Poisson SVD

• Code for Poisson SVD, also called EPCA (for Exponential PCA).
• An example of how to call p1svd.  Note that we don't expect zero error, since newp1svd constrains the first column of u to be constant; to get zero error, we could call newp1svd(x,5) instead.

  % build a random matrix whose componentwise log has low rank
  uu = randn(10,4);
  vv = randn(4,100);
  x = exp(uu*vv*.1);
  
  % decompose it using EPCA and report error
  [u,v]=newp1svd(x,4,50);
  norm(x-exp(u*v))/norm(x)
  

• Code for reconstruction of a new vector using the basis learned in an EPCA.
• An example of how to call newpproject, using the variables x and u from the above p1svd example:

  vhat = newpproject(x, u);