Section 12: Calculating with Matrices 173

A problem using this procedure is given in the HP-15C Advanced Functions Handbook under Solving a Large System of Complex Equations.

Miscellaneous Operations Involving Matrices

Using a Matrix Element With Register Operations

If a letter key specifying a matrix is pressed after any of the following function keys, the operation is performed using the matrix element specified by the row and column numbers in R0 and R1, just as though it were a data storage register.

O*l*O{+, -, *, ÷} l{+, -,*, ÷}

eI

X

Using Matrix Descriptors in the Index Register

In certain applications, you may want to perform a programmed sequence of matrix operations using any of the matrices A through E. In this situation, the matrix operations can refer to whatever matrix descriptor is stored in the index register (RI).

If the Index register contains a matrix descriptor:Pressing %after any of the functions listed above performs the

operations using the element specified by R0 and R1 and the matrix specified in RI.

Pressing %after Oor lperforms the operation using the element specified by the row and column numbers in the Y- and X-registers and the matrix specified in RI.

*Also, in User mode the row and column numbers in R0 and R1 are incremented according to the dimensions of the specified matrix.