fix distributional division

README.md

@@ -1,33 +1,101 @@
 # A minimalist calculator for fermi estimation
 
-This project contains a minimalist calculator for Fermi estimation. Right now, it just multiplies lognormals.
+This project contains a minimalist command-line calculator for Fermi estimation. For now, it just multiplies lognormals.
 
 ## Motivation
 
 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.
 
-## An example
+## Usage
 
+Here is an example
 
+```
+$ go run f.go
+5000000 12000000
+=> 5000000.0 12000000.0
+0.002 0.01
+=> 13859.5 86583.4
+30 180
+=> 706832.8 9167656.0
+/ 48 52
+=> 14139.1 183614.7
+/ 5 6
+=> 2573.1 33632.0
+/ 6 8
+=> 368.4 4893.5
+/ 60
+=> 6.1 81.6
+```
 
-Perhaps this example might be clearer with comment
+Perhaps this example is more understandable with comments and better units:
 
+```
+$ sed -u "s|#.*||" | sed -u 's|M|000000|g' | go run f.go
+5M 12M # number of people living in Chicago
+=> 5000000.0 12000000.0
+0.002 0.01 # fraction of people that have a piano
+=> 13859.5 86583.4
+30 180 # minutes it takes to tune a piano, including travel time
+=> 706832.8 9167656.0
+/ 48 52 # weeks a year that piano tuners work for
+=> 14139.1 183614.7
+/ 5 6 # days a week in which piano tuners work
+=> 2573.1 33632.0
+/ 6 8 # hours a day in which piano tuners work
+=> 368.4 4893.5
+/ 60 # minutes to an hour
+=> 6.1 81.6
+# ^ piano tuners in Chicago
+```
 
-## 
+## Installation
 
-To do:
+```
+make build
+sudo make install
+f # rather than the previous go run f.go
+```
 
-- [ ] Write README
-- [ ] Add show more info version
-- [ ] Add division?
-- [ ] Read from file?
-- [ ] Save to file?
+Why use make instead of the built-in go commands? Because the point of make is to be able to share command-line recipes. 
+
+## Usage together with standard Linux utilities
+
+```bash
+f
+sed -u "s|#.*||" | sed -u 's|M|000000|g' | f
+
+cat more/piano-tuners.f | f
+cat more/piano-tuners-commented.f | sed -u "s|#.*||" | sed -u 's|M|000000|g' | f
+
+tee -a input.log | go run f.go | tee -a output.log
+tee -a io.log | go run f.go | tee -a io.log
+
+function f(){
+  sed -u "s|#.*||" | 
+  sed -u "s|//.*||" | 
+  sed -u 's|K|000|g' | 
+  sed -u 's|M|000000|g' | 
+  sed -u 's|B|000000000|g' | 
+  /usr/bin/f
+}
+```
+
+## Tips & tricks
+
+Conceptually clearer to have all the multiplications first and then all the divisions
+
+## Roadmap 
+
+- [x] Write README
+- [x] Add division?
+- [x] Read from file?
+- [x] Save to file?
+- [x] Allow comments?
+  - [x] Use a sed filter? 
+- [x] Add show more info version
+- [x] Scalar multiplication and division
 - [ ] Program into a small device, like a calculator?
-- [ ] Allow comments?
-  - Use a sed filter? 
 - [ ] Think of some way of calling bc
-
-
-go run main.go < model.f
-sed 's|//||' model.f | go run main.go
-
+- [ ] Think how to integrate with squiggle.c to draw samples
+- [ ] Think about how to draw a histogram from samples

f.go

@@ -42,46 +42,136 @@ func combineBounds(old_low, old_high, new_low, new_high float64) (float64, float
 
 func main() {
 	reader := bufio.NewReader(os.Stdin)
+
 	var old_low, old_high float64
+	var input string
+	var err1, err2 error
+	for {
+		input, _ = reader.ReadString('\n')
+		input = strings.TrimSpace(input)
+		words := strings.Split(input, " ")
+		if len(words) != 2 {
+			fmt.Println("Please enter two floats separated by a space, like: 1 10")
+			continue
+		}
+		old_low, err1 = strconv.ParseFloat(words[0], 64)
+		old_high, err2 = strconv.ParseFloat(words[1], 64)
+		if err1 != nil || err2 != nil {
+			fmt.Println("Please enter two floats separated by a space, like: 1 10")
+			continue
+		}
+		break
 
-	input, _ := reader.ReadString('\n')
-	input = strings.TrimSpace(input)
-
-	tokens := strings.Split(input, " ")
-	if len(tokens) != 2 {
-		fmt.Println("Please enter exactly two floats.")
-		return
 	}
-	old_low, err1 := strconv.ParseFloat(tokens[0], 64)
-	old_high, err2 := strconv.ParseFloat(tokens[1], 64)
-	if err1 != nil || err2 != nil {
-		fmt.Println("Invalid input. Please ensure you enter two floats.")
-		return
-	}
-
 	fmt.Printf("=> %.1f %.1f\n", old_low, old_high)
 
+	error_msg_cont := "Valid inputs: 2 || * 2 || / 2 || 2 20 || * 2 20 || / 2 20 || i || e"
+EventForLoop:
 	for {
-		// fmt.Println("Enter another two floats separated by a space:")
 		input, _ = reader.ReadString('\n')
 		if strings.TrimSpace(input) == "" {
-			break // Exit if no input is given
+			continue EventForLoop
+		}
+		words := strings.Split(strings.TrimSpace(input), " ")
+
+		var new_low, new_high float64
+
+		switch words[0] {
+		case "*":
+			switch len(words) {
+			case 1:
+				fmt.Println("Can't multiply by nothing")
+				fmt.Println(error_msg_cont)
+				continue EventForLoop
+			case 2:
+				single_float, err1 := strconv.ParseFloat(words[1], 64)
+				if err1 != nil {
+					fmt.Println("Trying to multiply by a scalar, but scalar is not a float")
+					fmt.Println(error_msg_cont)
+					continue EventForLoop
+				}
+				new_low = single_float
+				new_high = single_float
+			case 3:
+				new_low, err1 = strconv.ParseFloat(words[1], 64)
+				new_high, err2 = strconv.ParseFloat(words[2], 64)
+				if err1 != nil || err2 != nil {
+					fmt.Println(error_msg_cont)
+					fmt.Println("Trying to multiply by a distribution, but distribution is not specified as two floats")
+					continue EventForLoop
+				}
+			default:
+				fmt.Println("Trying to multiply by something, but this something is neither a scalar nor a distribution")
+				fmt.Println(error_msg_cont)
+				continue EventForLoop
+			}
+		case "/":
+			switch len(words) {
+			case 1:
+				fmt.Println("Can't divide by nothing")
+				fmt.Println(error_msg_cont)
+				continue EventForLoop
+			case 2:
+				single_float, err1 := strconv.ParseFloat(words[1], 64)
+				if err1 != nil {
+					fmt.Println("Trying to divide by a scalar, but scalar is not a float")
+					fmt.Println(error_msg_cont)
+					continue EventForLoop
+				}
+				new_low = 1.0 / single_float
+				new_high = 1.0 / single_float
+			case 3:
+				new_low, err1 = strconv.ParseFloat(words[1], 64)
+				new_high, err2 = strconv.ParseFloat(words[2], 64)
+				if err1 != nil || err2 != nil {
+					fmt.Println("Trying to divide by a distribution, but distribution is not specified as two floats")
+					fmt.Println(error_msg_cont)
+					continue EventForLoop
+				}
+				tmp := new_low
+				new_low = 1.0 / new_high
+				new_high = 1.0 / tmp
+			default:
+				fmt.Println("Trying to divide by something, but this something is neither a scalar nor a distribution")
+			}
+		default:
+			switch len(words) {
+			case 0:
+				continue EventForLoop
+			case 1:
+				switch words[0] {
+				case "i":
+					fmt.Printf("=> %.1f %.1f\n", old_low, old_high)
+					logmean_old, logstd_old := boundsToLogParams(old_low, old_high)
+					fmt.Printf("=> Lognormal, with logmean: %.1f, logstd: %.1f\n", logmean_old, logstd_old)
+					continue EventForLoop
+				case "e":
+					break EventForLoop
+				default:
+					single_float, err1 := strconv.ParseFloat(words[0], 64)
+					if err1 != nil {
+						fmt.Println("Unrecognized command")
+						fmt.Println(error_msg_cont)
+						continue EventForLoop
+					}
+					new_low = single_float
+					new_high = single_float
+				}
+			case 2:
+				new_low, err1 = strconv.ParseFloat(words[0], 64)
+				new_high, err2 = strconv.ParseFloat(words[1], 64)
+				if err1 != nil || err2 != nil {
+					fmt.Println("Trying to multiply by a distribution, but distribution is not specified as two floats")
+					fmt.Println(error_msg_cont)
+					continue EventForLoop
+				}
+			default:
+				fmt.Println("No operation takes more than 3 words")
+				fmt.Println(error_msg_cont)
+				continue EventForLoop
+			}
 		}
 
-		tokens := strings.Split(strings.TrimSpace(input), " ")
-		if len(tokens) != 2 {
-			fmt.Println("Please enter exactly two floats.")
-			continue
-		}
-
-		new_low, err1 := strconv.ParseFloat(tokens[0], 64)
-		new_high, err2 := strconv.ParseFloat(tokens[1], 64)
-		if err1 != nil || err2 != nil {
-			fmt.Println("Invalid input. Please ensure you enter two floats.")
-			continue
-		}
-
-		// Use the abstracted function for combining floats
 		old_low, old_high = combineBounds(old_low, old_high, new_low, new_high)
 		fmt.Printf("=> %.1f %.1f\n", old_low, old_high)
 	}

more/f.sh

@@ -1,9 +1,12 @@
 #!/bin/bash
-#while IFS= read -r line; do echo "$line" | sed 's| //.*||' | go run main.go
 
-# while IFS= read -r line; do echo "$line" | sed 's|//.*||'; done | go run main.go
+function f(){
+  sed -u "s|#.*||" | 
+  sed -u "s|//.*||" | 
+  sed -u 's|K|000|g' | 
+  sed -u 's|M|000000|g' | 
+  sed -u 's|B|000000000|g' | 
+  /usr/bin/f
+}
 
-
-sed -u 's|//.*||' | go run main.go
-# ^ sed unbuffered.
-# cat | tee -a log.f | sed -u 's|//.*||' | go run main.go | tee -a log.f
+# f

more/model.f

@@ -1,2 +0,0 @@
-1 10 
-2 20

more/piano-tuners-commented.f

@@ -0,0 +1,9 @@
+5M 12M # number of people living in Chicago
+0.002 0.01 # fraction of people that have a piano
+30 180 # minutes it takes to tune a piano, including travel time
+/ 48 52 # weeks a year that piano tuners work for
+/ 5 6 # days a week in which piano tuners work
+/ 6 8 # hours a day in which piano tuners work
+/ 60 # minutes to an hour
+# ^ piano tuners in Chicago
+

more/piano-tuners.f

@@ -0,0 +1,7 @@
+5000000 12000000
+0.002 0.01
+30 180
+/ 48 52
+/ 5 6
+/ 6 8
+/ 60

pianotuners.f

@@ -1,9 +0,0 @@
-Please enter exactly two floats.
-4000000 12000000
-=> 4000000.0 12000000.0
-0.005 0.01
-=> 25587.7 93795.1
-1/365 1/365
-Invalid input. Please ensure you enter two floats.
-1 1
-=> 25587.7 93795.1