4 ms·

My numerical analysis professor once told the class a story about how he used the finite element method to solve stresses on pieces of metal for the soviet spac

My numerical analysis professor once told the class a story about how he used the finite element method to solve stresses on pieces of metal for the soviet space program. Computers were too expensive, so they did it by hand. They cleared a university classroom of all the chairs and desks, and rolled out pieces of paper to cover the floor. The team took their shoes off proceeded from one corner of the room to the other. If you found that someone had made a mistake, you had a record available to find it, and you could simply rip up the paper at the point where the mistake was made and roll out fresh paper to take its place. Apparently a triangle took a few days. SolidWorks does the same math today.

hydrogen7800 4y ago
I once read or heard a similar anecdote about Ludwig Prandtl who set up computation method using a room full of people each doing one step of a calculation. I recall it describing a finite element method, but that would predate the origin of FEM in this article by a few decades. Maybe it was just some numerical method.
- pclmulqdq 4y ago
  I assume it would be a finite differences calculation, which is also very easy to parallelize/vectorize. They solve the same class of problems, but calculations with finite differences don't always converge the way that finite elements do.
  - marmetio 4y ago
    That's correct, it was finite difference methods. There are many variations with different properties such as whether they'll definitely converge or not.
- perilunar 4y ago
  Huh? Theres's a long history of doing this — 'computers' were people long before they are machines.
  - adrian_b 4y ago
    Yes, indeed. My father's first job was as a "computer" at an astronomical observatory (in the fifties of the 20th century, when vacuum tube computers had just started to appear, but they had astronomical prices, so they were out of reach for an astronomical observatory).
  - hydrogen7800 4y ago
    I'm aware of human "computers" but my recollection was that in the case of Prandtl, it was an application FEM. I did not know FEM wasn't developed at that time, as this article shows, so it must have been something else.
    - adrian_b 4y ago
      As a poster above has already said, it might have been a finite difference method, because they solve the same problems. Unlike FEM, finite difference methods have been used right since the origins of differential and integral calculus, with Newton and Leibniz. There are also precursors of the modern FEM, like the Ritz or Galerkin methods, which could have been used by Prandtl.

hydrogen7800 4y ago

I once read or heard a similar anecdote about Ludwig Prandtl who set up computation method using a room full of people each doing one step of a calculation. I recall it describing a finite element method, but that would predate the origin of FEM in this article by a few decades. Maybe it was just some numerical method.

pclmulqdq 4y ago
I assume it would be a finite differences calculation, which is also very easy to parallelize/vectorize. They solve the same class of problems, but calculations with finite differences don't always converge the way that finite elements do.
- marmetio 4y ago
  That's correct, it was finite difference methods. There are many variations with different properties such as whether they'll definitely converge or not.
perilunar 4y ago
Huh? Theres's a long history of doing this — 'computers' were people long before they are machines.
- adrian_b 4y ago
  Yes, indeed. My father's first job was as a "computer" at an astronomical observatory (in the fifties of the 20th century, when vacuum tube computers had just started to appear, but they had astronomical prices, so they were out of reach for an astronomical observatory).
- hydrogen7800 4y ago
  I'm aware of human "computers" but my recollection was that in the case of Prandtl, it was an application FEM. I did not know FEM wasn't developed at that time, as this article shows, so it must have been something else.
  - adrian_b 4y ago
    As a poster above has already said, it might have been a finite difference method, because they solve the same problems. Unlike FEM, finite difference methods have been used right since the origins of differential and integral calculus, with Newton and Leibniz. There are also precursors of the modern FEM, like the Ritz or Galerkin methods, which could have been used by Prandtl.