DetMatArray - Evaluate determinants for an array of matrices.
   
   USAGE:

   determ = DetMatArray(marray)

   INPUT:

   marray is n x n x l, 
          an array of l n x n matrices

   OUTPUT:

   determ is 1 x l, 
          the determinant of each matrix

 InvMatArray - Inverses for an array of matrices.
   
   USAGE:

   minv = InvMatArray(marray)

   INPUT:

   marray is n x n x l, 
          an array of n x n matrices

   OUTPUT:

   minv is n x n x l, 
        the inverse of each matrix

 MultMatArray - Multiply arrays of matrices.
   
   USAGE:

   prod = MultMatArray(ma1, ma2)

   INPUT:

   ma1 is m x n x l, 
       an array of m x n matrices
   ma2 is n x k x l, 
       an array of n x k matrices
  
   OUTPUT:

   prod is m x k x l, 
        the array of matrix products

 SparseOfMatArray - Sparse matrix from array of matrices.
   
   USAGE:

   smat = SparseOfMatArray(marray)

   INPUT:

   marray is m x n x l, 
          an array of m x n matrices

   OUTPUT:

   smat is l*m x l*n , (sparse)
        the sparse matrix form of the block matrix `marray'