Adding Weights Files

Our first model did not need any weights files. We just created weights and bias at runtime.

But real-world models typically need weights files, and maybe some other supporting files.

We recommend, for easy deployments, you upload those files. In many instances, you will use a site like 🤗 Hugging Face.

We also recommend to add a weights.bzl file to your project root directory, so you don't "pollute" your build file with long URLs and SHAs:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_file")

def _weights_impl(mctx):
    http_file(
        name = "com_github_zml_cdn_mnist",
        downloaded_file_path = "mnist.pt",
        sha256 = "d8a25252e28915e147720c19223721f0f53e3317493727ca754a2dd672450ba9",
        url = "https://github.com/ggerganov/ggml/raw/18703ad600cc68dbdb04d57434c876989a841d12/examples/mnist/models/mnist/mnist_model.state_dict",
    )

    http_file(
        name = "com_github_zml_cdn_mnist_data",
        downloaded_file_path = "mnist.ylc",
        sha256 = "0fa7898d509279e482958e8ce81c8e77db3f2f8254e26661ceb7762c4d494ce7",
        url = "https://github.com/ggerganov/ggml/raw/18703ad600cc68dbdb04d57434c876989a841d12/examples/mnist/models/mnist/t10k-images.idx3-ubyte",
    )

    return mctx.extension_metadata(
        reproducible = True,
        root_module_direct_deps = "all",
        root_module_direct_dev_deps = [],
    )

weights = module_extension(
    implementation = _weights_impl,
)

The above weights.bzl shows how we load files for MNIST:

• mnist.pt (model weights)
• mnist.ylc (dataset for picking sample images)

Then, in your BUILD.bazel, you can refer to the files you defined above, in the following way:

zig_cc_binary(
    name = "mnist",
    args = [
        "$(location @com_github_zml_cdn_mnist//file)",
        "$(location @com_github_zml_cdn_mnist_data//file)",
    ],
    data = [
        "@com_github_zml_cdn_mnist//file",
        "@com_github_zml_cdn_mnist_data//file",
    ],
    main = "mnist.zig",
    deps = [
        "//async",
        "//zml",
    ],
)

See how:

• we use data = [ ... ] to reference the files in weights.bzl
• we use args = [ ... ] to pass the files as command-line arguments to the MNIST executable at runtime, automatically.