more feng shui

README.md

@@ -1,6 +1,6 @@
-# A minimalist calculator for fermi estimation
+# A minimalist calculator for f estimation
 
-This project is a minimalist, stack-based DSL for Fermi estimation. It can multiply and divide scalars, lognormals and beta distributions.
+This project is a minimalist, stack-based DSL for f estimation. It can multiply and divide scalars, lognormals and beta distributions.
 
 ## Motivation
 
@@ -11,7 +11,7 @@ Sometimes, [Squiggle](https://github.com/quantified-uncertainty/squiggle), [simp
 Here is an example
 
 ```
-$ go run fermi.go
+$ go run f.go
 5000000 12000000
 => 5.0M 12.0M
 * beta 1 200
@@ -31,7 +31,7 @@ $ go run fermi.go
 Perhaps this example is more understandable with comments and better units:
 
 ```
-$ sed -u "s|#.*||" | sed -u 's|M|000000|g' | go run fermi.go
+$ sed -u "s|#.*||" | sed -u 's|M|000000|g' | go run f.go
 5M 12M # number of people living in Chicago
 => 5.0M 12.0M
 * beta 1 200 # fraction of people that have a piano
@@ -74,12 +74,40 @@ x
 
 The difference between `=: x` and `=. y` is that `=.` clears the stack after the assignment.
 
+If you type "help", you can see a small grammar:
+
+```
+help
+   Operation | Variable assignment | Special
+      Operation:                             operator operand
+            operator:                        (empty) | * | / | + | -
+            operand:                         scalar | lognormal | beta | variable
+              lognormal:                     low high
+              beta:                          beta alpha beta
+      Variable assignment:                   =: variable_name
+      Clear stack:                           . | c | clear
+      Variable assignment and clear stack:   =. variable_name
+      Other special operations:              help | debug | exit
+    Examples: 
+      + 2
+      / 2.5
+      * 1 10 (interpreted as lognormal)
+      + 1 10
+      * beta 1 10
+      1 10 (multiplication taken as default operation)
+        =: x
+      .
+      1 100
+      + x
+      exit
+```
+
 ## Installation
 
 ```
 make build
 sudo make install
-f # rather than the previous go run fermi.go
+f # rather than the previous go run f.go
 ```
 
 Why use make instead of the built-in go commands? Because the point of make is to be able to share command-line recipes. 
@@ -93,8 +121,8 @@ 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 fermi.go | tee -a output.log
+tee -a input.log | go run f.go | tee -a output.log
-tee -a io.log | go run fermi.go | tee -a io.log
+tee -a io.log | go run f.go | tee -a io.log
 
 function f(){
   sed -u "s|#.*||" | 
@@ -114,8 +142,17 @@ Note that these sed commands are just hacks, and won't parse e.g., `3.5K` correc
 - Sums and divisions now also supported
 - For things between 0 and 1, consider using a beta distribution
 
+## Different levels of complexity
+
+The top level f.go file (400 lines) has a bunch of complexity: variables, parenthesis, samples, beta distributions. In the simple/ folder:
+
+- f_simple.go (370 lines) strips variables and parenthesis, but keeps beta distributions, samples, and addition and substraction
+- f_minimal.go (140 lines) strips everything that isn't lognormal and scalar multiplication and addition, plus a few debug options.
+
 ## Roadmap 
 
+Done: 
+
 - [x] Write README
 - [x] Add division?
 - [x] Read from file?
@@ -124,13 +161,10 @@ Note that these sed commands are just hacks, and won't parse e.g., `3.5K` correc
   - [x] Use a sed filter? 
 - [x] Add show more info version
 - [x] Scalar multiplication and division
-- [ ] Program into a small device, like a calculator?
-- [-] Think of some way of calling bc
 - [x] Think how to integrate with squiggle.c to draw samples
   - [x] Copy the time to botec go code
   - [x] Define samplers
   - [x] Call those samplers when operating on distributions that can't be operted on algebraically
-- [ ] Think about how to draw a histogram from samples
 - [x] Display output more nicely, with K/M/B/T
 - [x] Consider the following: make this into a stack-based DSL, with:
   - [x] Variables that can be saved to and then displayed
@@ -140,10 +174,20 @@ Note that these sed commands are just hacks, and won't parse e.g., `3.5K` correc
   - Joint types
   - Enums
 - [x] Fix correlation problem, by spinning up a new randomness thing every time some serial computation is done.
-- [ ] Maintain *both* a more complex thing that's more featureful *and* the more simple multiplication of lognormals thing.
+- [x] Clean up error code. Right now only needed for division
-- [ ] Clean up error code. Right now only needed for division
+- [x] Maintain *both* a more complex thing that's more featureful *and* the more simple multiplication of lognormals thing.
+
+To (possibly) do:
+
+- [ ] Document parenthesis syntax
+- [ ] Allow input with K/M/T
+- [ ] Add functions. Now easier to do with an explicit representation of the stakc
+- [ ] Think about how to draw a histogram from samples
 - [ ] Dump samples to file
 - [ ] Represent samples/statistics in some other way
 - [ ] Perhaps use qsort rather than full sorting
+- [ ] Program into a small device, like a calculator?
 
-Some possible syntax for a more expressive stack-based DSL (now implemented)
+Discarded: 
+
+- [ ] ~~Think of some way of calling bc~~

f.go

@@ -14,7 +14,6 @@ import (
 )
 
 /* Types and interfaces */
-
 type Stack struct {
 	old_dist Dist
 	vars     map[string]Dist
@@ -52,7 +51,6 @@ func (p Scalar) Samples() []float64 {
 
 func (ln Lognormal) Samples() []float64 {
 	sampler := func(r sample.Src) float64 { return sample.Sample_to(ln.low, ln.high, r) }
-	// return sample.Sample_parallel(sampler, N_SAMPLES)
 	// Can't do parallel because then I'd have to await throughout the code
 	return sample.Sample_serially(sampler, N_SAMPLES)
 }
@@ -162,7 +160,6 @@ func operateDistsAsSamples(dist1 Dist, dist2 Dist, op string) (Dist, error) {
 		}
 	}
 
-	// fmt.Printf("%v\n", zs)
 	return FilledSamples{xs: zs}, nil
 }
 
@@ -235,14 +232,12 @@ func divideDists(old_dist Dist, new_dist Dist) (Dist, error) {
 		{
 			switch n := new_dist.(type) {
 			case Lognormal:
-				// to do: check division by zero
 				if n.high == 0 || n.low == 0 {
 					fmt.Println("Error: Can't divide by 0.0")
 					return nil, errors.New("Error: division by zero")
 				}
 				return multiplyLogDists(o, Lognormal{low: 1.0 / n.high, high: 1.0 / n.low}), nil
 			case Scalar:
-				// to do: check division by zero
 				if n == 0.0 {
 					fmt.Println("Error: Can't divide by 0.0")
 					return nil, errors.New("Error: division by zero scalar")
@@ -258,7 +253,6 @@ func divideDists(old_dist Dist, new_dist Dist) (Dist, error) {
 			case Lognormal:
 				return multiplyLogDists(Lognormal{low: float64(o), high: float64(o)}, Lognormal{low: 1.0 / n.high, high: 1.0 / n.low}), nil
 			case Scalar:
-				// to do: check division by zero
 				if n == 0.0 {
 					fmt.Println("Error: Can't divide by 0.0")
 					return nil, errors.New("Error: division by zero scalar")
@@ -290,9 +284,11 @@ func operateDists(old_dist Dist, new_dist Dist, op string) (Dist, error) {
 }
 
 /* Parser and repl */
-func parseLineIntoOpAndDist(line string, vars map[string]Dist) (string, Dist, error) {
+func parseWordsErr(err_msg string) (string, Dist, error) {
+	return "", nil, printAndReturnErr(err_msg)
+}
+func parseWordsIntoOpAndDist(words []string, vars map[string]Dist) (string, Dist, error) {
 
-	words := strings.Split(strings.TrimSpace(line), " ")
 	op := ""
 	var dist Dist
 
@@ -304,13 +300,9 @@ func parseLineIntoOpAndDist(line string, vars map[string]Dist) (string, Dist, er
 		op = "*" // later, change the below to
 	}
 
-	parseLineErr := func(err_msg string) (string, Dist, error) {
-		return "", nil, printAndReturnErr(err_msg)
-	}
-
 	switch len(words) {
 	case 0:
-		return parseLineErr("Operator must have operand; can't operate on nothing")
+		return parseWordsErr("Operator must have operand; can't operate on nothing")
 	case 1:
 		var_word, var_word_exists := vars[words[0]]
 		single_float, err1 := strconv.ParseFloat(words[0], 64) // abstract this away to search for K/M/B/T/etc.
@@ -320,13 +312,13 @@ func parseLineIntoOpAndDist(line string, vars map[string]Dist) (string, Dist, er
 		case err1 == nil:
 			dist = Scalar(single_float)
 		case err1 != nil && !var_word_exists:
-			return parseLineErr("Trying to operate on a scalar, but scalar is neither a float nor an assigned variable")
+			return parseWordsErr("Trying to operate on a scalar, but scalar is neither a float nor an assigned variable")
 		}
 	case 2:
 		new_low, err1 := strconv.ParseFloat(words[0], 64)
 		new_high, err2 := strconv.ParseFloat(words[1], 64)
 		if err1 != nil || err2 != nil {
-			return parseLineErr("Trying to operate by a distribution, but distribution is not specified as two floats")
+			return parseWordsErr("Trying to operate by a distribution, but distribution is not specified as two floats")
 		}
 		dist = Lognormal{low: new_low, high: new_high}
 	case 3:
@@ -334,17 +326,16 @@ func parseLineIntoOpAndDist(line string, vars map[string]Dist) (string, Dist, er
 			a, err1 := strconv.ParseFloat(words[1], 64)
 			b, err2 := strconv.ParseFloat(words[2], 64)
 			if err1 != nil || err2 != nil {
-				return parseLineErr("Trying to specify a beta distribution? Try beta 1 2")
+				return parseWordsErr("Trying to specify a beta distribution? Try beta 1 2")
 			}
 			dist = Beta{a: a, b: b}
 		} else {
-			return parseLineErr("Input not understood or not implemented yet")
+			return parseWordsErr("Input not understood or not implemented yet")
 		}
 	default:
-		return parseLineErr("Input not understood or not implemented yet")
+		return parseWordsErr("Input not understood or not implemented yet")
 	}
 	return op, dist, nil
-
 }
 
 /* Combine old dist and new line */
@@ -389,7 +380,7 @@ replForLoop:
 			// fmt.Println()
 			// continue replForLoop
 		default:
-			op, new_dist, err := parseLineIntoOpAndDist(new_line, stack.vars)
+			op, new_dist, err := parseWordsIntoOpAndDist(words, stack.vars)
 			if err != nil {
 				continue replForLoop
 			}

simple/f_minimal.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"git.nunosempere.com/NunoSempere/fermi/pretty"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Lognormal struct {
+	low  float64
+	high float64
+}
+
+const HELP_MSG = "  Operation | Variable assignment | Special\n" +
+	"    Operation:                             operator operand\n" +
+	"          operator:                        (empty) | * | / | + | -\n" +
+	"          operand:                         scalar | lognormal\n" +
+	"            lognormal:                     low high\n" +
+	"    Clear stack:                           . | c | clear\n" +
+	"    Other special operations:              help | debug | exit\n" +
+	"  Examples: \n" +
+	"    / 2.5\n" +
+	"    * 1 10 (interpreted as lognormal)\n" +
+	"    / 1 10\n" +
+	"    1 10 (multiplication taken as default operation)\n" +
+	"    .\n" +
+	"    exit\n"
+const NORMAL90CONFIDENCE = 1.6448536269514727
+const N_SAMPLES = 100_000
+
+func prettyPrintLognormal(l Lognormal) {
+	fmt.Printf("=> ")
+	pretty.PrettyPrint2Floats(l.low, l.high)
+	fmt.Println()
+}
+
+func printAndReturnErr(err_msg string) error {
+	fmt.Println(err_msg)
+	fmt.Println(HELP_MSG)
+	return errors.New(err_msg)
+}
+
+func multiplyLogDists(l1 Lognormal, l2 Lognormal) Lognormal {
+	logmean1 := (math.Log(l1.high) + math.Log(l1.low)) / 2.0
+	logstd1 := (math.Log(l1.high) - math.Log(l1.low)) / (2.0 * NORMAL90CONFIDENCE)
+
+	logmean2 := (math.Log(l2.high) + math.Log(l2.low)) / 2.0
+	logstd2 := (math.Log(l2.high) - math.Log(l2.low)) / (2.0 * NORMAL90CONFIDENCE)
+
+	logmean_product := logmean1 + logmean2
+	logstd_product := math.Sqrt(logstd1*logstd1 + logstd2*logstd2)
+
+	h := logstd_product * NORMAL90CONFIDENCE
+	loglow := logmean_product - h
+	loghigh := logmean_product + h
+	return Lognormal{low: math.Exp(loglow), high: math.Exp(loghigh)}
+}
+
+func divideLogDists(l1 Lognormal, l2 Lognormal) (Lognormal, error) {
+	if l2.high == 0 || l2.low == 0 {
+		fmt.Println("Error: Can't divide by 0.0")
+		return Lognormal{}, errors.New("Error: division by zero")
+	}
+	return multiplyLogDists(l1, Lognormal{low: 1.0 / l2.high, high: 1.0 / l2.low}), nil
+}
+
+func parseWordsErr(err_msg string) (string, Lognormal, error) {
+	return "", Lognormal{}, printAndReturnErr(err_msg)
+}
+func parseWordsIntoOpAndDist(words []string) (string, Lognormal, error) {
+	op := ""
+	var dist Lognormal
+
+	switch words[0] {
+	case "*", "/":
+		op = words[0]
+		words = words[1:]
+	default:
+		op = "*"
+	}
+
+	switch len(words) {
+	case 0:
+		return parseWordsErr("Operator must have operand; can't operate on nothing")
+	case 1:
+		single_float, err := strconv.ParseFloat(words[0], 64) // abstract this away to search for K/M/B/T/etc.
+		if err != nil {
+			return parseWordsErr("Trying to operate on a scalar, but scalar is neither a float nor an assigned variable")
+		}
+		dist = Lognormal{low: single_float, 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 {
+			return parseWordsErr("Trying to operate by a distribution, but distribution is not specified as two floats")
+		}
+		dist = Lognormal{low: new_low, high: new_high}
+	default:
+		return parseWordsErr("Input not understood or not implemented yet")
+	}
+	return op, dist, nil
+}
+
+func main() {
+	reader := bufio.NewReader(os.Stdin)
+	old_dist := Lognormal{low: 1, high: 1}
+
+replForLoop:
+	for {
+
+		new_line, _ := reader.ReadString('\n')
+		words := strings.Split(strings.TrimSpace(new_line), " ")
+
+		if strings.TrimSpace(new_line) == "" {
+			continue replForLoop
+		}
+
+		op, new_dist, err := parseWordsIntoOpAndDist(words)
+		if err != nil {
+			continue replForLoop
+		}
+		switch op {
+		case "*":
+			old_dist = multiplyLogDists(old_dist, new_dist)
+		case "/":
+			result_dist, err := divideLogDists(old_dist, new_dist)
+			if err != nil {
+				continue replForLoop
+			}
+			old_dist = result_dist
+
+		}
+		prettyPrintLognormal(old_dist)
+	}
+}

simple/f_simple.go

@@ -63,7 +63,7 @@ func (fs FilledSamples) Samples() []float64 {
 const HELP_MSG = "  Operation | Variable assignment | Special\n" +
 	"    Operation:                             operator operand\n" +
 	"          operator:                        (empty) | * | / | + | -\n" +
-	"          operand:                         scalar | lognormal | beta | variable\n" +
+	"          operand:                         scalar | lognormal | beta\n" +
 	"            lognormal:                     low high\n" +
 	"            beta:                          beta alpha beta\n" +
 	"    Clear stack:                           . | c | clear\n" +
@@ -279,9 +279,11 @@ func operateDists(old_dist Dist, new_dist Dist, op string) (Dist, error) {
 }
 
 /* Parser and repl */
-func parseLineIntoOpAndDist(line string) (string, Dist, error) {
+func parseWordsErr(err_msg string) (string, Dist, error) {
+	return "", nil, printAndReturnErr(err_msg)
+}
+func parseWordsIntoOpAndDist(words []string) (string, Dist, error) {
 
-	words := strings.Split(strings.TrimSpace(line), " ")
 	op := ""
 	var dist Dist
 
@@ -293,24 +295,20 @@ func parseLineIntoOpAndDist(line string) (string, Dist, error) {
 		op = "*" // later, change the below to
 	}
 
-	parseLineErr := func(err_msg string) (string, Dist, error) {
-		return "", nil, printAndReturnErr(err_msg)
-	}
-
 	switch len(words) {
 	case 0:
-		return parseLineErr("Operator must have operand; can't operate on nothing")
+		return parseWordsErr("Operator must have operand; can't operate on nothing")
 	case 1:
 		single_float, err := strconv.ParseFloat(words[0], 64) // abstract this away to search for K/M/B/T/etc.
 		if err != nil {
-			return parseLineErr("Trying to operate on a scalar, but scalar is neither a float nor an assigned variable")
+			return parseWordsErr("Trying to operate on a scalar, but scalar is neither a float nor an assigned variable")
 		}
 		dist = Scalar(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 {
-			return parseLineErr("Trying to operate by a distribution, but distribution is not specified as two floats")
+			return parseWordsErr("Trying to operate by a distribution, but distribution is not specified as two floats")
 		}
 		dist = Lognormal{low: new_low, high: new_high}
 	case 3:
@@ -318,14 +316,14 @@ func parseLineIntoOpAndDist(line string) (string, Dist, error) {
 			a, err1 := strconv.ParseFloat(words[1], 64)
 			b, err2 := strconv.ParseFloat(words[2], 64)
 			if err1 != nil || err2 != nil {
-				return parseLineErr("Trying to specify a beta distribution? Try beta 1 2")
+				return parseWordsErr("Trying to specify a beta distribution? Try beta 1 2")
 			}
 			dist = Beta{a: a, b: b}
 		} else {
-			return parseLineErr("Input not understood or not implemented yet")
+			return parseWordsErr("Input not understood or not implemented yet")
 		}
 	default:
-		return parseLineErr("Input not understood or not implemented yet")
+		return parseWordsErr("Input not understood or not implemented yet")
 	}
 	return op, dist, nil
 
@@ -358,7 +356,7 @@ replForLoop:
 			continue replForLoop
 		}
 
-		op, new_dist, err := parseLineIntoOpAndDist(new_line)
+		op, new_dist, err := parseWordsIntoOpAndDist(words)
 		if err != nil {
 			continue replForLoop
 		}