[yt-svn] commit/yt: ngoldbaum: Merged in atmyers/yt (pull request #2018)

[commits-noreply at bitbucket.org]

1 new commit in yt:

https://bitbucket.org/yt_analysis/yt/commits/c74d00a0b3ce/
Changeset:   c74d00a0b3ce
Branch:      yt
User:        ngoldbaum
Date:        2016-03-09 17:40:20+00:00
Summary:     Merged in atmyers/yt (pull request #2018)

Add an example of changing the scale keyword argument to the Transfer Function Tutorial. Closes Issue #1098.
Affected #:  1 file

diff -r aef6b376c4a5cb8e3ec8a3434e29435f142ad997 -r c74d00a0b3ce8086dc90a2734061a524c6ff277e doc/source/visualizing/TransferFunctionHelper_Tutorial.ipynb
--- a/doc/source/visualizing/TransferFunctionHelper_Tutorial.ipynb
+++ b/doc/source/visualizing/TransferFunctionHelper_Tutorial.ipynb
@@ -4,7 +4,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Here, we explain how to use TransferFunctionHelper to visualize and interpret yt volume rendering transfer functions.  TransferFunctionHelper is a utility class that makes it easy to visualize he probability density functions of yt fields that you might want to volume render.  This makes it easier to choose a nice transfer function that highlights interesting physical regimes.\n",
+    "Here, we explain how to use TransferFunctionHelper to visualize and interpret yt volume rendering transfer functions.  Creating a custom transfer function is a process that usually involves some trial-and-error. TransferFunctionHelper is a utility class designed to help you visualize the probability density functions of yt fields that you might want to volume render.  This makes it easier to choose a nice transfer function that highlights interesting physical regimes.\n",
     "\n",
     "First, we set up our namespace and define a convenience function to display volume renderings inline in the notebook.  Using `%matplotlib inline` makes it so matplotlib plots display inline in the notebook."
    ]
@@ -132,8 +132,8 @@
     "tfh.set_log(True)\n",
     "tfh.build_transfer_function()\n",
     "tfh.tf.add_layers(8, w=0.01, mi=4.0, ma=8.0, col_bounds=[4.,8.], alpha=np.logspace(-1,2,7), colormap='RdBu_r')\n",
-    "tfh.tf.map_to_colormap(6.0, 8.0, colormap='Reds', scale=10.0)\n",
-    "tfh.tf.map_to_colormap(-1.0, 6.0, colormap='Blues_r', scale=1.)\n",
+    "tfh.tf.map_to_colormap(6.0, 8.0, colormap='Reds')\n",
+    "tfh.tf.map_to_colormap(-1.0, 6.0, colormap='Blues_r')\n",
     "\n",
     "tfh.plot(profile_field='cell_mass')"
    ]
@@ -142,7 +142,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Finally, let's take a look at the volume rendering. First use the helper function to create a default rendering, then we override this with the transfer function we just created."
+    "Let's take a look at the volume rendering. First use the helper function to create a default rendering, then we override this with the transfer function we just created."
    ]
   },
   {
@@ -166,7 +166,55 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "We can clearly see that the hot gas is mostly associated with bound structures while the cool gas is associated with low-density voids."
+    "That looks okay, but the red gas (associated with temperatures between 1e6 and 1e8 K) is a bit hard to see in the image. To fix this, we can make that gas contribute a larger alpha value to the image by using the ``scale`` keyword argument in ``map_to_colormap``."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "tfh2 = TransferFunctionHelper(ds)\n",
+    "tfh2.set_field('temperature')\n",
+    "tfh2.set_bounds()\n",
+    "tfh2.set_log(True)\n",
+    "tfh2.build_transfer_function()\n",
+    "tfh2.tf.add_layers(8, w=0.01, mi=4.0, ma=8.0, col_bounds=[4.,8.], alpha=np.logspace(-1,2,7), colormap='RdBu_r')\n",
+    "tfh2.tf.map_to_colormap(6.0, 8.0, colormap='Reds', scale=5.0)\n",
+    "tfh2.tf.map_to_colormap(-1.0, 6.0, colormap='Blues_r', scale=1.0)\n",
+    "\n",
+    "tfh2.plot(profile_field='cell_mass')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Note that the height of the red portion of the transfer function has increased by a factor of 5.0. If we use this transfer function to make the final image:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "source.set_transfer_function(tfh2.tf)\n",
+    "im3 = sc.render()\n",
+    "\n",
+    "showme(im3[:,:,:3])"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The red gas is now much more prominant in the image. We can clearly see that the hot gas is mostly associated with bound structures while the cool gas is associated with low-density voids."
    ]
   }
  ],

Repository URL: https://bitbucket.org/yt_analysis/yt/

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