--- a/libinterp/corefcn/qr.cc	Fri Apr 08 17:44:26 2022 -0400
+++ b/libinterp/corefcn/qr.cc	Sat Apr 09 14:52:25 2022 -0700
@@ -116,6 +116,7 @@
 @deftypefnx {} {@var{X} =} qr (@var{A}, @var{B}) # sparse A
 @deftypefnx {} {[@var{C}, @var{R}] =} qr (@var{A}, @var{B})
 @deftypefnx {} {[@dots{}] =} qr (@dots{}, 0)
+@deftypefnx {} {[@dots{}] =} qr (@dots{}, "econ")
 @deftypefnx {} {[@dots{}] =} qr (@dots{}, "vector")
 @deftypefnx {} {[@dots{}] =} qr (@dots{}, "matrix")
 @cindex QR factorization
@@ -270,14 +271,14 @@
 The default, however, is to return a permutation matrix and this may be
 explicitly specified by using a final argument of @qcode{"matrix"}.
 
-If the final argument is the scalar 0 an @qcode{"economy"} factorization is
-returned.  If the original matrix @var{A} has size MxN and M > N, then the
-@qcode{"economy"} factorization will calculate just N rows in @var{R} and N
-columns in @var{Q} and omit the zeros in @var{R}.  If M @leq{} N, there is no
-difference between the economy and standard factorizations.  When calculating
-an @qcode{"economy"} factorization and @var{A} is dense, the output @var{P} is
-always a vector rather than a matrix.  If @var{A} is sparse, output
-@var{P} is a sparse permutation matrix.
+If the final argument is the scalar 0 or the string @qcode{"econ"}, an
+economy factorization is returned.  If the original matrix @var{A} has size
+MxN and M > N, then the economy factorization will calculate just N rows in
+@var{R} and N columns in @var{Q} and omit the zeros in @var{R}.  If M @leq{}
+N, there is no difference between the economy and standard factorizations.
+When calculating an economy factorization and @var{A} is dense, the output
+@var{P} is always a vector rather than a matrix.  If @var{A} is sparse,
+output @var{P} is a sparse permutation matrix.
 
 Background: The QR factorization has applications in the solution of least
 squares problems
@@ -344,9 +345,14 @@
           std::string str = args(nargin-1).string_value ();
           if (str == "vector")
             vector_p = true;
+          else if (str == "econ")
+            {
+              economy = true;
+              have_b = (nargin > 2);
+            }
           else if (str != "matrix")
-            error ("qr: type for P must be 'matrix' or 'vector', not %s",
-                   str.c_str ());
+            error ("qr: option string must be 'econ' or 'matrix' or " \
+                   "'vector', not \"%s\"", str.c_str ());
           have_b = (nargin > 2);
         }
       else if (! args(nargin-1).is_matrix_type ())
@@ -704,45 +710,55 @@
 %!
 %! [q, r] = qr (a);
 %! [qe, re] = qr (a, 0);
+%! [qe2, re2] = qr (a, "econ");
 %!
 %! assert (q * r, a, sqrt (eps));
 %! assert (qe * re, a, sqrt (eps));
+%! assert (qe2 * re2, a, sqrt (eps));
 
 %!test
 %! a = [0, 2, 1; 2, 1, 2];
 %!
 %! [q, r] = qr (a);
 %! [qe, re] = qr (a, 0);
+%! [qe2, re2] = qr (a, "econ");
 %!
 %! assert (q * r, a, sqrt (eps));
 %! assert (qe * re, a, sqrt (eps));
+%! assert (qe2 * re2, a, sqrt (eps));
 
 %!test
 %! a = [0, 2, 1; 2, 1, 2];
 %!
 %! [q, r, p] = qr (a);  # FIXME: not giving right dimensions.
 %! [qe, re, pe] = qr (a, 0);
+%! [qe2, re2, pe2] = qr (a, "econ");
 %!
 %! assert (q * r, a * p, sqrt (eps));
 %! assert (qe * re, a(:, pe), sqrt (eps));
+%! assert (qe2 * re2, a(:, pe2), sqrt (eps));
 
 %!test
 %! a = [0, 2; 2, 1; 1, 2];
 %!
 %! [q, r] = qr (a);
 %! [qe, re] = qr (a, 0);
+%! [qe2, re2] = qr (a, "econ");
 %!
 %! assert (q * r, a, sqrt (eps));
 %! assert (qe * re, a, sqrt (eps));
+%! assert (qe2 * re2, a, sqrt (eps));
 
 %!test
 %! a = [0, 2; 2, 1; 1, 2];
 %!
 %! [q, r, p] = qr (a);
 %! [qe, re, pe] = qr (a, 0);
+%! [qe2, re2, pe2] = qr (a, "econ");
 %!
 %! assert (q * r, a * p, sqrt (eps));
 %! assert (qe * re, a(:, pe), sqrt (eps));
+%! assert (qe2 * re2, a(:, pe2), sqrt (eps));
 
 %!test
 %! a = [0, 2, 1; 2, 1, 2; 3, 1, 2];
@@ -791,6 +807,8 @@
 
 %!error qr ()
 %!error qr ([1, 2; 3, 4], 0, 2)
+%!error <option string must be .*, not "foo"> qr (magic (3), "foo")
+%!error <option string must be .*, not "foo"> qr (magic (3), rand (3, 1), "foo")
 %!error <too many output arguments for dense A with B>
 %! [q, r, p] = qr (rand (3, 2), rand (3, 1));
 %!error <too many output arguments for dense A with B>