Monday, February 13, 2023

A conversation with OpenAI's ChatGPT

I'm a bit late to the party when it comes to trying out ChatGPT. After seeing a somewhat provocative tweet on the subject of ChatGPT's effect on a programmer's productivity which basically claimed "use it and get 10 times faster, or don't and be pushed out of a job by the programmers who do", I decided I had to give it a go.

I have a number of concerns regarding the use of ChatGPT to boost one's productivity. Such as, if it's really valuable as a tool, and only the top five or so most popular languages are supported, is it going to kill less popular languages such as F#? A commonly cited obstacle to adoption is that it suffers from "weaker tooling" than e.g. C#. Also how valuable really is ChatGPT?

I asked ChatGPT to explain the following few but non-trivial lines:

    let rec private isHeap cmp (heap : Heap<'a>) idx =
        let count = heap.count
        if idx >= count then true
            let left = 2 * idx + 1
            let right = 2 * idx + 2
            (left >= count || cmp (heap.arr.[idx], heap.arr.[left]) && isHeap cmp heap left) &&
            (right >= count || cmp (heap.arr.[idx], heap.arr.[right]) && isHeap cmp heap right)

 Here is what the AI had to say:

This is a recursive function in F# that checks whether a given data structure is a valid heap or not. The function takes in two arguments: cmp, which is a comparison function that returns a Boolean value indicating whether the first argument is less than or equal to the second argument; and heap, which is a generic data structure of type Heap<'a>, where 'a is a type parameter representing the type of the elements in the heap. The third argument idx is the index of the current node being evaluated in the heap.

The function starts by checking if the current index is greater than or equal to the count of elements in the heap, and if it is, it returns true, which indicates that the rest of the heap is valid.

If the current index is less than the count of elements, then the function calculates the indices of the left and right children of the current node and evaluates the following conditions:

  1. If the left child index is greater than or equal to the count, then the left child does not exist and the condition is true by default.

  2. If the left child exists, then the function checks if the comparison of the current node and the left child using the cmp function is true, and if it is, it recursively calls the isHeap function on the left child. If the comparison is false, the function returns false.

  3. The same process is repeated for the right child, with the only difference being that the index of the right child is used instead of the left child.

The function returns true if both conditions for the left and right children are true, which indicates that the current node and its children form a valid heap.

I was impressed it managed to recognize that cmp is a comparison function, and also recognized the algorithm as a whole. It also managed to recognize the purpose of the generic type parameter 'a. To verify that it really "understood" what we were talking about, I then asked where was the minimum element located in such a heap.


In a binary heap, the minimum element is always located at the root node, which has an index of 0 in an array representation of the heap. In this code, the root node is represented by the element at index idx in the array heap.arr where heap is the Heap<'a> data structure passed as an argument to the isHeap function.


Correct again. But a bit unspecific, maybe. Then I got curious if it could find a bug. Over the years, I discovered and fixed a couple. My confidence in my code there isn't very high.

Yes, there is a bug in the code you submitted. The comparison function cmp is used to compare the values of two elements in the heap and determine their order. However, in a binary heap, the order of the elements is defined by a specific property such as the minimum value, maximum value, or the order of the elements in the original array. The code only checks that the parent node is less than or equal to its children, which is not necessarily the correct comparison for all binary heap data structures.

For example, if the comparison function cmp is checking for a min-heap, then the comparison should be cmp (heap.arr.[left], heap.arr.[idx]) and cmp (heap.arr.[right], heap.arr.[idx]) instead of cmp (heap.arr.[idx], heap.arr.[left]) and cmp (heap.arr.[idx], heap.arr.[right]), respectively.


That got me really scratching my head, because I could not find that I should follow its advice. I ask it if it was sure

I apologize, my previous statement was incorrect. The code as written is actually checking if the parent node is less than or equal to its children, which is the correct way to validate a min-heap. The condition cmp (heap.arr.[idx], heap.arr.[left]) checks if the parent node is less than or equal to its left child, and the condition cmp (heap.arr.[idx], heap.arr.[right]) checks if the parent node is less than or equal to its right child. If these conditions are both true for each node in the heap, then the heap is considered to be a valid min-heap.

Ah, that's better. But why did it give me an incorrect bug suggestion with such confidence? I asked it and got a rather generic answer about language models.

ChatGPT: As an AI language model, I sometimes make mistakes in my responses, even though I have been trained on a large corpus of text.

Me: Is it correct to say that me asking you if there was a bug lead you to answer yes, because many conversations about bugs start that way?

ChatGPT: Yes, that is a possibility. As an AI language model, I am trained to recognize patterns in language and respond based on those patterns, but I don't have the ability to understand the context of a conversation or the intention of the user. In this case, my response was influenced by the common pattern of asking if there is a bug in code, and I made an assumption that the code provided had a bug. This highlights the importance of providing clear and concise information when communicating with an AI language model, as well as the limitations of AI technology in understanding the nuances of human language.

But even that answer makes me wonder if ChatGPT isn't just guessing what "I want to hear" and delivering that.

My initial conclusion is that ChatGPT may indeed be incredibly useful as a learning tool, and as an assistant as well. I've noticed I've been putting off some hobby projects because of my unwillingness to learn new APIs and tools during my free time, but perhaps ChatGPT could help me with that.