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<section id="layer-activations">
<span id="activations"></span><h1>Layer Activations<a class="headerlink" href="#layer-activations" title="Permalink to this heading">¶</a></h1>
<p>Investigating the latent space of a neural network can provide useful insights into the structure of your data and what models have learned during training. Slideflow provides several tools for post-hoc latent space analysis of trained neural networks, primarily by calculating activations at one or more neural network layers for all images in a dataset. In the next sections, we will take a look at how these layer activations can be calculated for downstream analysis and provide examples of analyses that can be performed.</p>
<section id="calculating-layer-activations">
<h2>Calculating Layer Activations<a class="headerlink" href="#calculating-layer-activations" title="Permalink to this heading">¶</a></h2>
<p>Activations at one or more layers of a trained network can be calculated with <a class="reference internal" href="../model/#slideflow.model.Features" title="slideflow.model.Features"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.model.Features</span></code></a> and <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures" title="slideflow.DatasetFeatures"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures</span></code></a>. The former provides an interface for calculating layer activations for a batch of images, and the latter supervises calculations across an entire dataset.</p>
<section id="batch-of-images">
<h3>Batch of images<a class="headerlink" href="#batch-of-images" title="Permalink to this heading">¶</a></h3>
<p><a class="reference internal" href="../model/#slideflow.model.Features" title="slideflow.model.Features"><code class="xref py py-class docutils literal notranslate"><span class="pre">Features</span></code></a> provides an interface for calculating layer activations and predictions on a batch of images. The following arguments are available:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">path</span></code>: Path to model, from which layer activations are calculated. Required.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">layers</span></code>: Layer(s) at which to calculate activations.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">include_preds</span></code>: Also return the final network output (predictions)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">pooling</span></code>: Apply pooling to layer activations, to reduce dimensionality to one dimension.</p></li>
</ul>
<p>If <code class="docutils literal notranslate"><span class="pre">layers</span></code> is not supplied, activations at the post-convolutional layer will be calculated by default.</p>
<p>Once initialized, the resulting object can be called on a batch of images and will return the layer activations for all images in the batch. For example, to calculate activations at the <code class="docutils literal notranslate"><span class="pre">sep_conv_3</span></code> layer of a model while looping through a dataset:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">slideflow</span> <span class="k">as</span> <span class="nn">sf</span>
<span class="n">sepconv3</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">Features</span><span class="p">(</span><span class="s1">'model/path'</span><span class="p">,</span> <span class="n">layer</span><span class="o">=</span><span class="s1">'sep_conv_3'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">img_batch</span> <span class="ow">in</span> <span class="n">dataset</span><span class="p">:</span>
<span class="n">postconv_activations</span> <span class="o">=</span> <span class="n">sepconv3</span><span class="p">(</span><span class="n">img_batch</span><span class="p">)</span>
</pre></div>
</div>
<p>If <code class="docutils literal notranslate"><span class="pre">layer</span></code> is a list of layer names, activations at each layer will be calculated and concatenated. If <code class="docutils literal notranslate"><span class="pre">include_preds</span></code> is <code class="docutils literal notranslate"><span class="pre">True</span></code>, the interface will also return the final predictions:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">sepconv3_and_preds</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">Features</span><span class="p">(</span><span class="o">...</span><span class="p">,</span> <span class="n">include_preds</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">layer_activations</span><span class="p">,</span> <span class="n">preds</span> <span class="o">=</span> <span class="n">sepconv3_and_preds</span><span class="p">(</span><span class="n">img_batch</span><span class="p">)</span>
</pre></div>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p><a class="reference internal" href="../model/#slideflow.model.Features" title="slideflow.model.Features"><code class="xref py py-class docutils literal notranslate"><span class="pre">Features</span></code></a> assumes that image batches already have any necessary preprocessing already applied, including standardization and stain normalization.</p>
</div>
<p>See the API documentation for <a class="reference internal" href="../model/#slideflow.model.Features" title="slideflow.model.Features"><code class="xref py py-class docutils literal notranslate"><span class="pre">Features</span></code></a> for more information.</p>
</section>
<section id="single-slide">
<h3>Single slide<a class="headerlink" href="#single-slide" title="Permalink to this heading">¶</a></h3>
<p>Layer activations can also be calculated across an entire slide using the same <a class="reference internal" href="../model/#slideflow.model.Features" title="slideflow.model.Features"><code class="xref py py-class docutils literal notranslate"><span class="pre">Features</span></code></a> interface. Calling the object on a <code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.WSI</span></code> object will generate a grid of activations of size <code class="docutils literal notranslate"><span class="pre">(slide.grid.shape[0],</span> <span class="pre">slide.grid.shape[1],</span> <span class="pre">num_features)</span></code>:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">slideflow</span> <span class="k">as</span> <span class="nn">sf</span>
<span class="n">slide</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">WSI</span><span class="p">(</span><span class="o">...</span><span class="p">)</span>
<span class="n">postconv</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">Features</span><span class="p">(</span><span class="s1">'/model/path'</span><span class="p">,</span> <span class="n">layers</span><span class="o">=</span><span class="s1">'postconv'</span><span class="p">)</span>
<span class="n">feature_grid</span> <span class="o">=</span> <span class="n">postconv</span><span class="p">(</span><span class="n">slide</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">feature_grid</span><span class="o">.</span><span class="n">shape</span><span class="p">)</span>
</pre></div>
</div>
<div class="sphx-glr-script-out highlight-none notranslate"><div class="highlight"><pre><span></span>(50, 45, 2048)
</pre></div>
</div>
</section>
<section id="entire-dataset">
<span id="dataset-features"></span><h3>Entire dataset<a class="headerlink" href="#entire-dataset" title="Permalink to this heading">¶</a></h3>
<p>Finally, layer activations can also be calculated for an entire dataset using <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures" title="slideflow.DatasetFeatures"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures</span></code></a>. Instancing the class supervises the calculation and caching of layer activations, which can then be used for downstream analysis. The project function <a class="reference internal" href="../project/#slideflow.Project.generate_features" title="slideflow.Project.generate_features"><code class="xref py py-func docutils literal notranslate"><span class="pre">slideflow.Project.generate_features()</span></code></a> creates and returns an instance of this class.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">dts_ftrs</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_features</span><span class="p">(</span><span class="s1">'/path/to/trained_model'</span><span class="p">)</span>
</pre></div>
</div>
<p>Alternatively, you can create an instance of this class directly:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">slideflow</span> <span class="k">as</span> <span class="nn">sf</span>
<span class="n">dataset</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">dataset</span><span class="p">(</span><span class="n">tile_px</span><span class="o">=</span><span class="mi">299</span><span class="p">,</span> <span class="n">tile_um</span><span class="o">=</span><span class="mi">302</span><span class="p">)</span>
<span class="n">dts_ftrs</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">DatasetFeatures</span><span class="p">(</span>
<span class="n">model</span><span class="o">=</span><span class="s1">'/path/to/trained_model'</span><span class="p">,</span>
<span class="n">dataset</span><span class="o">=</span><span class="n">dataset</span><span class="p">,</span>
<span class="p">)</span>
</pre></div>
</div>
<p>Tile-level feature activations for each slide can be accessed directly from <code class="docutils literal notranslate"><span class="pre">DatasetFeatures.activations</span></code>, a dict mapping slide names to numpy arrays of shape <code class="docutils literal notranslate"><span class="pre">(num_tiles,</span> <span class="pre">num_features)</span></code>. Predictions are stored in <code class="docutils literal notranslate"><span class="pre">DatasetFeatures.predictions</span></code>, a dict mapping slide names to numpy arrays of shape <code class="docutils literal notranslate"><span class="pre">(num_tiles,</span> <span class="pre">num_classes)</span></code>. Tile-level location data (coordinates from which the tiles were taken from their respective source slides) is stored in <code class="docutils literal notranslate"><span class="pre">DatasetFeatures.locations</span></code>, a dict mapping slide names to numpy arrays of shape <code class="docutils literal notranslate"><span class="pre">(num_tiles,</span> <span class="pre">2)</span></code> (<code class="docutils literal notranslate"><span class="pre">x</span></code>, <code class="docutils literal notranslate"><span class="pre">y</span></code>).</p>
<p>Activations can be exported to a Pandas DataFrame with <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures.to_df" title="slideflow.DatasetFeatures.to_df"><code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures.to_df()</span></code></a> or exported into PyTorch format with <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures.to_torch" title="slideflow.DatasetFeatures.to_torch"><code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures.to_torch()</span></code></a>. See <a class="reference internal" href="../features/#features"><span class="std std-ref">Generating Features</span></a> for more information about generating and exporting features for MIL models.</p>
<p>Read the API documentation for <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures" title="slideflow.DatasetFeatures"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures</span></code></a> for more information.</p>
</section>
</section>
<section id="mapping-activations">
<span id="slidemap"></span><h2>Mapping Activations<a class="headerlink" href="#mapping-activations" title="Permalink to this heading">¶</a></h2>
<p>Layer activations across a dataset can be dimensionality reduced with UMAP and plotted for visualization using <a class="reference internal" href="../dataset_features/#slideflow.DatasetFeatures.map_activations" title="slideflow.DatasetFeatures.map_activations"><code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.DatasetFeatures.map_activations()</span></code></a>. This function returns an instance of <a class="reference internal" href="../slidemap/#slideflow.SlideMap" title="slideflow.SlideMap"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.SlideMap</span></code></a>, a class that provides easy access to labeling and plotting.</p>
<p>The below example calculates layer activations at the neural network layer <code class="docutils literal notranslate"><span class="pre">sep_conv_3</span></code> for an entire dataset, and then reduces the activations into two dimensions for easy visualization using UMAP. Any valid <a class="reference external" href="https://umap-learn.readthedocs.io/en/latest/parameters.html">UMAP parameters</a> can be passed via keyword argument.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">dts_ftrs</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_features</span><span class="p">(</span>
<span class="n">model</span><span class="o">=</span><span class="s1">'/path/to/trained_model'</span><span class="p">,</span>
<span class="n">layers</span><span class="o">=</span><span class="s1">'sep_conv_3'</span>
<span class="p">)</span>
<span class="n">slide_map</span> <span class="o">=</span> <span class="n">dts_ftrs</span><span class="o">.</span><span class="n">map_activations</span><span class="p">(</span>
<span class="n">n_neighbors</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="c1"># UMAP parameter</span>
<span class="n">min_dist</span><span class="o">=</span><span class="mf">0.2</span> <span class="c1"># UMAP parameter</span>
<span class="p">)</span>
</pre></div>
</div>
<p>We can then plot the activations with <a class="reference internal" href="../slidemap/#slideflow.SlideMap.plot" title="slideflow.SlideMap.plot"><code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.SlideMap.plot()</span></code></a>. All keyword arguments are passed to the <a class="reference external" href="https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.scatter.html">matplotlib scatter</a> function.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">matplotlib.pyplot</span> <span class="k">as</span> <span class="nn">plt</span>
<span class="n">slide_map</span><span class="o">.</span><span class="n">plot</span><span class="p">(</span><span class="n">s</span><span class="o">=</span><span class="mi">10</span><span class="p">)</span>
<span class="n">plt</span><span class="o">.</span><span class="n">show</span><span class="p">()</span>
</pre></div>
</div>
<p>We can add labels to our plot by first passing a dictionary with slide labels to the function <a class="reference internal" href="../slidemap/#slideflow.SlideMap.label_by_slide" title="slideflow.SlideMap.label_by_slide"><code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.SlideMap.label_by_slide()</span></code></a>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># Get a dictionary mapping slide names to category labels</span>
<span class="n">dataset</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">dataset</span><span class="p">(</span><span class="n">tile_px</span><span class="o">=</span><span class="mi">299</span><span class="p">,</span> <span class="n">tile_um</span><span class="o">=</span><span class="s1">'10x'</span><span class="p">)</span>
<span class="n">labels</span><span class="p">,</span> <span class="n">unique_labels</span> <span class="o">=</span> <span class="n">dataset</span><span class="o">.</span><span class="n">labels</span><span class="p">(</span><span class="s1">'subtype'</span><span class="p">,</span> <span class="nb">format</span><span class="o">=</span><span class="s1">'name'</span><span class="p">)</span>
<span class="c1"># Assign the labels to the slide map, then plot</span>
<span class="n">slide_map</span><span class="o">.</span><span class="n">label_by_slide</span><span class="p">(</span><span class="n">labels</span><span class="p">)</span>
<span class="n">slide_map</span><span class="o">.</span><span class="n">plot</span><span class="p">()</span>
</pre></div>
</div>
<img alt="../_images/umap_example.png" src="../_images/umap_example.png" />
<div class="line-block">
<div class="line"><br /></div>
</div>
<p>Finally, we can use <code class="xref py py-meth docutils literal notranslate"><span class="pre">SlideMap.umap_transform()</span></code> to project new data into two dimensions using the previously fit UMAP.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">slideflow</span> <span class="k">as</span> <span class="nn">sf</span>
<span class="kn">import</span> <span class="nn">numpy</span> <span class="k">as</span> <span class="nn">np</span>
<span class="c1"># Create a SlideMap using layer activations reduced with UMAP</span>
<span class="n">dts_ftrs</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_features</span><span class="p">(</span>
<span class="n">model</span><span class="o">=</span><span class="s1">'/path/to/trained_model'</span><span class="p">,</span>
<span class="n">layers</span><span class="o">=</span><span class="s1">'sep_conv_3'</span>
<span class="p">)</span>
<span class="n">slide_map</span> <span class="o">=</span> <span class="n">dts_ftrs</span><span class="o">.</span><span class="n">map_activations</span><span class="p">()</span>
<span class="c1"># Load some dummy data.</span>
<span class="c1"># Second dimension must match size of activation vector.</span>
<span class="n">dummy</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">random</span><span class="o">.</span><span class="n">random</span><span class="p">((</span><span class="mi">100</span><span class="p">,</span> <span class="mi">1024</span><span class="p">))</span>
<span class="c1"># Transform the data using the already-fit UMAP.</span>
<span class="n">transformed</span> <span class="o">=</span> <span class="n">slide_map</span><span class="o">.</span><span class="n">umap_transform</span><span class="p">(</span><span class="n">dummy</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">transformed</span><span class="o">.</span><span class="n">shape</span><span class="p">)</span>
</pre></div>
</div>
<div class="sphx-glr-script-out highlight-none notranslate"><div class="highlight"><pre><span></span>(100, 2)
</pre></div>
</div>
<p>Read more about additional <a class="reference internal" href="../slidemap/#slideflow.SlideMap" title="slideflow.SlideMap"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.SlideMap</span></code></a> functions, including saving, loading, and clustering, in the linked API documentation.</p>
</section>
<section id="mosaic-maps">
<span id="mosaic-map"></span><h2>Mosaic Maps<a class="headerlink" href="#mosaic-maps" title="Permalink to this heading">¶</a></h2>
<p>Mosaic maps provide a tool for visualizing the distribution of histologic image features in a dataset through analysis of neural network layer activations. Similar to <a class="reference external" href="https://distill.pub/2019/activation-atlas/">activation atlases</a>, a mosaic map is generated by first calculating layer activations for a dataset, dimensionality reducing these activations with <a class="reference external" href="https://joss.theoj.org/papers/10.21105/joss.00861">UMAP</a>, and then overlaying corresponding images in a grid-wise fashion.</p>
<img alt="../_images/mosaic_example.png" src="../_images/mosaic_example.png" />
<div class="line-block">
<div class="line"><br /></div>
</div>
<p>In the previous sections, we reviewed how to calculate layer activations across a dataset, and then dimensionality reduce these activations into two dimensions using UMAP. <a class="reference internal" href="../mosaic/#slideflow.Mosaic" title="slideflow.Mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Mosaic</span></code></a> provides a tool for converting these activation maps into a grid of image tiles plotted according to their associated activation vectors.</p>
<section id="quickstart">
<h3>Quickstart<a class="headerlink" href="#quickstart" title="Permalink to this heading">¶</a></h3>
<p>The fastest way to build a mosaic map is using <a class="reference internal" href="../project/#slideflow.Project.generate_mosaic" title="slideflow.Project.generate_mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Project.generate_mosaic</span></code></a>, which requires a <code class="docutils literal notranslate"><span class="pre">DatasetFeatures</span></code> object as its only mandatory argument and returns an instance of <a class="reference internal" href="../mosaic/#slideflow.Mosaic" title="slideflow.Mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Mosaic</span></code></a>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">dts_ftrs</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_features</span><span class="p">(</span><span class="s1">'/path/to/trained_model'</span><span class="p">,</span> <span class="n">layers</span><span class="o">=</span><span class="s1">'postconv'</span><span class="p">)</span>
<span class="n">mosaic</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_mosaic</span><span class="p">(</span><span class="n">dts_ftrs</span><span class="p">)</span>
<span class="n">mosaic</span><span class="o">.</span><span class="n">save</span><span class="p">(</span><span class="s1">'mosaic.png'</span><span class="p">)</span>
</pre></div>
</div>
<p>When created with this interface, the underlying <a class="reference internal" href="../slidemap/#slideflow.SlideMap" title="slideflow.SlideMap"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.SlideMap</span></code></a> object used to create the mosaic map is accessible via <code class="docutils literal notranslate"><span class="pre">slideflow.Mosaic.slide_map</span></code>. You could, for example, use <a class="reference internal" href="../slidemap/#slideflow.SlideMap.save" title="slideflow.SlideMap.save"><code class="xref py py-func docutils literal notranslate"><span class="pre">slideflow.SlideMap.save()</span></code></a> to save the UMAP plot:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">mosiac</span><span class="o">.</span><span class="n">slide_map</span><span class="o">.</span><span class="n">save</span><span class="p">(</span><span class="s1">'umap.png'</span><span class="p">)</span>
</pre></div>
</div>
</section>
<section id="from-a-slidemap">
<h3>From a SlideMap<a class="headerlink" href="#from-a-slidemap" title="Permalink to this heading">¶</a></h3>
<p>Any <code class="docutils literal notranslate"><span class="pre">SlideMap</span></code> can be converted to a mosaic map with <code class="xref py py-meth docutils literal notranslate"><span class="pre">slideflow.SlideMap.generate_mosaic()</span></code>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">ftrs</span> <span class="o">=</span> <span class="n">P</span><span class="o">.</span><span class="n">generate_features</span><span class="p">(</span><span class="s1">'/path/to/model'</span><span class="p">)</span>
<span class="n">slide_map</span> <span class="o">=</span> <span class="n">ftrs</span><span class="o">.</span><span class="n">map_activations</span><span class="p">()</span>
<span class="n">mosaic</span> <span class="o">=</span> <span class="n">slide_map</span><span class="o">.</span><span class="n">generate_mosaic</span><span class="p">()</span>
<span class="n">mosaic</span><span class="o">.</span><span class="n">save</span><span class="p">(</span><span class="s1">'mosaic.png'</span><span class="p">)</span>
</pre></div>
</div>
</section>
<section id="manual-creation">
<h3>Manual creation<a class="headerlink" href="#manual-creation" title="Permalink to this heading">¶</a></h3>
<p>Mosaic maps can be flexibly created with <a class="reference internal" href="../mosaic/#slideflow.Mosaic" title="slideflow.Mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Mosaic</span></code></a>, requiring two components: a set of images and corresponding coordinates. Images and coordinates can either be manually provided, or the mosaic can dynamically read images from TFRecords (as is done with <code class="xref py py-meth docutils literal notranslate"><span class="pre">Project.generate_mosaic()</span></code>).</p>
<p>The first argument of <a class="reference internal" href="../mosaic/#slideflow.Mosaic" title="slideflow.Mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Mosaic</span></code></a> provides the images, and may be either of the following:</p>
<ul class="simple">
<li><p>A list or array of images (np.ndarray, HxWxC)</p></li>
<li><p>A list of tuples, containing <code class="docutils literal notranslate"><span class="pre">(slide_name,</span> <span class="pre">tfrecord_index)</span></code></p></li>
</ul>
<p>The second argument provides the coordinates:</p>
<ul class="simple">
<li><p>A list or array of (x, y) coordinates for each image</p></li>
</ul>
<p>For example, to create a mosaic map from a list of images and coordinates:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># Example data (images are HxWxC, np.ndarray)</span>
<span class="n">images</span> <span class="o">=</span> <span class="p">[</span><span class="n">np</span><span class="o">.</span><span class="n">ndarray</span><span class="p">(</span><span class="o">...</span><span class="p">),</span> <span class="o">...</span><span class="p">]</span>
<span class="n">coords</span> <span class="o">=</span> <span class="p">[(</span><span class="mf">0.2</span><span class="p">,</span> <span class="mf">0.9</span><span class="p">),</span> <span class="o">...</span><span class="p">]</span>
<span class="c1"># Generate the mosaic</span>
<span class="n">mosaic</span> <span class="o">=</span> <span class="n">Mosaic</span><span class="p">(</span><span class="n">images</span><span class="p">,</span> <span class="n">coordinates</span><span class="p">)</span>
<span class="n">mosaic</span><span class="o">.</span><span class="n">plot</span><span class="p">()</span>
</pre></div>
</div>
<p>You can also generate a mosaic map where the images are tuples of <cite>(tfrecord, tfrecord_index)</cite>. In this case, the mosaic map will dynamically read images from TFRecords during plotting.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># Example data</span>
<span class="n">tfrecords</span> <span class="o">=</span> <span class="p">[</span><span class="s1">'/path/to/tfrecord`.tfrecords'</span><span class="p">,</span> <span class="o">...</span><span class="p">]</span>
<span class="n">idx</span> <span class="o">=</span> <span class="p">[</span><span class="mi">253</span><span class="p">,</span> <span class="mi">112</span><span class="p">,</span> <span class="o">...</span><span class="p">]</span>
<span class="n">coords</span> <span class="o">=</span> <span class="p">[(</span><span class="mf">0.2</span><span class="p">,</span> <span class="mf">0.9</span><span class="p">),</span> <span class="o">...</span><span class="p">]</span>
<span class="c1"># Generate mosaic map</span>
<span class="n">mosaic</span> <span class="o">=</span> <span class="n">sf</span><span class="o">.</span><span class="n">Mosaic</span><span class="p">(</span>
<span class="n">images</span><span class="o">=</span><span class="p">[(</span><span class="n">tfr</span><span class="p">,</span> <span class="n">idx</span><span class="p">)</span> <span class="k">for</span> <span class="n">tfr</span><span class="p">,</span> <span class="n">idx</span> <span class="ow">in</span> <span class="nb">zip</span><span class="p">(</span><span class="n">tfrecords</span><span class="p">,</span> <span class="n">idx</span><span class="p">)],</span>
<span class="n">coords</span><span class="o">=</span><span class="n">coords</span>
<span class="p">)</span>
</pre></div>
</div>
<p>There are several additional arguments that can be used to customize the mosaic map plotting. Read the linked API documentation for <a class="reference internal" href="../mosaic/#slideflow.Mosaic" title="slideflow.Mosaic"><code class="xref py py-class docutils literal notranslate"><span class="pre">slideflow.Mosaic</span></code></a> for more information.</p>
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<ul>
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<li><a class="reference internal" href="#calculating-layer-activations">Calculating Layer Activations</a><ul>
<li><a class="reference internal" href="#batch-of-images">Batch of images</a></li>
<li><a class="reference internal" href="#single-slide">Single slide</a></li>
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