# HG changeset patch
# User Nicholas R. Jankowski <jankowski.nicholas@gmail.com>
# Date 1652108913 14400
# Node ID 347fd06535083254ba134ab70d45297fedc8b1b9
# Parent  6b2e5f8f306bca8dbcc9d7d6ccbda2eea4313c3b
quadcc: Add a warning if error tolerance is not met (bug #62412)

* quadcc.cc (Fquadcc): Add a warning message that triggers if absolute or
relative tolerance has not been met AND an error output has not been requested.
Define nargout variable for error conditional calculation.  Update documentation
to explain new behavior.  Add BIST test for bug #62412.  Adjust tolerance of
BIST tests so they do not emit warning under default 'test quadcc' usage.
Change BIST test using inline function not to emit a warning about using an
inline function.

diff -r 6b2e5f8f306b -r 347fd0653508 libinterp/corefcn/quadcc.cc
--- a/libinterp/corefcn/quadcc.cc	Sat May 07 15:17:08 2022 -0700
+++ b/libinterp/corefcn/quadcc.cc	Mon May 09 11:08:33 2022 -0400
@@ -1488,7 +1488,7 @@
 
 // The actual integration routine.
 
-DEFMETHOD (quadcc, interp, args, ,
+DEFMETHOD (quadcc, interp, args, nargout,
            doc: /* -*- texinfo -*-
 @deftypefn  {} {@var{q} =} quadcc (@var{f}, @var{a}, @var{b})
 @deftypefnx {} {@var{q} =} quadcc (@var{f}, @var{a}, @var{b}, @var{tol})
@@ -1537,8 +1537,11 @@
 @var{nr_points} is the number of points at which the integrand was evaluated.
 
 If the adaptive integration did not converge, the value of @var{err} will be
-larger than the requested tolerance.  Therefore, it is recommended to verify
-this value for difficult integrands.
+larger than the requested tolerance.  If only a single output is requested then
+a warning will be emitted when the requested tolerance is not met.  If the
+second output @var{err} is requested then no warning is issued and it is the
+responsibility of the programmer to inspect and determine whether the results
+are satisfactory.
 
 @code{quadcc} is capable of dealing with non-numeric values of the integrand
 such as @code{NaN} or @code{Inf}.  If the integral diverges, and @code{quadcc}
@@ -2204,6 +2207,9 @@
     }
 #endif
 
+ if (nargout < 2 && err > std::max (abstol, reltol * std::abs (igral)))
+    warning ("quadcc: Error tolerance not met.  Estimated error: %g\n", err);
+
   if (issingle)
     return ovl (static_cast<float> (igral), err, neval);
   else
@@ -2212,14 +2218,16 @@
 
 /*
 %!assert (quadcc (@sin, -pi, pi), 0, 1e-10)
-%!assert (quadcc (inline ("sin"), -pi, pi), 0, 1e-10)
+%!test
+%! warning ("off", "Octave:legacy-function", "local");
+%! assert (quadcc (inline ("sin"), -pi, pi), 0, 1e-10);
 %!assert (quadcc ("sin", -pi, pi), 0, 1e-10)
 
 %!assert (quadcc (@sin, -pi, 0), -2, 1e-10)
 %!assert (quadcc (@sin, 0, pi), 2, 1e-10)
 %!assert (quadcc (@(x) 1./sqrt (x), 0, 1), 2, -1e-6)
 %!assert (quadcc (@(x) 1./(sqrt (x).*(x+1)), 0, Inf), pi, -1e-6)
-%!assert (quadcc (@(x) 1./(sqrt (x).*(x+1)), 0, Inf, [0, 1e-8]), pi, -1e-8)
+%!assert (quadcc (@(x) 1./(sqrt (x).*(x+1)), 0, Inf, [0, 2e-7]), pi, -2e-7)
 
 %!assert (quadcc (@(x) exp (-x .^ 2), -Inf, Inf), sqrt (pi), 1e-10)
 %!assert (quadcc (@(x) exp (-x .^ 2), -Inf, 0), sqrt (pi)/2, 1e-10)
@@ -2243,6 +2251,12 @@
 %! assert (class (quadcc (@sin, 0, single (1))), "single");
 %! assert (class (quadcc (@sin, single (0), single (1))), "single");
 
+%!test<62412>
+%! f = @(t) -1 ./ t.^1.1;
+%! fail ("quadcc (f, 1, Inf)", "warning", "Error tolerance not met");
+%! [q, err] = quadcc (f, 1, Inf);
+%! assert (err > 1);
+
 ## Test input validation
 %!error quadcc ()
 %!error quadcc (@sin)