| 16616 | } /* slange_ */ |
| 16617 | |
| 16618 | doublereal slanst_(char *norm, integer *n, real *d__, real *e) |
| 16619 | { |
| 16620 | /* System generated locals */ |
| 16621 | integer i__1; |
| 16622 | real ret_val, r__1, r__2, r__3, r__4, r__5; |
| 16623 | |
| 16624 | /* Local variables */ |
| 16625 | static integer i__; |
| 16626 | static real sum, scale; |
| 16627 | extern logical lsame_(char *, char *); |
| 16628 | static real anorm; |
| 16629 | extern /* Subroutine */ int slassq_(integer *, real *, integer *, real *, |
| 16630 | real *); |
| 16631 | |
| 16632 | |
| 16633 | /* |
| 16634 | -- LAPACK auxiliary routine (version 3.2) -- |
| 16635 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 16636 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 16637 | November 2006 |
| 16638 | |
| 16639 | |
| 16640 | Purpose |
| 16641 | ======= |
| 16642 | |
| 16643 | SLANST returns the value of the one norm, or the Frobenius norm, or |
| 16644 | the infinity norm, or the element of largest absolute value of a |
| 16645 | real symmetric tridiagonal matrix A. |
| 16646 | |
| 16647 | Description |
| 16648 | =========== |
| 16649 | |
| 16650 | SLANST returns the value |
| 16651 | |
| 16652 | SLANST = ( max(abs(A(i,j))), NORM = 'M' or 'm' |
| 16653 | ( |
| 16654 | ( norm1(A), NORM = '1', 'O' or 'o' |
| 16655 | ( |
| 16656 | ( normI(A), NORM = 'I' or 'i' |
| 16657 | ( |
| 16658 | ( normF(A), NORM = 'F', 'f', 'E' or 'e' |
| 16659 | |
| 16660 | where norm1 denotes the one norm of a matrix (maximum column sum), |
| 16661 | normI denotes the infinity norm of a matrix (maximum row sum) and |
| 16662 | normF denotes the Frobenius norm of a matrix (square root of sum of |
| 16663 | squares). Note that max(abs(A(i,j))) is not a consistent matrix norm. |
| 16664 | |
| 16665 | Arguments |
| 16666 | ========= |
| 16667 | |
| 16668 | NORM (input) CHARACTER*1 |
| 16669 | Specifies the value to be returned in SLANST as described |
| 16670 | above. |
| 16671 | |
| 16672 | N (input) INTEGER |
| 16673 | The order of the matrix A. N >= 0. When N = 0, SLANST is |
| 16674 | set to zero. |
| 16675 | |