 
 var parameters = MNISTParameters()
 // Start training.
-train(&parameters, iterationCount: 20)
+train(&parameters, epochCount: 20)

    var loss = Float.infinity

    // Training loop.
    print("Begin training for \(iterationCount) iterations.")

    for _ in 0...iterationCount {
        // Forward pass.
        let z1 = images • parameters.w1 + parameters.b1
        let h1 = sigmoid(z1)

    var b2 = Tensor<Float>(zeros: [1, 10])
}

/// Train a MNIST classifier for the specified number of epochs.
func train(_ parameters: inout MNISTParameters, epochCount: Int) {
    // Get script path. This is necessary for MNIST.swift to work when invoked
    // from any directory.
    let currentScriptPath = URL(fileURLWithPath: #file)
