title: Continuous wavelet transform in matlab
body: <p>I'am trying to compute CWT(continuous wavelet transform) of a 1-D signal using the command cwt it takes 3 input arguments</p>
  
  <ol>
  <li><strong>x</strong>- the input 1-D dignal.</li>
  <li><strong>scales</strong>- scales is a 1-D vector with positive elements.</li>
  <li><strong>wavename</strong>- it is the wavelet name which are inbuilt in matlab.</li>
  </ol>
  
  <p>it returns a matrix having no. of rows equal to the length of scale vector. No. of columns equal to the length of input vector x.</p>
  
  <p>now, I want a plot of log scale versus the coefficient plot bur while taking log scale I'am ending up getting a zero. and hence the cwt command is not responding(i.e.) it is giving an error message following is the small code.</p>
  
  <pre><code>clc;clear all 
  load vonkoch
  vonkoch=vonkoch(1:510); 
  len = length(vonkoch);
  scale=0.01:0.01:1;logscale=log(scale);
  cw1 = cwt(vonkoch,scale,'mexh','plot'); 
  title('Continuous Transform, absolute coefficients.') 
  ylabel('Scale')
  [cw1,sc] = cwt(vonkoch,scale,'mexh','scal');
  title('Scalogram') 
  ylabel('Scale') 
  </code></pre>
  
  <p>and the error message is</p>
  
  <pre><code>Error using cwt (line 74)
  
  Invalid Value for Scales !
  
  Error in exmp1 (line 6)
  
  cw1 = cwt(vonkoch,logscale,'mexh','plot');
  </code></pre>
  
  <p>Kindly suggest what I can do to avoid such a problem or is there any other command that can do the trick?</p>