A colleague of mine talked about a calculation he had pushed to a new height of precision. He had a tool. A computer program from the 1980's.
Particle physicists use a lot of long equations in their work. They draw thousands of pictures called Feynman diagrams that depict possible collision outcomes in order to find signs of new elementary particles. Adding these formulas with computers is a challenge. The particle physics rules we learn in school are not very efficient.
The programs aim to handle these tasks. FORM is the only program that has solved the biggest equations in the world for 33 years.
FORM is a part of the infrastructure of particle physics that is needed for the hardest calculations. As with many essential pieces of digital infrastructure, FORM's maintenance is done by one person. At 73, Vermaseren has stopped working on FORM. The incentive structure of academia has made no successor emerge. Particle physics may be forced to slow down if the situation isn't changed.
When the role of computers was changing rapidly in the 1980's, FORM started. Schoonschip was released as a special chip that you plugged into the Atari computer. The program could be downloaded by universities all over the world. He used FORTRAN to program it. FORM was a reference to that. The programming language he used was called C. His software came out in 1989. The number of institutions that had downloaded it kept increasing.
Every few days, a particle physics paper that cites FORM has been published. The majority of the high-precision results that our group obtained in the past 20 years were based on FORM code.
A procedure for rearranging equations to have as few multiplications and additions as possible was one of the reasons FORM was popular. The most powerful advantage of FORM is its ability to handle memory.
Humans and computers have two different types of memory, main and external. It is easy to get your main memory on the fly, but limited in size. Hard disks and solid-state drives are slower than external memory devices. If you want to solve a long equation, you need to store it in main memory.
Both types of memory were limited in the '80s. FORM was built in a time when there wasn't a lot of memory or disk space. The equations were too long for main memory to process. If you wanted to calculate one, your operating system had to treat your hard disk like main memory too.
FORM uses its own techniques. Each term is assigned a fixed amount of space on the hard disk by the program. This technique makes it easier for the software to keep track of the equation's location. It's easy to bring those pieces back to main memory when you need them.
From 128 kilobytes of ram in the Atari 130XE in 1985 to 128 gigabyte of ram in my souped up desktop, memory has grown a millionfold. The tricks that were developed remain important. Their need for precision and the length of their equations increases as they search for evidence of new particles in large amounts of data.
There is always a physics problem that can push these things beyond the size of the memory.
Every two years the computer capabilities double. There are forms of growth that are quicker than the others. It's possible to write three letters in all possible orders. There are three options for the first, second and third letters. The problem scales as a factorial and grows much faster than exponential growth. Factorials show up when you try to count combinations of things, such as all the different diagrams you can draw for colliding particles. The growth of computing power is slower than the growth of particle physics calculations.
The effort to develop FORM is often overlooked. He had a permanent position at the National Institute for Subatomic Physics in the Netherlands and a boss who appreciated his work. It's difficult to get such luck. Laporta has spent most of his career without funding for students or equipment. Scientists who work on critical infrastructure are more likely to be passed over for hiring or tenure than other scientists.
People who spend a lot of time on computers don't get tenure jobs in physics.
It is more prestigious to produce physical results than to use tools.
While a few younger physicists work on FORM occasionally, they need to devote most of their time to other research in order to have a good career. Most of the responsibility for developing FORM is left to the man who is now retired.
FORM will become less and less usable if ongoing development is not continued. Older users will stick with it, but younger researchers will use alternative programs that are more user friendly, but orders of magnitude slower. Physicists will decide that certain problems are too difficult to deal with. Only a few people are able to work on the hardest calculations.
A summit of FORM users is going to be held in April. How to keep FORM alive, how to maintain and extend it, and how to show a new generation of students how much it can do will be discussed. They may be able to preserve one of the most powerful tools in physics.
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