4.6 _JT_ storage_ blocktridiagsymmetric_ - symmetric block-tridiagonal format

• Status: NOT IMPLEMENTED
• Current value: 5
• Also requires:

  Variable	Meaning	Value
  ia(_JT_ idim_)	leading dimension	3
  ia(_JT_ nrows_)	number of rows	2
  ia(_JT_ blocksize_)	size of blocks	7
  ia(_JT_ blocks_)	number of blocks	8

• Example:
  A = $$\left(\vphantom{ \begin{array}{ccccc} \par A_1 & B_1 & & & \\ ... ... . & \\ & & . & . &B_{n-1} \\ & & &B_{n-1}& A_n \par\end{array} }\right.$$$$\begin{array}{ccccc} \par A_1 & B_1 & & & \\ B_1 & A_2 & B_2 &... ...& . & . & . & \\ & & . & . &B_{n-1} \\ & & &B_{n-1}& A_n \par\end{array}$$ $$\left.\vphantom{ \begin{array}{ccccc} \par A_1 & B_1 & & & \\ ... ... . & \\ & & . & . &B_{n-1} \\ & & &B_{n-1}& A_n \par\end{array} }\right)$$

  would be stored as:

  a = (A₁, A₂,..., A_n, B₁, B₂,..., B_{n - 1})

  Note that the number of unknowns is equal to ia(_JT_ blocksize_) *ia(_JT_ blocks_) .