16.4.1.7 Matrix Exponentiation Operator **

The result of A**B is defined as follows when A is a square matrix and B is an integer scalar:

• For B > 0, A**B is A*…*A, where there are B ‘A’s. (PSPP implements this efficiently for large B, using exponentiation by squaring.)
• For B < 0, A**B is INV(A**(-B)).
• For B = 0, A**B is the identity matrix.

PSPP reports an error if A is not square or B is not an integer.

Examples:

{2, 5; 1, 4}**3	⇒	{48, 165; 33, 114}
{2, 5; 1, 4}**0	⇒	{1, 0; 0, 1}
10*{4, 7; 2, 6}**-1	⇒	{6, -7; -2, 4}