6 ms·

I'm skeptical that students given a doctored slide rule would fare any better in a similar study. There's nothing inherent to a slide rule that gives you a bett

I'm skeptical that students given a doctored slide rule would fare any better in a similar study. There's nothing inherent to a slide rule that gives you a better sense for what the result should be. You do have to keep track of order of magnitude, but that's only going to marginally help you if we're talking about factor of 2 errors.

WalterBright 4y ago
A slide rule has the advantage in that you can see it working and how it works. A calculator has no such feedback.
- Ancapistani 4y ago
  > A calculator has no such feedback. That's an interesting thought. There's no reason a calculator has to output only a number - with the computing power and displays at our disposal today, we could easily draw and/or animate a virtual slide rule. A virtual slide rule probably wouldn't be the best option, though. It's just a visual metaphor for how the values in the calculation relate to one another, and it's one that's only going to be useful for someone who has learned to use a slide rule. I wonder if there might be an effective, generic way to present calculations visually in a way that requires little or no training to understand. Has anyone done this?
  - operator-name 4y ago
    I think it's not about the final output, but rather how the output changes with the input. Calculators are a terrible tool for this. If the model can be ran at the rate of frames per second, sliders or other non precise inputs are good for this.
    - monkpit 4y ago
      What about graphing calculators? Seeing a graph of solutions (and how the output varies with the input) can give you an intuitive reaction of whether it’s in the right ballpark or not.
    - 8note 4y ago
      A calculator definitely wins for that too. Eg. You can get an exaggerated deformation view of a part, with animation for different input stress. VS a slide where you only get the one value of output at a time
  - jacobr1 4y ago
    Another paradigm are Notebooks. Jupyter style are pretty popular these days, something like Wolfram Alpha's step-by-step mode or this project recently noted on HN https://bbodi.github.io/notecalc3/ https://bbodi.github.io/notecalc3/ are all good examples. Plenty of people use spreadsheets to explicitly chain operations. A specific operation is much less important than the context, dimensional analysis, getting order-of-magnitude or precision correct. Performing operations narrowly is probably operating on the wrong level.
- GeorgeTirebiter 4y ago
  Maybe this is why the abacus has and even continues to be a reliable instrument?
- wildzzz 4y ago
  Just because you don't understand how a calculator works, doesn't make it any less precise than a slide rule. Understanding how your tools work is key for an engineer. That's why we go to school and learn how to do all of these equations by hand only to graduate to using computers to solve them later on. I know how to solve a circuit diagram but would it really be appropriate for me to spend days working the formulas when pspice can spit out an accurate answer in seconds? No, but only if I understand and can accept the limitations of the simulation. I may have to go back and adjust variables to get a worst case analysis so I can add margin to my result that can be passed to the next engineer in the chain. Simulation is just one step in the engineering process. Without knowing the variability of the inputs of the design, you won't get answers that closely match the real world measurements. Being able to simulate something as accurately as possible allows me to iterate a design in a very short amount of time that gives me a much greater understanding of the problem than if I did it all on paper. I can definitely understand that AI kind of fuzzes the simulation math such that it may produce something that isn't reproducible and that's a tough sell. But for the most part, simulations use a massive amount of math that is based on real world formulas that I'd be using anyway to solve the problem by hand.
  - benreesman 4y ago
    I think Walter Bright knows how a calculator works in extreme detail. You do realize who that is right?
    - WalterBright 4y ago
      I've actually implemented IEEE 754 floating point code, from scratch. https://github.com/DigitalMars/dmc/blob/master/src/CORE16/DOUBLE.ASM https://github.com/DigitalMars/dmc/blob/master/src/CORE16/DO... Also, many of the math library functions, though I used "Software Manual for the Elementary Functions" by Cody&Waite for a guide.
      - benreesman 4y ago
        I got started in software late enough that by the time I had a machine that could compile C++ it was Visual Studio and shortly `gcc`, so I missed the first round of your groundbreaking C++ compiler work, but as recently as 2018 I was building all my C++ passed through your excellent Warp preprocessor (which absolutely smoked its predecessor). I imagine you know as much about IEEE 754 as anyone living. Thanks for the all the great software!
- 8note 4y ago
  Can you? You can slide it, sure, but to understand how it works you'd have to be able to make one for yourself, and that understanding is the underlying math, same as with the calculator. Engineers do learn how floats are stored and how computations are done on them to avoid numerical problems while solving whatever differential equations and matrices that they need
Ancapistani 4y ago
I think the idea is that learning to use a slide rule results in a deeper "intuitive understanding" of what the results of calculation should look like. Using a slide rule is also explicitly imprecise, so the user isn't expecting that the result to accurate to n decimal places. They're aware of the imprecision and are likely at least considering whether the level of precision is enough to answer the question they're asking. If I'm looking at a blueprint as see a dimension listed as "1.5mm", my instinct is that anything from 1.47mm to 1.53mm "-ish" is likely to suffice. I'm going to want to understand how that part interfaces with others to make sure it won't cause an issue if it's slightly different. If on the same drawing that dimension is marked as "1.5125mm", my assumption would be that the person who drew it out was specific for a reason. I'm going to be much less likely to try to consider the interface with other parts because I assume that level of precision indicates that it's already been considered. Note that the above is just a conceptual example. I'm not a draftsman, machinist, or an engineer - I've just done enough amateur machining and design work for 3D printing that it popped to mind. Yes, I'm aware that there are implicit and explicit tolerances based on the number of significant digits in a measurement. :)
- WalterBright 4y ago
  One part (the stabilizer trim jackscrew) I designed at Boeing had a tolerance expressed as 4 digits after the decimal point. This was bounced back at me, suggesting I round it to a tighter tolerance with fewer digits. I replied that I had calculated the max and min values based on the rest of the assembly. When a part is delivered, if it is out of tolerance it gets bounced to the engineers to see if it can be salvaged. As the jackscrew was an extremely expensive part, I reasoned that giving it the max possible tolerance meant cost savings on parts that wouldn't have to get diverted to engineering for evaluation. The drawings got approved :-)
  - robocat 4y ago
    Do you start having to specify measurement temperature? 10°C change can change length measurement in the 4th decimal place for say steel? Or is measurement temperature standardised?
cratermoon 4y ago
> There's nothing inherent to a slide rule that gives you a better sense for what the result should be. I strongly disagree, having used a slide rule despite and spent hours exploring how it is the physical representation of logarithms.

WalterBright 4y ago

A slide rule has the advantage in that you can see it working and how it works. A calculator has no such feedback.

Ancapistani 4y ago
> A calculator has no such feedback. That's an interesting thought. There's no reason a calculator has to output only a number - with the computing power and displays at our disposal today, we could easily draw and/or animate a virtual slide rule. A virtual slide rule probably wouldn't be the best option, though. It's just a visual metaphor for how the values in the calculation relate to one another, and it's one that's only going to be useful for someone who has learned to use a slide rule. I wonder if there might be an effective, generic way to present calculations visually in a way that requires little or no training to understand. Has anyone done this?
- operator-name 4y ago
  I think it's not about the final output, but rather how the output changes with the input. Calculators are a terrible tool for this. If the model can be ran at the rate of frames per second, sliders or other non precise inputs are good for this.
  - monkpit 4y ago
    What about graphing calculators? Seeing a graph of solutions (and how the output varies with the input) can give you an intuitive reaction of whether it’s in the right ballpark or not.
  - 8note 4y ago
    A calculator definitely wins for that too. Eg. You can get an exaggerated deformation view of a part, with animation for different input stress. VS a slide where you only get the one value of output at a time
- jacobr1 4y ago
  Another paradigm are Notebooks. Jupyter style are pretty popular these days, something like Wolfram Alpha's step-by-step mode or this project recently noted on HN https://bbodi.github.io/notecalc3/ https://bbodi.github.io/notecalc3/ are all good examples. Plenty of people use spreadsheets to explicitly chain operations. A specific operation is much less important than the context, dimensional analysis, getting order-of-magnitude or precision correct. Performing operations narrowly is probably operating on the wrong level.
GeorgeTirebiter 4y ago
Maybe this is why the abacus has and even continues to be a reliable instrument?
wildzzz 4y ago
Just because you don't understand how a calculator works, doesn't make it any less precise than a slide rule. Understanding how your tools work is key for an engineer. That's why we go to school and learn how to do all of these equations by hand only to graduate to using computers to solve them later on. I know how to solve a circuit diagram but would it really be appropriate for me to spend days working the formulas when pspice can spit out an accurate answer in seconds? No, but only if I understand and can accept the limitations of the simulation. I may have to go back and adjust variables to get a worst case analysis so I can add margin to my result that can be passed to the next engineer in the chain. Simulation is just one step in the engineering process. Without knowing the variability of the inputs of the design, you won't get answers that closely match the real world measurements. Being able to simulate something as accurately as possible allows me to iterate a design in a very short amount of time that gives me a much greater understanding of the problem than if I did it all on paper. I can definitely understand that AI kind of fuzzes the simulation math such that it may produce something that isn't reproducible and that's a tough sell. But for the most part, simulations use a massive amount of math that is based on real world formulas that I'd be using anyway to solve the problem by hand.
- benreesman 4y ago
  I think Walter Bright knows how a calculator works in extreme detail. You do realize who that is right?
  - WalterBright 4y ago
    I've actually implemented IEEE 754 floating point code, from scratch. https://github.com/DigitalMars/dmc/blob/master/src/CORE16/DOUBLE.ASM https://github.com/DigitalMars/dmc/blob/master/src/CORE16/DO... Also, many of the math library functions, though I used "Software Manual for the Elementary Functions" by Cody&Waite for a guide.
    - benreesman 4y ago
      I got started in software late enough that by the time I had a machine that could compile C++ it was Visual Studio and shortly `gcc`, so I missed the first round of your groundbreaking C++ compiler work, but as recently as 2018 I was building all my C++ passed through your excellent Warp preprocessor (which absolutely smoked its predecessor). I imagine you know as much about IEEE 754 as anyone living. Thanks for the all the great software!
8note 4y ago
Can you? You can slide it, sure, but to understand how it works you'd have to be able to make one for yourself, and that understanding is the underlying math, same as with the calculator. Engineers do learn how floats are stored and how computations are done on them to avoid numerical problems while solving whatever differential equations and matrices that they need

Ancapistani 4y ago

I think the idea is that learning to use a slide rule results in a deeper "intuitive understanding" of what the results of calculation should look like. Using a slide rule is also explicitly imprecise, so the user isn't expecting that the result to accurate to n decimal places. They're aware of the imprecision and are likely at least considering whether the level of precision is enough to answer the question they're asking. If I'm looking at a blueprint as see a dimension listed as "1.5mm", my instinct is that anything from 1.47mm to 1.53mm "-ish" is likely to suffice. I'm going to want to understand how that part interfaces with others to make sure it won't cause an issue if it's slightly different. If on the same drawing that dimension is marked as "1.5125mm", my assumption would be that the person who drew it out was specific for a reason. I'm going to be much less likely to try to consider the interface with other parts because I assume that level of precision indicates that it's already been considered. Note that the above is just a conceptual example. I'm not a draftsman, machinist, or an engineer - I've just done enough amateur machining and design work for 3D printing that it popped to mind. Yes, I'm aware that there are implicit and explicit tolerances based on the number of significant digits in a measurement. :)

WalterBright 4y ago
One part (the stabilizer trim jackscrew) I designed at Boeing had a tolerance expressed as 4 digits after the decimal point. This was bounced back at me, suggesting I round it to a tighter tolerance with fewer digits. I replied that I had calculated the max and min values based on the rest of the assembly. When a part is delivered, if it is out of tolerance it gets bounced to the engineers to see if it can be salvaged. As the jackscrew was an extremely expensive part, I reasoned that giving it the max possible tolerance meant cost savings on parts that wouldn't have to get diverted to engineering for evaluation. The drawings got approved :-)
- robocat 4y ago
  Do you start having to specify measurement temperature? 10°C change can change length measurement in the 4th decimal place for say steel? Or is measurement temperature standardised?

cratermoon 4y ago

> There's nothing inherent to a slide rule that gives you a better sense for what the result should be. I strongly disagree, having used a slide rule despite and spent hours exploring how it is the physical representation of logarithms.