擅长:python、mysql、java
<p>第一件事:</p>
<pre class="lang-py prettyprint-override"><code>x1, x2 = x # unpack your coord tuple
</code></pre>
<p>第二:</p>
<pre class="lang-py prettyprint-override"><code>gradx2= w2 + w1 * x1 ** 2 # or gradx2= w2 + w1 * x1 * x1
</code></pre>
<p>在python中,{<cd1>}是按位异或。求幂是<code>**</code></p>