enable numerical comparison of vecs

Author: dqnykamp

build/math-expressions.js

@@ -3,7 +3,7 @@ import { operators } from './variables';
 import { functions } from './variables';
 import { normalize_function_names, normalize_applied_functions, subscripts_to_strings } from './normalization';
 
-var analytic_operators = ['+', '-', '*', '/', '^', 'tuple', 'vector', 'altvector', 'list', 'array', 'matrix', 'interval'];
+var analytic_operators = ['+', '-', '*', '/', '^', 'tuple', 'vector', 'altvector', 'list', 'array', 'matrix', 'interval', 'vec'];
 var non_analytic_functions = ["abs", "sign", 'arg'];
 
 var relation_operators = ['=', 'le', 'ge', '<', '>'];

build/math-expressions_umd.js

@@ -127,6 +127,7 @@ export const equals = function ({ expr, other, randomBindings,
 }
 
 
+
 const component_equals = function ({ expr, other, randomBindings,
   expr_context, other_context,
   allow_proportional = false, require_positive_proportion = false,
@@ -165,8 +166,12 @@ const component_equals = function ({ expr, other, randomBindings,
   // for functions that didn't get exponents moved outside
   // rename function with simple exponents as a single string
   // so that f^2(x) will be treated as a single function and compare equal another instance of f^2(x)
-  expr = expr.context.fromAst(rename_functions_with_exponents(expr.tree));
-  other = other.context.fromAst(rename_functions_with_exponents(other.tree));
+  let exprTree = rename_functions_with_exponents(expr.tree);
+  let otherTree = rename_functions_with_exponents(other.tree);
+
+  // rename vec to single string
+  expr = expr_context.fromAst(rename_vecs(exprTree));
+  other = other_context.fromAst(rename_vecs(otherTree));
 
   // Get set of variables mentioned in at least one of the two expressions
   var variables = [...new Set([...expr.variables(), ...other.variables()])];
@@ -692,4 +697,20 @@ function rename_functions_with_exponents(tree) {
 
   return [operator, ...operands.map(rename_functions_with_exponents)];
 
-}
+}
+
+
+function rename_vecs(tree) {
+  if (!Array.isArray(tree)) {
+    return tree;
+  }
+
+  let operator = tree[0];
+  let operands = tree.slice(1);
+
+  if (operator === "vec" && operands.length === 1) {
+    return '__vec_' + astToText.convert(operands[0])
+  } else {
+    return [operator, ...operands.map(rename_vecs)]
+  }
+}

lib/expression/analytic.js

@@ -1,7 +1,7 @@
 {
   "name": "math-expressions",
   "description": "Perform basic equality testing and symbolic computations on mathematical expressions involving transcendental functions",
-  "version": "2.0.0-alpha56",
+  "version": "2.0.0-alpha57",
   "author": {
     "name": "Jim Fowler",
     "email": "[email protected]",

lib/expression/equality/numerical.js

@@ -392,6 +392,8 @@ describe("expression", function () {
     ['A ⊆ B', 'B ⊇ A'],
     ['A ⊄ B', 'B ⊅ A'],
     ['A ⊈ B', 'B ⊉ A'],
+    ['vec(x)+vec(x)', '2vec(x)'],
+    ['sin^2(vec(x)*vec(y)) + cos^2(vec(x)*vec(y))', '1'],
   ];
 
   _.each(equivalences, function (equiv) {