Fix grammar and add Wikipedia links to jax_intro.md (#445)

- Fix spelling: 'parallize' → 'parallelize'
- Fix grammar: 'target JAX' → 'targets JAX'
- Fix grammar: remove extra 'is' in 'JAX is as a drop-in'
- Fix grammar: add missing 'is' in 'full control of random state'
- Add Wikipedia links for NumPy, SciPy, automatic differentiation, functional programming, pure functions, deterministic, and side effects
- Add link to JAX scipy documentation
- Add cross-reference link to Numba exercise using {ref}

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <[email protected]>

Author: jstac

lectures/jax_intro.md

@@ -15,15 +15,15 @@ kernelspec:
 
 This lecture provides a short introduction to [Google JAX](https://github.com/jax-ml/jax).
 
-JAX is a high-performance scientific computing library that provides 
+JAX is a high-performance scientific computing library that provides
 
-* a NumPy-like interface that can automatically parallize across CPUs and GPUs,
+* a [NumPy](https://en.wikipedia.org/wiki/NumPy)-like interface that can automatically parallelize across CPUs and GPUs,
 * a just-in-time compiler for accelerating a large range of numerical
   operations, and
-* automatic differentiation.
+* [automatic differentiation](https://en.wikipedia.org/wiki/Automatic_differentiation).
 
-Increasingly, JAX also maintains and provides more specialized scientific
-computing routines, such as those originally found in SciPy.
+Increasingly, JAX also maintains and provides [more specialized scientific
+computing routines](https://docs.jax.dev/en/latest/jax.scipy.html), such as those originally found in [SciPy](https://en.wikipedia.org/wiki/SciPy).
 
 In addition to what's in Anaconda, this lecture will need the following libraries:
 
@@ -36,7 +36,7 @@ In addition to what's in Anaconda, this lecture will need the following librarie
 ```{admonition} GPU
 :class: warning
 
-This lecture is accelerated via [hardware](status:machine-details) that has access to a GPU and target JAX for GPU programming.
+This lecture is accelerated via [hardware](status:machine-details) that has access to a GPU and targets JAX for GPU programming.
 
 Free GPUs are available on Google Colab.
 To use this option, please click on the play icon top right, select Colab, and set the runtime environment to include a GPU.
@@ -50,7 +50,7 @@ If you would like to install JAX running on the `cpu` only you can use `pip inst
 One of the attractive features of JAX is that, whenever possible, its array
 processing operations conform to the NumPy API.
 
-This means that, in many cases, we can use JAX is as a drop-in NumPy replacement.
+This means that, in many cases, we can use JAX as a drop-in NumPy replacement.
 
 Let's look at the similarities and differences between JAX and NumPy.
 
@@ -199,7 +199,7 @@ a, a_new
 ```
 
 The designers of JAX chose to make arrays immutable because JAX uses a
-*functional programming style*.
+[functional programming](https://en.wikipedia.org/wiki/Functional_programming) style.
 
 This design choice has important implications, which we explore next!
 
@@ -241,19 +241,19 @@ In other words, JAX assumes a functional programming style.
 
 The major implication is that JAX functions should be pure.
 
-**Pure functions** have the following characteristics:
+[Pure functions](https://en.wikipedia.org/wiki/Pure_function) have the following characteristics:
 
 1. *Deterministic*
 2. *No side effects*
 
-**Deterministic** means
+[Deterministic](https://en.wikipedia.org/wiki/Deterministic_algorithm) means
 
 *  Same input $\implies$ same output
 *  Outputs do not depend on global state
 
 In particular, pure functions will always return the same result if invoked with the same inputs.
 
-**No side effects** means that the function
+[No side effects](https://en.wikipedia.org/wiki/Side_effect_(computer_science)) means that the function
 
 * Won't change global state
 * Won't modify data passed to the function (immutable data)
@@ -307,7 +307,7 @@ At first you might find the syntax rather verbose.
 But you will soon realize that the syntax and semantics are necessary in order
 to maintain the functional programming style we just discussed.
 
-Moreover, full control of random state 
+Moreover, full control of random state is
 essential for parallel programming, such as when we want to run independent experiments along multiple threads.
 
 
@@ -793,8 +793,8 @@ We defer further exploration of automatic differentiation with JAX until {doc}`j
 :label: jax_intro_ex2
 ```
 
-In the Exercise section of {doc}`our lecture on Numba <numba>`, we used Monte
-Carlo to price a European call option.
+In the Exercise section of {doc}`our lecture on Numba <numba>`, we {ref}`used Monte
+Carlo to price a European call option <numba_ex4>`.
 
 The code was accelerated by Numba-based multithreading.