Fix to issue #1052: algebraic equivalence with inf.

stack/maxima/assessment.mac

@@ -991,6 +991,8 @@ numerical_not_alg_equiv(p1, p2):= block([pvars, pval, lv, sz, pnum, stack_mtell_
   if is(pval = []) then (print("STACK: ignore previous error. (2)"), return(false)),
   /* User functions without a function rule cannot be evaluated numerically */
   if recurse_userfunctionp(first(pval)) then return(false),
+  /* If we have no variables, and not a number, then bail here. */
+  if is(emptyp(lv)) and not(numberp(first(pval))) then return(false),
   pval:errcatch(ev(is(abs(first(pval)) > 1/10000), simp)),
   if is(pval = []) then (print("STACK: ignore previous error. (3)"), return(false)),
   if first(pval) then return(true),

tests/fixtures/answertestfixtures.class.php

@@ -104,6 +104,7 @@ class stack_answertest_test_data {
         array('AlgEquiv', '', 'inf', '-inf', 0, '', ''),
         array('AlgEquiv', '', '2*inf', 'inf', 0, '', ''),
         array('AlgEquiv', '', '0*inf', '0', 1, '', ''),
+        array('AlgEquiv', '', 'exp(-%i)', 'inf', 0, '', ''),
 
         array('AlgEquiv', '', 'x^(1/2)', 'sqrt(x)', 1, '', 'Powers and roots'),
         array('AlgEquiv', '', 'x', 'sqrt(x^2)', 0, '', ''),