_arc_grid_display ( r, c, a, ng, cg, filename ):

#*****************************************************************************80
#
## circle_arc_grid_display() displays grid points along a circular arc.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2015
#
#  Author:
#
#    John Burkardt
#
#  Input:
#
#    real R, the radius of the disk.
#
#    real C(2), the coordinates of the center of the disk.
#
#    real A(2), the initial and final angles, in degrees.
#
#    integer NG, the number of grid points inside the disk.
#
#    real CG[NG,2], the grid points.
#
#    string FILENAME, the name of the plotfile to be created.
#
  import matplotlib.pyplot as plt
  import numpy as np
#
#  Make points on the circumference and plot them.
#
  cx = np.zeros ( 51 )
  cy = np.zeros ( 51 )
  angle = np.linspace ( a[0] * np.pi / 180.0, a[1] * np.pi / 180.0, 51 )

  for i in range ( 0, 51 ):
    cx[i] = c[0] + r * np.cos ( angle[i] )
    cy[i] = c[1] + r * np.sin ( angle[i] )

  plt.plot ( cx, cy, linewidth = 2.0, color = 'r' )
#
#  Plot the gridpoints.
#
  plt.plot ( cg[0:ng,0], cg[0:ng,1], 'bs' )
#
#  Cleanup and annotate.
#
  plt.xlabel ( '<---X--->' )
  plt.ylabel ( '<---Y--->' )
  plt.title ( 'Grid points along circular arc' )
  plt.grid ( True )
  plt.axis ( 'equal' )
# plt.show ( )
#
#  Save plot to file.
#
  plt.savefig ( filename )
  plt.show ( block = False )
  plt.close ( )

  print ( '' )
  print ( '  Graphics data saved in file "%s"' % (filename ) )

  return

def circle_arc_grid_display_test ( ):

#*****************************************************************************80
#
## circle_arc_grid_display() displays grid points along a circular arc.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2015
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'circle_arc_grid_display_test():' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  circle_arc_grid_display() displays a grid of points along a circular arc.' )

  r = 3.0
  c = np.array ( [ 4.0, 6.0 ] )
  a = np.array ( [ -30.0, 120.0 ] )
  n = 20
#
#  Compute the data.
#
  xy = circle_arc_grid_points ( r, c, a, n )
#
#  Plot the data.
#
  filename = 'circle_arc_grid_display.png'
  circle_arc_grid_display ( r, c, a, n, xy, filename )
#
#  Terminate.
#
  print ( '' )
  print ( 'circle_arc_grid_display_test():' )
  print ( '  Normal end of execution.' )
  return
  
def circle_arc_grid_points ( r, c, a, n ):

#*****************************************************************************80
#
## circle_arc_grid_points() computes grid points along a circular arc.
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    17 April 2015
#
#  Author:
#
#    John Burkardt
#
#  Input:
#
#    real R, the radius of the circle.
#
#    real C(2), the coordinates of the center.
#
#    real A(2), the angle of the first and last
#    points, in DEGREES.
#
#    integer N, the number of points.
#
#  Output:
#
#    Output, real XY[N,2], the grid points.
#
  import numpy as np

  xy = np.zeros ( ( n, 2 ) )

  angle = np.linspace ( a[0] * np.pi / 180.0, a[1] * np.pi / 180.0, n )

  for i in range ( 0, n ):
    xy[i,0] = c[0] + r * np.cos ( angle[i] )
    xy[i,1] = c[1] + r * np.sin ( angle[i] )

  return xy

def circle_arc_grid_points_test ( ):

#*****************************************************************************80
#
## circle_arc_grid_points_test() tests circle_arc_grid_points().
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    17 April 2015
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'circle_arc_grid_points_test():' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  circle_arc_grid_points() returns points along a circular arc.' )
  print ( '  In this example, we compute points on a 90 degree arc.' )

  r = 2.0
  c = np.array ( [ 5.0, 5.0 ] )
  a = np.array ( [ 0.0, 90.0 ] )
  n = 20;
#
#  Echo the input.
#
  print ( '' )
  print ( '  Radius =           %g' % ( r ) )
  print ( '  Center =           %g  %g\n' % ( c[0], c[1] ) )
  print ( '  Angle 1 =          %g' % ( a[0] ) )
  print ( '  Angle 2 =          %g' % ( a[1] ) )
  print ( '  Number of points = %d' % ( n ) )
#
#  Compute the data.
#
  xy = circle_arc_grid_points ( r, c, a, n )
#
#  Print a little of the data.
#
  r82col_print_part ( n, xy, 10, '  Some points on the arc:' )
#
#  Write the data.
#
  filename = 'circle_arc_grid_points.xy'
  r8mat_write ( filename, n, 2, xy )
  print ( ' ' )
  print ( '  Data written to "%s"' % ( filename ) )
#
#  Plot the data.
#
  filename = 'circle_arc_grid_points.png'
  circle_arc_grid_display ( r, c, a, n, xy, filename )
  print ( '' )
  print ( '  Plot saved in file "%s"' % ( filename ) )

  return
  
def circle_arc_grid_test ( ):

#*****************************************************************************80
#
## circle_arc_grid_test() tests circle_arc_grid().
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    17 April 2015
#
#  Author:
#
#    John Burkardt
#
  import platform

  print ( '' )
  print ( 'circle_arc_grid_test():' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  Test circle_arc_grid().' )
#
#  Utilities:
#
  r82col_print_part_test ( )
  r8mat_write_test ( )
#
#  Library.
#
  circle_arc_grid_display_test ( )
  circle_arc_grid_points_test ( )
#
#  Terminate.
#
  print ( '' )
  print ( 'circle_arc_grid_test():' )
  print ( '  Normal end of execution.' )
  return

def r82col_print_part ( n, a, max_print, title ):

#*****************************************************************************80
#
## r82col_print_part() prints "part" of an R82COL.
#
#  Discussion:
#
#    An R82COL is an (N,2) array of R8's.
#
#    The user specifies MAX_PRINT, the maximum number of lines to print.
#
#    If N, the size of the vector, is no more than MAX_PRINT, then
#    the entire vector is printed, one entry per line.
#
#    Otherwise, if possible, the first MAX_PRINT-2 entries are printed,
#    followed by a line of periods suggesting an omission,
#    and the last entry.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    19 December 2001
#
#  Author:
#
#    John Burkardt
#
#  Input:
#
#    integer N, the number of entries of the vector.
#
#    real A(N,2), the vector to be printed.
#
#    integer MAX_PRINT, the maximum number of lines
#    to print.
#
#    string TITLE, a title.
#
  if ( 0 < max_print ):

    if ( 0 < n ):

      if ( 0 < len ( title ) ):
        print ( '' )
        print ( title )

      print ( '' )

      if ( n <= max_print ):

        for i in range ( 0, n ):
          print ( '  %4d  %14g  %14g' % ( i, a[i,0], a[i,1] ) )
 
      elif ( 3 <= max_print ):

        for i in range ( 0, max_print - 2 ):
          print ( '  %4d  %14g  %14g' % ( i, a[i,0], a[i,1] ) )
        print ( '  ....  ..............  ..............' )
        i = n - 1
        print ( '  %4d  %14g  %14g' % ( i, a[i,0], a[i,1] ) )

      else:

        for i in range ( 0, max_print - 1 ):
          print ( '  %4d  %14g  %14g' % ( i, a[i,0], a[i,1] ) )
        i = max_print - 1
        print ( '  %4d  %14g  %14g  ...more entries...' % ( i, a[i,0], a[i,1] ) )

  return

def r82col_print_part_test ( ):

#*****************************************************************************80
#
## r82col_print_part_test() tests r82col_print_part().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    09 April 2015
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'r82col_print_part_test()' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  r82col_print_part() prints an R82COL.' )

  n = 10

  v = np.array ( [ \
    [  11,  12 ], \
    [  21,  22 ], \
    [  31,  32 ], \
    [  41,  42 ], \
    [  51,  52 ], \
    [  61,  62 ], \
    [  71,  72 ], \
    [  81,  82 ], \
    [  91,  92 ], \
    [ 101, 102 ] ] )

  max_print = 2
  r82col_print_part ( n, v, max_print, '  Output with MAX_PRINT = 2' )

  max_print = 5
  r82col_print_part ( n, v, max_print, '  Output with MAX_PRINT = 5' )

  max_print = 25
  r82col_print_part ( n, v, max_print, '  Output with MAX_PRINT = 25' )

  return

def r8mat_write ( filename, m, n, a ):

#*****************************************************************************80
#
## r8mat_write() writes an R8MAT to a file.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    12 October 2014
#
#  Author:
#
#    John Burkardt
#
#  Input:
#
#    string FILENAME, the name of the output file.
#
#    integer M, the number of rows in A.
#
#    integer N, the number of columns in A.
#
#    real A(M,N), the matrix.
#
  output = open ( filename, 'w' )

  for i in range ( 0, m ):
    for j in range ( 0, n ):
      s = '  %g' % ( a[i,j] )
      output.write ( s )
    output.write ( '\n' )

  output.close ( )

  return

def r8mat_write_test ( ):

#*****************************************************************************80
#
## r8mat_write_test() tests r8mat_write().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    12 October 2014
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'R8MAT_WRITE_TEST:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  Test R8MAT_WRITE, which writes an R8MAT to a file.' )

  filename = 'r8mat_write_test.txt'
  m = 5
  n = 3
  a = np.array ( (  \
    ( 1.1, 1.2, 1.3 ), \
    ( 2.1, 2.2, 2.3 ), \
    ( 3.1, 3.2, 3.3 ), \
    ( 4.1, 4.2, 4.3 ), \
    ( 5.1, 5.2, 5.3 ) ) )
  r8mat_write ( filename, m, n, a )

  print ( '' )
  print ( '  Created file "%s".' % ( filename ) )

  return
  
def timestamp ( ):

#*****************************************************************************80
#
## timestamp() prints the date as a timestamp.
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    06 April 2013
#
#  Author:
#
#    John Burkardt
#
  import time

  t = time.time ( )
  print ( time.ctime ( t ) )

  return

if ( __name__ == '__main__' ):
  timestamp ( )
  circle_arc_grid_test ( )
  timestamp ( )