150 Section 12: Calculating with MatricesOne-Matrix Operations:Sign Change, Inverse, Transpose, Norms, Determinant

 

Result inEffect on MatrixEffect on Result
Keystroke(s)Specified in

X-register

Matrix

 

X-register

 

 

 

No change.Changes sign ofNone. ‡

 

 

all elements.

 

Descriptor of

None. ‡

Inverse of
(´∕inresult matrix.

 

specified matrix.
User Mode)

 

 

§

´>4

Descriptor of

Replaced by

None. ‡

 

transpose.

transpose.

 

´>7Row norm ofNone.

None.

 

specified

 

 

 

matrix.*

 

 

´>8Frobenius or

None.

None.

 

Euclidean norm

 

 

 

of specified

 

 

 

matrix.

 

 

´>9Determinant ofNone.‡LU decomposi-

 

specified

 

tion of specified

 

matrix.

 

matrix.§

* The row norm is the largest sum of the absolute values of the elements in

 

each row of the specified matrix.

The Frobenius of Euclidean norm is the square root of the sum of the

squares of all elements in the specified matrix.

 

Unless the result matrix is the same matrix specified in the X-register.

§ If the specified matrix is a singular matrix (that is, one that doesn’t have an inverse), then the HP-15C modifies the LU form by an amount that is usually small compared to round-off error. For , the calculated inverse is the inverse of a matrix close to the original, singular matrix. (Refer to the HP-15C Advanced Functions Handbook for further information.)