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Up: <a rel="up" accesskey="u" href="Zero-finders.html#Zero-finders">Zero finders</a>
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<h3 class="section">3.1 A vectorized version of fzero</h3>
<p><a name="index-vfzero-70"></a>
<!-- vfzero ../inst/vfzero.m -->
<a name="XREFvfzero"></a>
<div class="defun">
— Function File: <b>vfzero</b> (<var>fun, x0</var>)<var><a name="index-vfzero-71"></a></var><br>
— Function File: <b>vfzero</b> (<var>fun, x0, options</var>)<var><a name="index-vfzero-72"></a></var><br>
— Function File: [<var>x</var>, <var>fval</var>, <var>info</var>, <var>output</var>] = <b>vfzero</b> (<var><small class="dots">...</small></var>)<var><a name="index-vfzero-73"></a></var><br>
<blockquote><p>A variant of <code>fzero</code>. Finds a zero of a vector-valued
multivariate function where each output element only depends on the
input element with the same index (so the Jacobian is diagonal).
<p><var>fun</var> should be a handle or name of a function returning a column
vector. <var>x0</var> should be a two-column matrix, each row specifying
two points which bracket a zero of the respective output element of
<var>fun</var>.
<p>If <var>x0</var> is a single-column matrix then several nearby and distant
values are probed in an attempt to obtain a valid bracketing. If
this is not successful, the function fails. <var>options</var> is a
structure specifying additional options. Currently, <code>vfzero</code>
recognizes these options: <code>"FunValCheck"</code>, <code>"OutputFcn"</code>,
<code>"TolX"</code>, <code>"MaxIter"</code>, <code>"MaxFunEvals"</code>. For a
description of these options, see optimset.
<p>On exit, the function returns <var>x</var>, the approximate zero and
<var>fval</var>, the function value thereof. <var>info</var> is a column vector
of exit flags that can have these values:
<ul>
<li>1 The algorithm converged to a solution.
<li>0 Maximum number of iterations or function evaluations has been
reached.
<li>-1 The algorithm has been terminated from user output function.
<li>-5 The algorithm may have converged to a singular point.
</ul>
<p><var>output</var> is a structure containing runtime information about the
<code>fzero</code> algorithm. Fields in the structure are:
<ul>
<li>iterations Number of iterations through loop.
<li>nfev Number of function evaluations.
<li>bracketx A two-column matrix with the final bracketing of the
zero along the x-axis.
<li>brackety A two-column matrix with the final bracketing of the
zero along the y-axis.
</ul>
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