# HG changeset patch
# User Tatsuro Matsuoka <tmacchant@yahoo.co.jp>
# Date 1293008399 18000
# Node ID a7e73f903ea683d8bd722865e130818f74fce5ba
# Parent  51b6193e90bb52d30dcec0cbd17f0258c4e6577a
nonlin.txi: correct docs for using Jacobian with fsolve

diff -r 51b6193e90bb -r a7e73f903ea6 doc/ChangeLog
--- a/doc/ChangeLog	Wed Dec 22 03:53:39 2010 -0500
+++ b/doc/ChangeLog	Wed Dec 22 03:59:59 2010 -0500
@@ -1,3 +1,7 @@
+2010-12-22  Tatsuro Matsuoka  <tmacchant@yahoo.co.jp>
+
+	* nonlin.txi: Correct docs for using Jacobian with fsolve.
+
 2010-12-22  Judd Storrs <jstorrs@gmail.com>
 
 	* interpreter/expr.txi: Insert operator function docstrings.
diff -r 51b6193e90bb -r a7e73f903ea6 doc/interpreter/nonlin.txi
--- a/doc/interpreter/nonlin.txi	Wed Dec 22 03:53:39 2010 -0500
+++ b/doc/interpreter/nonlin.txi	Wed Dec 22 03:59:59 2010 -0500
@@ -68,6 +68,7 @@
 @example
 @group
 function y = f (x)
+  y = zeros (2, 1);
   y(1) = -2*x(1)^2 + 3*x(1)*x(2)   + 4*sin(x(2)) - 6;
   y(2) =  3*x(1)^2 - 2*x(1)*x(2)^2 + 3*cos(x(1)) + 4;
 endfunction
@@ -137,11 +138,17 @@
 
 @example
 @group
-function J = jacobian(x)
-  J(1,1) =  3*x(2) - 4*x(1);
-  J(1,2) =  4*cos(x(2)) + 3*x(1);
-  J(2,1) = -2*x(2)^2 - 3*sin(x(1)) + 6*x(1);
-  J(2,2) = -4*x(1)*x(2);
+function [y, jac] = f (x)
+  y = zeros (2, 1);
+  y(1) = -2*x(1)^2 + 3*x(1)*x(2)   + 4*sin(x(2)) - 6;
+  y(2) =  3*x(1)^2 - 2*x(1)*x(2)^2 + 3*cos(x(1)) + 4;
+  if (nargout == 2)
+    jac = zeros (2, 2);
+    jac(1,1) =  3*x(2) - 4*x(1);
+    jac(1,2) =  4*cos(x(2)) + 3*x(1);
+    jac(2,1) = -2*x(2)^2 - 3*sin(x(1)) + 6*x(1);
+    jac(2,2) = -4*x(1)*x(2);
+  endif
 endfunction
 @end group
 @end example
@@ -150,7 +157,7 @@
 The Jacobian can then be used with the following call to @code{fsolve}:
 
 @example
-[x, fval, info] = fsolve (@{@@f, @@jacobian@}, [1; 2]);
+[x, fval, info] = fsolve (@@f, [1; 2], optimset ("jacobian", "on"));
 @end example
 
 @noindent