prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  DOC: private methods used in cookbook recipe
  ### Bug report
  
  **Bug summary**
  
  in #2567, `doc/source/cookbook/render_two_fields_tf.py` was added to the cookbook
  On the two following lines, the private method `_get_field_info` is used
  https://github.com/yt-project/yt/blob/ef08989d8222e7172751d17009959102db05dd20/doc/source/cookbook/render_two_fields_tf.py#L15
  https://github.com/yt-project/yt/blob/ef08989d8222e7172751d17009959102db05dd20/doc/source/cookbook/render_two_fields_tf.py#L30
  
  This should be refactored to avoid showing private elements
  @zingale, do you know how we could do this ?
  
  </issue>
  <code>
  [start of doc/source/cookbook/render_two_fields_tf.py]
  1 import numpy as np
  2 
  3 import yt
  4 from yt.visualization.volume_rendering.api import Scene, create_volume_source
  5 
  6 ds = yt.load("IsolatedGalaxy/galaxy0030/galaxy0030")
  7 
  8 # create a scene and add volume sources to it
  9 
  10 sc = Scene()
  11 
  12 # Add density
  13 
  14 field = "density"
  15 ds._get_field_info(field).take_log = True
  16 
  17 vol = create_volume_source(ds, field=field)
  18 vol.use_ghost_zones = True
  19 
  20 tf = yt.ColorTransferFunction([-28, -25])
  21 tf.clear()
  22 tf.add_layers(4, 0.02, alpha=np.logspace(-3, -1, 4), colormap="winter")
  23 
  24 vol.set_transfer_function(tf)
  25 sc.add_source(vol)
  26 
  27 # Add temperature
  28 
  29 field = "temperature"
  30 ds._get_field_info(field).take_log = True
  31 
  32 vol2 = create_volume_source(ds, field=field)
  33 vol2.use_ghost_zones = True
  34 
  35 tf = yt.ColorTransferFunction([4.5, 7.5])
  36 tf.clear()
  37 tf.add_layers(4, 0.02, alpha=np.logspace(-0.2, 0, 4), colormap="autumn")
  38 
  39 vol2.set_transfer_function(tf)
  40 sc.add_source(vol2)
  41 
  42 # setup the camera
  43 
  44 cam = sc.add_camera(ds, lens_type="perspective")
  45 cam.resolution = (1600, 900)
  46 cam.zoom(20.0)
  47 
  48 # Render the image.
  49 
  50 sc.render()
  51 
  52 sc.save_annotated(
  53     "render_two_fields_tf.png",
  54     sigma_clip=6.0,
  55     tf_rect=[0.88, 0.15, 0.03, 0.8],
  56     render=False,
  57 )
  58
  [end of doc/source/cookbook/render_two_fields_tf.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/doc/source/cookbook/render_two_fields_tf.py b/doc/source/cookbook/render_two_fields_tf.py
  --- a/doc/source/cookbook/render_two_fields_tf.py
  +++ b/doc/source/cookbook/render_two_fields_tf.py
  @@ -12,7 +12,6 @@
   # Add density
   
   field = "density"
  -ds._get_field_info(field).take_log = True
   
   vol = create_volume_source(ds, field=field)
   vol.use_ghost_zones = True
  @@ -27,7 +26,6 @@
   # Add temperature
   
   field = "temperature"
  -ds._get_field_info(field).take_log = True
   
   vol2 = create_volume_source(ds, field=field)
   vol2.use_ghost_zones = True
  
verification_info: {"golden_diff": "diff --git a/doc/source/cookbook/render_two_fields_tf.py b/doc/source/cookbook/render_two_fields_tf.py\n--- a/doc/source/cookbook/render_two_fields_tf.py\n+++ b/doc/source/cookbook/render_two_fields_tf.py\n@@ -12,7 +12,6 @@\n # Add density\n \n field = \"density\"\n-ds._get_field_info(field).take_log = True\n \n vol = create_volume_source(ds, field=field)\n vol.use_ghost_zones = True\n@@ -27,7 +26,6 @@\n # Add temperature\n \n field = \"temperature\"\n-ds._get_field_info(field).take_log = True\n \n vol2 = create_volume_source(ds, field=field)\n vol2.use_ghost_zones = True\n", "issue": "DOC: private methods used in cookbook recipe\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nin #2567, `doc/source/cookbook/render_two_fields_tf.py` was added to the cookbook\r\nOn the two following lines, the private method `_get_field_info` is used\r\nhttps://github.com/yt-project/yt/blob/ef08989d8222e7172751d17009959102db05dd20/doc/source/cookbook/render_two_fields_tf.py#L15\r\nhttps://github.com/yt-project/yt/blob/ef08989d8222e7172751d17009959102db05dd20/doc/source/cookbook/render_two_fields_tf.py#L30\r\n\r\nThis should be refactored to avoid showing private elements\r\n@zingale, do you know how we could do this ?\n", "before_files": [{"content": "import numpy as np\n\nimport yt\nfrom yt.visualization.volume_rendering.api import Scene, create_volume_source\n\nds = yt.load(\"IsolatedGalaxy/galaxy0030/galaxy0030\")\n\n# create a scene and add volume sources to it\n\nsc = Scene()\n\n# Add density\n\nfield = \"density\"\nds._get_field_info(field).take_log = True\n\nvol = create_volume_source(ds, field=field)\nvol.use_ghost_zones = True\n\ntf = yt.ColorTransferFunction([-28, -25])\ntf.clear()\ntf.add_layers(4, 0.02, alpha=np.logspace(-3, -1, 4), colormap=\"winter\")\n\nvol.set_transfer_function(tf)\nsc.add_source(vol)\n\n# Add temperature\n\nfield = \"temperature\"\nds._get_field_info(field).take_log = True\n\nvol2 = create_volume_source(ds, field=field)\nvol2.use_ghost_zones = True\n\ntf = yt.ColorTransferFunction([4.5, 7.5])\ntf.clear()\ntf.add_layers(4, 0.02, alpha=np.logspace(-0.2, 0, 4), colormap=\"autumn\")\n\nvol2.set_transfer_function(tf)\nsc.add_source(vol2)\n\n# setup the camera\n\ncam = sc.add_camera(ds, lens_type=\"perspective\")\ncam.resolution = (1600, 900)\ncam.zoom(20.0)\n\n# Render the image.\n\nsc.render()\n\nsc.save_annotated(\n    \"render_two_fields_tf.png\",\n    sigma_clip=6.0,\n    tf_rect=[0.88, 0.15, 0.03, 0.8],\n    render=False,\n)\n", "path": "doc/source/cookbook/render_two_fields_tf.py"}]}