• Fear of large codes
• Concern that software development should be more valued as an integral part of research

More broadly, I would argue these concerns still affect the community involved in scientific research as a whole. Why? Let me elaborate on them.

Fear of large codes

In general, a graduate research program is aimed at exploring a very specific scientific problem or question. What distinguishes graduate work from a lower-level degree is the level of detail expected when exploring the topic -- a Ph.D. program is intended to produce experts. In the STEM area, one frequently used approach to tackle research problems is through a "proof-of-concept" (POC), involving a simplified problem that has the advantage of being tractable, while still maintaining features of the full problem. Note that a POC approach is not always possible, as simplifications are not always warranted, and some problems must be addressed head-on. In the field of computational science, a POC is typically a small, self-contained code written from scratch, usually using a language known to the student, often a "productivity-oriented" language such as Python or Matlab. With this approach, the student has full control of the code, can work autonomously, and retains ample freedom to change the implementation as needed. The feeling of being in this kind of situation is one to remember: you feel in control, knowing all the details, the various shortcuts taken in this short program, and any modification is relatively inexpensive to do since the code is small enough that writing and rewriting it is a feasible effort. As one of my colleagues used to say: "I love when I can prototype ideas and explore them with a Python script of a couple hundred lines!"

However, such a "sandbox reality" has a limited lifetime. At some point, the POC will no longer be sufficient to make the deep progress expected, and problems of greater complexity need to be studied. This circumstance is typically the turning point when larger-scale software comes into the picture, and it also marks the time when many graduate students face the "fear of large codes." A large code is diametrically opposed to the POC experience: an individual now has only partial control; has to work in a team comprising multiple people; has to systematically deal with version control, where even small changes require more work; other developers might change the code "under your feet" requiring the individual to constantly update; developers who wrote parts of the code may have left and nobody remaining knows the inner workings of some functions; and, finally, the individual often has to dig deep into the code to understand it because the code lacks adequate documentation. With all these factors and unknowns playing a role, the fear of facing such a seemingly hard task grows, and with it, the pressure to deliver.

It is natural to ask at this point: why is this fear of large codes so common? After all, not all students are like the one mentioned at the beginning of this article, praised for their "lack of fear" of getting their hands dirty with large codes. What if there were a way for most students to work on large codes without necessarily needing years of development experience and, most importantly, without being afraid of them? You may think this a utopian view, but I would argue that such a reality could exist. Imagine a code (started as a small project, but on its way to becoming a large one) developed from the beginning with accessibility and sustainability in mind: the design is modular and flexible (e.g., in object-oriented programming (OOP) the SOLID principles are meticulously met), documentation is complete, and the test suite is well developed. If this were the case, I believe that any person with even a minimum set of skills should be able to contribute -- such a code need not be feared, but rather appreciated and liked by users who are comfortable using it in their learning and research. However, there is a caveat, in that more often than not, the time scale of developing a "pristine" code conflicts with funding and research timelines, which brings me to the following point.

Concern that software development should be more valued as an integral part of research

Despite software's fundamental role in computational science, some research efforts are still carried out by treating software just as a means to an end. This circumstance is particularly common in projects driven by graduate students. For example, it is common to see codes developed only for a paper, and then the codes are forgotten, or research proposals are written without explicitly mentioning software development as a critical deliverable. I would argue that this approach must change for software to be sustainable, accessible, and maintainable. Software development should be a first-class entity in a research effort focusing on computational science. Reconciling the need for high-quality software with the actual research questions to address and balancing it all out, budget-wise, is hard. But, for the sake of the argument, what could happen if a non-trivial part of a research budget were explicitly dedicated to the software development required? Broadly speaking, I would argue that this approach could benefit the scientific community as a whole. First, this approach would allow graduate students and junior researchers to learn many skills along the way, e.g. team development, testing, and software quality, which would later prove critical for the job market---after all, many of them are the computational scientists of the future. Second, developing solid and robust software would decrease the chances of doing something incorrectly and, therefore, increase the trustworthiness of the results, which is critical for scientific reproducibility. Finally, any research code developed from the ground up with good practices would less likely be forgotten and more likely become the starting point for a production code (or a stepping stone for other work).

What if AI models take over?

Some people believe that the rise of AI and large language models (LLMs) will change the way we write and understand software. In fact, some experts in the field of programming believe that humans writing software and the corresponding documentation, and the whole idea of software maintainability will eventually become obsolete. Why? Because, assuming a powerful enough AI/LLM system were available, this system would write the software and its documentation in a matter of minutes. Furthermore, there would not be a need to maintain the software, as the cost of constantly re-writing it from scratch and replacing it would be small -- negligible compared to the cost of humans developing software. At this point, you might wonder: if all of this is coming in the (near) future, does it mean everything said above fails to hold? Will the fear of large codes disappear since AI systems can help us understand code, no matter how complex it is, and contribute to it without the need to have deep software skills? Will it still be necessary to form good software engineers and pick up these skills early on?

A fully articulated answer to these questions deserves a separate post, but I dare express a few main points. First, learning and knowing good software practices is still needed to read and understand other peoples' (or AIs') codes. This skill is especially important to assess security and identify weaknesses and vulnerabilities. For example, what seems a vulnerability to the human eye might be a safe call by an AI. Second, I fully agree that -- at the time of this article -- AI tools (e.g., GitHub copilot or LLMs) can be very useful to assist with what is referred to as boilerplate code, refactoring efforts, API documentation, plots, etc. Personally, I believe such a use case is valuable because, if seen as a starting point for individuals to build on, boilerplate code can save a lot of time. A great example of this is a recent CppCon23 keynote, which I recommend highly. However, I am skeptical (for now) that AI will replace the creative innovation and design skills of good software developers, especially those working in a team. For the sake of the argument, let's assume I am wrong: we have an AI system capable of tackling and solving complex architectural and/or design decisions equally well (or better) than humans. I do not look forward to a future where we avoid critical thinking, learning, and problem solving, and just delegate that too.

Author bio

Francesco Rizzi is CTO and principal scientist at NexGen Analytics. Broadly speaking, he works in the field of scientific computing---which he is really passionate about. He is currently engaged in multiple projects, from performance portability and linear algebra to generic programming, model reduction of large-scale applications, and uncertainty quantification. Prior to NexGen, he was a senior technical staff member in Scalable Modeling & Analysis Systems at Sandia National Labs. He holds an M.Sc. in Computational Physics from the University of Udine (Italy), and an M.Sc./Ph.D. in Mechanical Engineering from The Johns Hopkins University.