Merge pull request #1205 from mathics/fixtimesinfinity

Fixtimesinfinity

Author: rocky

CHANGES.rst

@@ -26,7 +26,7 @@ Enhancements
   ``Compile[] and CompiledFunction[]``  every expression can have a compiled form,
   as a Python function.
 * ``Equal[]`` now compares complex against other numbers properly.
-
+* Improvements in handling products with infinite factors: ``0 Infinity``-> ``Indeterminate``, and ``expr Infinity``-> ``DirectedInfinite[expr]``
 
 Bug fixes
 +++++++++

mathics/builtin/arithmetic.py

@@ -34,6 +34,10 @@
     SymbolFalse,
     SymbolNull,
     SymbolTrue,
+    SymbolList,
+    SymbolInfinity,
+    SymbolDirectedInfinity,
+    SymbolComplexInfinity,
     from_python,
     from_mpmath,
 )
@@ -42,6 +46,7 @@
 from mathics.builtin.lists import _IterationFunction
 from mathics.core.convert import from_sympy, SympyExpression
 
+
 @lru_cache(maxsize=1024)
 def call_mpmath(mpmath_function, mpmath_args):
     try:
@@ -642,10 +647,10 @@ def format_outputform(self, items, evaluation):
 
     def apply(self, items, evaluation):
         "Times[items___]"
-
         items = items.numerify(evaluation).get_sequence()
         leaves = []
         numbers = []
+        infinity_factor = False
 
         prec = min_prec(*items)
         is_machine_precision = any(item.is_machine_precision() for item in items)
@@ -681,6 +686,16 @@ def apply(self, items, evaluation):
                 leaves[-1] = Expression(
                     "Power", item, Expression("Plus", Integer(1), leaves[-1].leaves[1])
                 )
+            elif item.get_head().same(SymbolDirectedInfinity):
+                infinity_factor = True
+                if len(item.leaves)>1:
+                    direction = item.leaves[0]
+                    if isinstance(direction, Number):
+                        numbers.append(direction)
+                    else:
+                        leaves.append(direction)
+            elif item.same(SymbolInfinity) or item.same(SymbolComplexInfinity):
+                infinity_factor = True
             else:
                 leaves.append(item)
 
@@ -704,6 +719,8 @@ def apply(self, items, evaluation):
         if number.same(Integer(1)):
             number = None
         elif number.is_zero:
+            if infinity_factor:
+                return Symbol("Indeterminate")
             return number
         elif number.same(Integer(-1)) and leaves and leaves[0].has_form("Plus", None):
             leaves[0] = Expression(
@@ -719,11 +736,18 @@ def apply(self, items, evaluation):
             leaves.insert(0, number)
 
         if not leaves:
+            if infinity_factor:
+                return SymbolComplexInfinity
             return Integer(1)
-        elif len(leaves) == 1:
-            return leaves[0]
+
+        if len(leaves) == 1:
+            ret = leaves[0]
         else:
-            return Expression("Times", *leaves)
+            ret = Expression("Times", *leaves)
+        if infinity_factor:
+            return Expression(SymbolDirectedInfinity, ret)
+        else:
+            return ret
 
 
 class Divide(BinaryOperator):
@@ -857,7 +881,7 @@ class Power(BinaryOperator, _MPMathFunction):
     #> (3/2+1/2I)^2
      = 2 + 3 I / 2
     #> I ^ I
-     = I ^ I
+     = -1 ^ (I / 2)
 
     #> 2 ^ 2.0
      = 4.
@@ -905,6 +929,9 @@ class Power(BinaryOperator, _MPMathFunction):
         ("", "x_ ^ y_?Negative"): (
             "HoldForm[Divide[1, #]]&[If[y==-1, HoldForm[x], HoldForm[x]^-y]]"
         ),
+        ("", "x_?Negative ^ y_"): (
+            'Infix[{HoldForm[(x)], HoldForm[y]},"^", 590, Right]'
+        ),
     }
 
     rules = {
@@ -931,6 +958,10 @@ def apply_check(self, x, y, evaluation):
                 elif py_y < 0:
                     evaluation.message("Power", "infy", Expression("Power", x, y_err))
                     return Symbol("ComplexInfinity")
+        if isinstance(x, Complex) and x.real.is_zero:
+            yhalf = Expression("Times", y, Rational(1, 2))
+            factor = self.apply(Expression("Sequence", x.imag, y), evaluation)
+            return Expression("Times", factor, Expression("Power", Integer(-1), yhalf))
 
         result = self.apply(Expression("Sequence", x, y), evaluation)
         if result is None or result != SymbolNull:
@@ -1049,6 +1080,10 @@ class DirectedInfinity(SympyFunction):
      : Indeterminate expression -Infinity + Infinity encountered.
      = Indeterminate
 
+    >> DirectedInfinity[0]
+     : Indeterminate expression 0 Infinity encountered.
+     = Indeterminate
+
     #> DirectedInfinity[1+I]+DirectedInfinity[2+I]
      = (2 / 5 + I / 5) Sqrt[5] Infinity + (1 / 2 + I / 2) Sqrt[2] Infinity
 
@@ -1057,14 +1092,15 @@ class DirectedInfinity(SympyFunction):
     """
 
     rules = {
+        "DirectedInfinity[Indeterminate]":"Indeterminate",
         "DirectedInfinity[args___] ^ -1": "0",
         "0 * DirectedInfinity[args___]": "Message[Infinity::indet, Unevaluated[0 DirectedInfinity[args]]]; Indeterminate",
         "DirectedInfinity[a_?NumericQ] /; N[Abs[a]] != 1": "DirectedInfinity[a / Abs[a]]",
         "DirectedInfinity[a_] * DirectedInfinity[b_]": "DirectedInfinity[a*b]",
         "DirectedInfinity[] * DirectedInfinity[args___]": "DirectedInfinity[]",
-        "DirectedInfinity[0]": "DirectedInfinity[]",
-        "z_?NumberQ * DirectedInfinity[]": "DirectedInfinity[]",
-        "z_?NumberQ * DirectedInfinity[a_]": "DirectedInfinity[z * a]",
+        # Rules already implemented in Times.apply
+        #        "z_?NumberQ * DirectedInfinity[]": "DirectedInfinity[]",
+        #        "z_?NumberQ * DirectedInfinity[a_]": "DirectedInfinity[z * a]",
         "DirectedInfinity[a_] + DirectedInfinity[b_] /; b == -a": (
             "Message[Infinity::indet,"
             "  Unevaluated[DirectedInfinity[a] + DirectedInfinity[b]]];"
@@ -1076,12 +1112,23 @@ class DirectedInfinity(SympyFunction):
             "Indeterminate"
         ),
         "DirectedInfinity[args___] + _?NumberQ": "DirectedInfinity[args]",
+        "DirectedInfinity[0]": (
+            "Message[Infinity::indet,"
+            "  Unevaluated[DirectedInfinity[0]]];"
+            "Indeterminate"
+        ),
+        "DirectedInfinity[0.]": (
+            "Message[Infinity::indet,"
+            "  Unevaluated[DirectedInfinity[0.]]];"
+            "Indeterminate"
+        ),
     }
 
     formats = {
         "DirectedInfinity[1]": "HoldForm[Infinity]",
         "DirectedInfinity[-1]": "HoldForm[-Infinity]",
         "DirectedInfinity[]": "HoldForm[ComplexInfinity]",
+        "DirectedInfinity[DirectedInfinity[z_]]": "DirectedInfinity[z]",
         "DirectedInfinity[z_?NumericQ]": "HoldForm[z Infinity]",
     }
 
@@ -1365,7 +1412,7 @@ def apply(self, expr, evaluation):
         sympy_expr = expr.to_sympy()
         result = _iszero(sympy_expr)
         if result is None:
-        # try expanding the expression
+            # try expanding the expression
             exprexp = Expression("ExpandAll", expr).evaluate(evaluation)
             exprexp = exprexp.to_sympy()
             result = _iszero(exprexp)

mathics/builtin/base.py

@@ -23,6 +23,8 @@
     PrecisionReal,
     String,
     Symbol,
+    SymbolTrue,
+    SymbolFalse,
     ensure_context,
     strip_context,
 )
@@ -445,6 +447,7 @@ def get_sympy_names(self) -> typing.List[str]:
             return [self.sympy_name]
         return []
 
+
 class UnaryOperator(Operator):
     def __init__(self, format_function, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -526,13 +529,12 @@ def apply(self, expr, evaluation) -> Symbol:
         "%(name)s[expr_]"
 
         if self.test(expr):
-            return Symbol("True")
+            return SymbolTrue
         else:
-            return Symbol("False")
+            return SymbolFalse
 
 
 class SympyFunction(SympyObject):
-
     def apply(self, *args):
         """
         Generic apply method that uses the class sympy_name.
@@ -583,8 +585,6 @@ def prepare_mathics(self, sympy_expr):
         return sympy_expr
 
 
-
-
 class InvalidLevelspecError(Exception):
     pass
 

mathics/core/expression.py

@@ -2014,6 +2014,10 @@ def __getnewargs__(self):
 SymbolTrue = Symbol("True")
 SymbolAborted = Symbol("$Aborted")
 SymbolInfinity = Symbol("Infinity")
+SymbolComplexInfinity = Symbol("ComplexInfinity")
+SymbolDirectedInfinity = Symbol("DirectedInfinity")
+SymbolList = Symbol("List")
+
 
 @lru_cache(maxsize=1024)
 def from_mpmath(value, prec=None):

mathics/test.py

@@ -23,6 +23,7 @@
 
 MAX_TESTS = 100000  # Number than the total number of tests
 
+logfile = None
 
 class TestOutput(Output):
     def max_stored_size(self, settings):
@@ -36,6 +37,13 @@ def max_stored_size(self, settings):
 documentation = None
 
 
+def print_and_log(*args):
+    global logfile
+    string = "".join(args)
+    print(string)
+    if logfile:
+        logfile.write(string)
+
 def compare(result, wanted):
     if result == wanted:
         return True
@@ -64,7 +72,7 @@ def test_case(test, tests, index=0, subindex=0, quiet=False, section=None):
 
     def fail(why):
         part, chapter, section = tests.part, tests.chapter, tests.section
-        print(
+        print_and_log(
             "%sTest failed: %s in %s / %s\n%s\n%s\n"
             % (sep, section, part, chapter, test, why)
         )
@@ -198,9 +206,9 @@ def test_section(sections: set, quiet=False, stop_on_failure=False):
 
     print()
     if failed > 0:
-        print("%d test%s failed." % (failed, "s" if failed != 1 else ""))
+        print_and_log("%d test%s failed." % (failed, "s" if failed != 1 else ""))
     else:
-        print("OK")
+        print_and_log("OK")
 
 
 def open_ensure_dir(f, *args, **kwargs):
@@ -265,21 +273,21 @@ def test_all(
     if failed > 0:
         print(sep)
     if count == MAX_TESTS:
-        print(
+        print_and_log(
             "%d Tests for %d built-in symbols, %d passed, %d failed, %d skipped."
             % (total, builtin_total, total - failed - skipped, failed, skipped)
         )
     else:
-        print(
+        print_and_log(
             "%d Tests, %d passed, %d failed, %d skipped."
             % (total, total - failed, failed, skipped)
         )
     if failed_symbols:
         if stop_on_failure:
-            print("(not all tests are accounted for due to --stop-on-failure)")
-        print("Failed:")
+            print_and_log("(not all tests are accounted for due to --stop-on-failure)")
+        print_and_log("Failed:")
         for part, chapter, section in sorted(failed_symbols):
-            print("  - %s in %s / %s" % (section, part, chapter))
+            print_and_log("  - %s in %s / %s" % (section, part, chapter))
 
     if generate_output and (failed == 0 or doc_even_if_error):
         print("Save XML")
@@ -341,6 +349,7 @@ def main():
 
     global definitions
     global documentation
+    global logfile
     definitions = Definitions(add_builtin=True)
     documentation = main_mathics_documentation
 
@@ -355,6 +364,9 @@ def main():
         "--sections", "-s", dest="section", metavar="SECTION", help="only test SECTION(s). "
         "You can list multiple sections by adding a comma (and no space) in between section names."
     )
+    parser.add_argument(
+        "--logfile", "-f", dest="logfilename", metavar="LOGFILENAME", help="stores the output in [logfilename]. "
+    )
     parser.add_argument(
         "--pymathics",
         "-l",
@@ -415,6 +427,9 @@ def main():
     args = parser.parse_args()
     # If a test for a specific section is called
     # just test it
+    if args.logfilename:
+        logfile = open(args.logfilename,"wt")
+
     if args.section:
         sections = set(args.section.split(","))
         if args.pymathics:  # in case the section is in a pymathics module...
@@ -446,6 +461,8 @@ def main():
     # If TeX output requested, try to build it:
     if args.tex:
         write_latex()
+    if logfile:
+        logfile.close()
 
 
 if __name__ == "__main__":