title: What is the equivalent of Matlab's cwt() in Python? (continuous 1-D wavelet transform)
body: <p>I want to compute the wavelet of a signal with different scales and timeshifts.</p>
  
  <p>In Matlab using the <a href="http://www.mathworks.com/help/wavelet/ref/cwt.html" rel="noreferrer"><code>cwt()</code></a> function (Continuous 1-D wavelet transform) provided in the <a href="http://www.mathworks.com/help/wavelet/index.html" rel="noreferrer">Wavelet Toolbox</a> I can specify the scale(s) I want as a parameter to cwt(), and it will return all possible timeshifts:</p>
  
  <pre><code>x = [1, 2, 3, 4];
  scales = [1, 2, 3];
  wavelet_name = 'db1';
  coefs = cwt(x,scales, wavelet_name);
  
  &gt;&gt; coefs =   
  
     -0.0000   -0.0000   -0.0000    0.0000
     -0.7071   -0.7071   -0.7071   -0.7071
     -1.1553   -1.1553   -1.1553    1.7371
  </code></pre>
  
  <p>How can I achieve that in Python?</p>
  
  <p>Here are my two attempts so far:</p>
  
  <ol>
  <li>In <a href="http://www.pybytes.com/pywavelets/" rel="noreferrer">PyWavelets</a> (Discrete Wavelet Transform in Python), I don't see how I can specify the scale parameter of the wavelet. </li>
  <li>In <a href="http://docs.scipy.org/doc/scipy-0.13.0/reference/generated/scipy.signal.cwt.html" rel="noreferrer"><code>scipy.signal.cwt</code></a>, I can't find <a href="https://stackoverflow.com/q/23730383/395857">the list of the built-in wavelet functions that I can pass to scipy.signal.cwt</a>: I want to have at least the most common wavelet functions such as sym2 and db1. (e.g. see <a href="http://www.mathworks.com/help/wavelet/ref/waveletfamilies.html" rel="noreferrer">Matlab's built-in wavelet list</a>).</li>
  </ol>