fix: fix zero cancelling bug in dimensional analysis

Test has been added
mgreminger · Jan 9, 2025 · c799317 · c799317
1 parent 0ba5eba
commit c799317
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Showing 3 changed files with 27 additions and 5 deletions.
diff --git a/public/dimensional_analysis.py b/public/dimensional_analysis.py
@@ -1516,10 +1516,14 @@ def replace_placeholder_funcs(expr: Expr,
                               dim_values_dict: dict[tuple[Basic,...], DimValues],
                               function_parents: list[Basic],
                               data_table_subs: DataTableSubs | None) -> Expr:
+
+    if (not is_matrix(expr)):
+        if isinstance(expr, Symbol) and expr.name == "_zero_delayed_substitution":
+            return sympify('0')
 
-    if (not is_matrix(expr)) and expr.func == function_id_wrapper:
-        function_parents.append(expr.args[0])
-        expr = cast(Expr, expr.args[1])
+        elif expr.func == function_id_wrapper:
+            function_parents.append(expr.args[0])
+            expr = cast(Expr, expr.args[1])
 
     if is_matrix(expr):
         rows = []
@@ -1736,7 +1740,7 @@ def get_sorted_statements(statements: list[Statement], custom_definition_names:
 zero_place_holder: ImplicitParameter = {
         "dimensions": [0]*9,
         "original_value": "0",
-        "si_value": "0",
+        "si_value": "_zero_delayed_substitution",
         "name": ZERO_PLACEHOLDER,
         "units": ""
     }

diff --git a/src/parser/LatexToSympy.ts b/src/parser/LatexToSympy.ts
@@ -1976,6 +1976,10 @@ export class LatexToSympy extends LatexParserVisitor<string | Statement | UnitBl
       } 
     }
 
+    if(Number(si_value) === 0) {
+      si_value = "_zero_delayed_substitution";
+    }
+
     this.implicitParams.push({
       name: newParamName,
       units: unitBlockData.units,

diff --git a/tests/test_basic.spec.mjs b/tests/test_basic.spec.mjs
@@ -761,11 +761,25 @@ test('Test function notation with exponents and units and nested functions', asy
   await page.waitForSelector('text=Updating...', {state: 'detached'});
 
   let content = await page.textContent('#result-value-0');
-  expect(parseLatexFloat(content)).toBeCloseTo(512, precision-1);  
+  expect(parseLatexFloat(content)).toBeCloseTo(512, precision);  
   content = await page.textContent('#result-units-0');
   expect(content).toBe('');
 });
 
+test('Test zero canceling bug with exponent', async () => {
+
+  await page.setLatex(0, String.raw`y=\frac{0\left\lbrack m\right\rbrack}{2^{x}}`);
+  await page.click('#add-math-cell');
+  await page.setLatex(1, String.raw`y\left(x=1\right)=`);
+
+  await page.waitForSelector('text=Updating...', {state: 'detached'});
+
+  let content = await page.textContent('#result-value-1');
+  expect(parseLatexFloat(content)).toBeCloseTo(0, precision);  
+  content = await page.textContent('#result-units-1');
+  expect(content).toBe('m');
+});
+
 
 test('Test function notation with integrals', async () => {