     XCTAssertEqual(sqrt((patch - recon).squared().mean()).scalar!, 10.049659587270698, accuracy: 1e-5)
   }
 
+  /// Test whether we can actually track a bee with our PPCATrackingFactor
   func testPPCATracking() {
     let frames = BeeFrames(sequenceName: "seq4")!
     let obbs = beeOrientedBoundingBoxes(sequenceName: "seq4")!

import PenguinStructures

final class BeePPCATests: XCTestCase {
  func testPPCA() {
    let frames = BeeFrames(sequenceName: "seq4")!
    let obbs = beeOrientedBoundingBoxes(sequenceName: "seq4")!

    let stacked_bw = Tensor(stacking: images_bw)
    var ppca = PPCA(latentSize: 5)
    ppca.train(images: stacked_bw)
    
    var fg = FactorGraph()
    var v = VariableAssignments()
