102 lines
2.5 KiB
Markdown
102 lines
2.5 KiB
Markdown
# A minimalist calculator for fermi estimation
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This project contains a minimalist command-line calculator for Fermi estimation. For now, it just multiplies lognormals.
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## Motivation
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Sometimes, [Squiggle](https://github.com/quantified-uncertainty/squiggle), [simple squiggle](https://git.nunosempere.com/quantified.uncertainty/simple-squiggle) or [squiggle.c](https://git.nunosempere.com/personal/squiggle.c) are still too complicated and un-unix-like.
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## Usage
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Here is an example
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```
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$ go run f.go
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5000000 12000000
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=> 5000000.0 12000000.0
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0.002 0.01
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=> 13859.5 86583.4
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30 180
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=> 706832.8 9167656.0
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/ 48 52
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=> 14139.1 183614.7
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/ 5 6
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=> 2573.1 33632.0
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/ 6 8
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=> 368.4 4893.5
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/ 60
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=> 6.1 81.6
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```
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Perhaps this example is more understandable with comments and better units:
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```
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$ sed -u "s|#.*||" | sed -u 's|M|000000|g' | go run f.go
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5M 12M # number of people living in Chicago
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=> 5000000.0 12000000.0
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0.002 0.01 # fraction of people that have a piano
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=> 13859.5 86583.4
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30 180 # minutes it takes to tune a piano, including travel time
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=> 706832.8 9167656.0
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/ 48 52 # weeks a year that piano tuners work for
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=> 14139.1 183614.7
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/ 5 6 # days a week in which piano tuners work
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=> 2573.1 33632.0
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/ 6 8 # hours a day in which piano tuners work
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=> 368.4 4893.5
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/ 60 # minutes to an hour
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=> 6.1 81.6
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# ^ piano tuners in Chicago
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```
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## Installation
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```
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make build
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sudo make install
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f # rather than the previous go run f.go
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```
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Why use make instead of the built-in go commands? Because the point of make is to be able to share command-line recipes.
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## Usage together with standard Linux utilities
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```bash
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f
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sed -u "s|#.*||" | sed -u 's|M|000000|g' | f
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cat more/piano-tuners.f | f
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cat more/piano-tuners-commented.f | sed -u "s|#.*||" | sed -u 's|M|000000|g' | f
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tee -a input.log | go run f.go | tee -a output.log
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tee -a io.log | go run f.go | tee -a io.log
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function f(){
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sed -u "s|#.*||" |
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sed -u "s|//.*||" |
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sed -u 's|K|000|g' |
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sed -u 's|M|000000|g' |
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sed -u 's|B|000000000|g' |
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/usr/bin/f
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}
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```
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## Tips & tricks
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Conceptually clearer to have all the multiplications first and then all the divisions
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## Roadmap
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- [x] Write README
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- [x] Add division?
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- [x] Read from file?
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- [x] Save to file?
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- [x] Allow comments?
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- [x] Use a sed filter?
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- [x] Add show more info version
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- [x] Scalar multiplication and division
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- [ ] Program into a small device, like a calculator?
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- [ ] Think of some way of calling bc
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- [ ] Think how to integrate with squiggle.c to draw samples
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- [ ] Think about how to draw a histogram from samples
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