Merge pull request #74 from lambda-feedback/tr105-ln-instead-of-log

Fixed so that preview shows 'ln' for natural logarithm and prints bas…

Author: KarlLundengaard

app/evaluation_tests.py

@@ -32,7 +32,9 @@
     ("exp", "Bexp(x)exp(x)", "B*exp(2*x)", r"B e^{x} e^{x}"),
     ("exp2", "a+b*E^2", "a+b*exp(2)", r"a + b e^{2}"),
     ("exp3", "a+b*e^2", "a+b*exp(2)", r"a + b e^{2}"),
-    ("log", "Bexp(log(10))", "10B", r"B e^{\log{\left(10 \right)}}"),
+    ("ln", "Bexp(ln(10))", "10B", r"B e^{\ln{\left(10 \right)}}"),
+    ("log10", "B*10^(log(10,10))", "10B", r"10^{\log_{10}{\left(10 \right)}} B"),
+    ("logb", "B*b^(log(a,b))", "aB", r"B b^{\log_{b}{\left(a \right)}}"),
     ("sqrt", "Bsqrt(4)", "2B", r"\sqrt{4} B"),
     ("sign", "Bsign(1)", "B", r"B \operatorname{sign}{\left(1 \right)}"),
     ("abs", "BAbs(-2)", "2B", r"B \left|{-2}\right|"),
@@ -126,7 +128,7 @@ def test_simple_polynomial_with_input_symbols_correct(self, response, answer):
         params = {
             "strict_syntax": False,
             "symbols": {
-                "longName": {"aliases": [], "latex": "\\(\\mathrm\{longName\}\\)"}
+                "longName": {"aliases": [], "latex": r"\(\mathrm{longName}\)"}
             }
         }
         result = evaluation_function(response, answer, params)

app/expression_utilities.py

@@ -16,14 +16,32 @@
 import re
 from typing import Dict, List, TypedDict
 
+class ModifiedLatexPrinter(LatexPrinter):
+    """Modified LatexPrinter class that prints logarithms other than the natural logarithm correctly.
+    """
+    def _print_log(self, expr, exp=None):
+        if self._settings["ln_notation"] and len(expr.args) < 2:
+            log_not = r"\ln"
+        else:
+            log_not = r"\log"
+        if len(expr.args) > 1:
+            base = self._print(expr.args[1])
+            log_not = r"\log_{%s}" % base
+        tex = r"%s{\left(%s \right)}" % (log_not, self._print(expr.args[0]))
+
+        if exp is not None:
+            return r"%s^{%s}" % (tex, exp)
+        else:
+            return tex
+
 elementary_functions_names = [
     ('sin', []), ('sinc', []), ('csc', ['cosec']), ('cos', []), ('sec', []), ('tan', []), ('cot', ['cotan']),
     ('asin', ['arcsin']), ('acsc', ['arccsc', 'arccosec', 'acosec']), ('acos', ['arccos']), ('asec', ['arcsec']),
     ('atan', ['arctan']), ('acot', ['arccot', 'arccotan', 'acotan']), ('atan2', ['arctan2']),
     ('sinh', []), ('cosh', []), ('tanh', []), ('csch', ['cosech']), ('sech', []),
     ('asinh', ['arcsinh']), ('acosh', ['arccosh']), ('atanh', ['arctanh']),
     ('acsch', ['arccsch', 'arccosech']), ('asech', ['arcsech']),
-    ('exp', ['Exp']), ('E', ['e']), ('log', []),
+    ('exp', ['Exp']), ('E', ['e']), ('log', ['ln']),
     ('sqrt', []), ('sign', []), ('Abs', ['abs']), ('Max', ['max']), ('Min', ['min']), ('arg', []), ('ceiling', ['ceil']), ('floor', []),
     # Below this line should probably not be collected with elementary functions. Some like 'common operations' would be a better name
     ('summation', ['sum','Sum']), ('Derivative', ['diff']), 
@@ -453,10 +471,18 @@ def latex_symbols(symbols):
     return symbol_dict
 
 
-def sympy_to_latex(equation, symbols):
-    latex_out = LatexPrinter(
-        {"symbol_names": latex_symbols(symbols)}
-    ).doprint(equation)
+def sympy_to_latex(equation, symbols, settings=None):
+    default_settings = {
+        "symbol_names": latex_symbols(symbols),
+        "ln_notation": True,
+    }
+    if settings is None:
+        settings = default_settings
+    else:
+        for key in default_settings.keys():
+            if key not in settings.keys():
+                settings[key] = default_settings[key]
+    latex_out = ModifiedLatexPrinter(settings).doprint(equation)
     return latex_out
 
 

app/preview.py

@@ -2,7 +2,6 @@
 
 import sympy
 from latex2sympy2 import latex2sympy
-from sympy.printing.latex import LatexPrinter
 from typing_extensions import NotRequired
 
 from sympy.parsing.sympy_parser import T as parser_transformations
@@ -16,6 +15,7 @@
     substitute_input_symbols,
     SymbolDict,
     sympy_symbols,
+    sympy_to_latex,
 )
 
 from .feedback.symbolic_equal import internal as symbolic_equal_internal_messages
@@ -146,9 +146,7 @@ def preview_function(response: str, params: Params) -> Result:
         latex_out = []
         sympy_out = []
         for expression in expression_list:
-            latex_out.append(
-                LatexPrinter({"symbol_names": latex_symbols(symbols)}).doprint(expression)
-            )
+            latex_out.append(sympy_to_latex(expression, symbols))
             sympy_out.append(str(expression))
 
         if len(sympy_out) == 1: