title: how to use sba(sparse bundle adjustment)
body: <p>I want to use sba to do bundle adjustment task, and I would like to use sba-1.6(<a href="http://users.ics.forth.gr/~lourakis/sba/" rel="nofollow">http://users.ics.forth.gr/~lourakis/sba/</a>). But the user manual do not tell exactly how to use it. and I am kind of confused.
  For example, I want to use this function sba_mot_levmar which has a parameter p I do not understand what it is. The problem here is that the provided examples make the rotation part in p to be 0. so that is p? 
  and after call this function, what is in p?</p>
  
  <pre><code>int sba_mot_levmar(
  const int n,   /* number of points */
  const int m,   /* number of images */
  const int mcon,
  char *vmask,  
  double *p,    /* initial parameter vector p0: (a1, ..., am).
                 * aj are the image j parameters, size m*cnp */
  const int cnp,/* number of parameters for ONE camera; e.g. 6 for Euclidean cameras */
  double *x,    
  double *covx, 
  const int mnp,
  void (*proj)(int j, int i, double *aj, double *xij, void *adata),
  
  void (*projac)(int j, int i, double *aj, double *Aij, void *adata),
  
  void *adata,      
  
  const int itmax,   
  const double opts[SBA_OPTSSZ]
  double info[SBA_INFOSZ]
  )
  </code></pre>