HP 3000 Manuals

HP Business BASIC/XL Reference Manual

INV 

The INV function returns an array that is the inverse of a specified
array.  Both arrays must be of the same floating-point type.  HP Business
BASIC/XL converts a DECIMAL or SHORT DECIMAL array to REAL before
computing the inverse.

This function has the form

       MAT num_array1 = INV(num_array2)

where num_array1 is the inverse of num_array2.  Num_array1 and num_array2 
are both dimensioned (m,m) MUL(num_array1,num_array2) is an identity
matrix.  An identity matrix is a square matrix in which each element on
the upper-left to lower-right diagonal is one and all others are zero.
For example:

        1 0 0
        0 1 0
        0 0 1

The function is used in the MAT = statement, with two dimensional arrays.

Syntax 

INV(array)

Parameters 

array            Structured collection of variables of the same type.
                 The structure is determined when the array is declared.

Examples 

     10 DIM A(3,3),B(3,3)
     .
     .
     .
     50 MAT A = INV(B)

If B is

     1 2
     3 4

then A is

     -2    1
     1.5 -0.5

MPE/iX 5.0 Documentation