update: represent 90% confidence intervals at the end

README.md

@@ -8,7 +8,7 @@
 
 It may be useful for testing correctness of limited features of the full Squiggle, or for sanity-checking the validity of some Squiggle models.
 
-![](imgs/simple-squiggle.png)
+![](imgs/simple-squiggle2.png)
 
 ## Built with
 
@@ -94,7 +94,10 @@ Model: ( 2000000000 to 20000000000 ) / ( (1800000 to 2500000) * (0.25 to 0.75) *
         -> lognormal(9.53, 1.60)
 
 => lognormal(9.530291704996749, 1.596443005980748)
+   ( => ~996.6270585961881 to ~190271.4039258926 )
+
 ----------------------------------------------------
+
 ```
 
 For ease of representation, the intermediary outputs are printed only to two decimal points. But this is just a display decision; the innards of the program work with the full set of decimals.

src/cli.js

@@ -15,7 +15,10 @@ let runTransformer = (string) => {
   let result = transformer(string, print);
   print("");
   console.groupEnd();
-  console.log(`=> ${result}`);
+  console.log(`=> ${result[0]}`);
+  console.log(`   ( => ${result[1]} )`);
+  console.log("");
+
   print("-".repeat(52));
   console.log("");
 };

src/index.js

@@ -137,7 +137,6 @@ let transformerInner = (string) => {
           let newMean = mean1 - mean2;
           let newStd = Math.sqrt(std1 ** 2 + std2 ** 2);
           return createLogarithmNode(newMean, newStd);
-          return new math.SymbolNode("xx");
         } else if (isLognormalDividedByNumber) {
           let lognormalFactors = getFactors(node.args[0]);
           let mean = lognormalFactors[0];
@@ -172,8 +171,9 @@ let transformerInner = (string) => {
   return transformed;
 };
 
+const normal95confidencePoint = 1.6448536269514722;
+
 let from90PercentCI = (low, high) => {
-  let normal95confidencePoint = 1.6448536269514722;
   let logLow = Math.log(low);
   let logHigh = Math.log(high);
   let mu = (logLow + logHigh) / 2;
@@ -181,6 +181,14 @@ let from90PercentCI = (low, high) => {
   return [mu, sigma];
 };
 
+let to90PercentCI = (mu, sigma) => {
+  let logHigh = mu + normal95confidencePoint * sigma;
+  let logLow = mu - normal95confidencePoint * sigma;
+  let high = Math.exp(logHigh);
+  let low = Math.exp(logLow);
+  return [low, high];
+};
+
 let simplePreprocessor = (string) => {
   // left for documentation purposes only
   function replacer(match, p1, p2) {
@@ -197,7 +205,7 @@ let simplePreprocessor = (string) => {
 
 // simplePreprocessor("1 to 10 + 1 to 20");
 
-let customToStringHandler = (node, options) => {
+let customToStringHandlerTwoDecimals = (node, options) => {
   if (node.type == "ConstantNode") {
     return node.value.toFixed(2);
   }
@@ -215,23 +223,38 @@ let preprocessor = (string, print = console.log) => {
     print(
       `\t= ${math
         .parse(newString)
-        .toString({ handler: customToStringHandler })}`
+        .toString({ handler: customToStringHandlerTwoDecimals })}`
     );
   return newString; // abc - 12345 - #$*%
 };
 // preprocessor("1.2 to 10.5 * 1.1 to 20 * 1 to 2.5 * 1 to 5");
 
+let customToStringHandlerLognormals = (node, options) => {
+  if (isArgLognormal(node)) {
+    let factors = getFactors(node);
+    // print(node);
+    // print(factors);
+    let ninetyPercentCI = to90PercentCI(factors[0], factors[1]);
+    return `~${ninetyPercentCI[0]} to ~${ninetyPercentCI[1]}`;
+  }
+};
+
 export function transformer(string, print = console.log) {
   string = preprocessor(string, print);
   let transformerOutput = transformerInner(string);
   let stringNew = transformerOutput.toString();
   while (stringNew != string) {
     print(
-      `\t-> ${transformerOutput.toString({ handler: customToStringHandler })}`
+      `\t-> ${transformerOutput.toString({
+        handler: customToStringHandlerTwoDecimals,
+      })}`
     );
     string = stringNew;
     transformerOutput = transformerInner(string);
     stringNew = transformerOutput.toString();
   }
-  return stringNew;
+  let stringNewAs90PercentCI = transformerOutput.toString({
+    handler: customToStringHandlerLognormals,
+  });
+  return [stringNew, stringNewAs90PercentCI];
 }