## bbdbltoeplitz

This function is not yet fully documented. This is a transcript of
the text-formatted help.

bbdbltoeplitz Create an operator for a doubly Toeplitz matrix
A matrix, BB, is doubly Toeplitz if it can be written in the form:
BB=[ U0, U1, U2, ...
L1, U0, U1, ...
L2, L1, L2, ...
............... ]
where U0,U1,... and L1,L2,... are Toeplitz matrices.
In words, a doubly Toeplitz matrix is a block Toeplitz matrix with
Toeplitz blocks. Is is also known as "Toeplitz-Block Toeplitz".
Syntax:
BB=bbdbltoeplitz(RU)
BB=bbdbltoeplitz(CU,RU)
BB=bbdbltoeplitz(CU,RU,CL,RL)
BB=bbdbltoeplitz(CU,RU,[],[])
RU contains the first rows in U0,U1,..., while CU contain the columns:
CU=[U0(:,1) , U1(:,1) , U2(:,1) , ...]
RU=[U0(1,:) ; U1(1,:) ; U2(1,:) ; ...]
If CU is unspecified, the blocks are assumed to be Hermitian:
U0=U0', U1=U1', etc.
CL and RL contain the first columns and rows of L1,L2,...:
CL=[L1(:,1) , L2(:,1) , ...]
RL=[L1(1,:) ; L2(1,:) ; ...]
If CL and RL are unspecified, BB will be block-Hermitian:
L1=U1', L2=U2', etc.
If CL and RL are empty matrices, BB consist of a single block row:
BB=[U0, U1, ... ]
NOTE: The first element in the column and row in each block must be
the same.
See also bbtoeplitz, .

bbcountstatbbdiag