feat: adding pip example (#64)

Author: finn-qarik

projects/bzl7/MODULE.bazel

@@ -93,3 +93,11 @@ use_repo(
     "python_3_12",
     "python_versions",
 )
+
+pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
+pip.parse(
+    hub_name = "pip_example_3_12",
+    python_version = "3.12",
+    requirements_lock = "@bzl7//python/pip:requirements_lock.txt",
+)
+use_repo(pip, "pip_example_3_12")

projects/bzl7/python/pip/BUILD.bazel

@@ -0,0 +1,20 @@
+load("@aspect_rules_py//py:defs.bzl", "py_binary")
+load("@pip_example_3_12//:requirements.bzl", "requirement")
+load("@rules_python//python:pip.bzl", "compile_pip_requirements")
+
+compile_pip_requirements(
+    name = "python_requirements",
+    requirements_in = ":requirements.txt",
+    requirements_txt = ":requirements_lock.txt",
+    tags = ["manual"],
+)
+
+py_binary(
+    name = "main",
+    srcs = ["main.py"],
+    visibility = ["//visibility:public"],
+    deps = [
+        requirement("matplotlib"),
+        requirement("numpy"),
+    ],
+)

projects/bzl7/python/pip/README.md

@@ -0,0 +1,5 @@
+# Updating Requirements
+To update the requirements, execute the following:
+```
+bazel run //python/pip:python_requirements.update
+```

projects/bzl7/python/pip/main.py

@@ -0,0 +1,45 @@
+import matplotlib.pyplot as plt
+import numpy as np
+import warnings
+
+from pathlib import Path
+
+def compute_mandelbrot(max_iter: int, threshold: float, width: int, height: int) -> np.ndarray:
+    """
+    Computes the Mandelbrot set over a specified grid.
+
+    Parameters:
+    - max_iter: maximum number of iterations per point
+    - threshold: escape threshold
+    - width: number of points along the x-axis
+    - height: number of points along the y-axis
+    """
+    x = np.linspace(-2, 1, width)
+    y = np.linspace(-1.5, 1.5, height)
+    c = x[:, None] + 1j * y[None, :]
+
+    z = c.copy()
+
+    # Suppress any overflow.
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore")
+        for _ in range(max_iter):
+            z = z**2 + c
+        mandelbrot_set = (np.abs(z) < threshold)
+
+    return mandelbrot_set
+
+if __name__ == '__main__':
+    MAX_ITER = 50
+    THRESHOLD = 50.0
+    WIDTH = 600
+    HEIGHT = 400
+
+    mandelbrot_set = compute_mandelbrot(MAX_ITER, THRESHOLD, WIDTH, HEIGHT)
+
+    plt.imshow(mandelbrot_set.T, extent=[-2, 1, -1.5, 1.5])
+
+    # Save the file and print out where it was located.
+    file_path = Path('example.png')
+    plt.savefig(file_path)
+    print("File created at:\n\t{}".format(file_path.resolve()))

projects/bzl7/python/pip/requirements.txt

@@ -0,0 +1,2 @@
+matplotlib
+numpy