Subroutine */
| 30903 | } /* dlasq6_ */ |
| 30904 | |
| 30905 | /* Subroutine */ int dlasr_(char *side, char *pivot, char *direct, integer *m, |
| 30906 | integer *n, doublereal *c__, doublereal *s, doublereal *a, integer * |
| 30907 | lda) |
| 30908 | { |
| 30909 | /* System generated locals */ |
| 30910 | integer a_dim1, a_offset, i__1, i__2; |
| 30911 | |
| 30912 | /* Local variables */ |
| 30913 | static integer i__, j, info; |
| 30914 | static doublereal temp; |
| 30915 | extern logical lsame_(char *, char *); |
| 30916 | static doublereal ctemp, stemp; |
| 30917 | extern /* Subroutine */ int xerbla_(char *, integer *); |
| 30918 | |
| 30919 | |
| 30920 | /* |
| 30921 | -- LAPACK auxiliary routine (version 3.2) -- |
| 30922 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 30923 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 30924 | November 2006 |
| 30925 | |
| 30926 | |
| 30927 | Purpose |
| 30928 | ======= |
| 30929 | |
| 30930 | DLASR applies a sequence of plane rotations to a real matrix A, |
| 30931 | from either the left or the right. |
| 30932 | |
| 30933 | When SIDE = 'L', the transformation takes the form |
| 30934 | |
| 30935 | A := P*A |
| 30936 | |
| 30937 | and when SIDE = 'R', the transformation takes the form |
| 30938 | |
| 30939 | A := A*P**T |
| 30940 | |
| 30941 | where P is an orthogonal matrix consisting of a sequence of z plane |
| 30942 | rotations, with z = M when SIDE = 'L' and z = N when SIDE = 'R', |
| 30943 | and P**T is the transpose of P. |
| 30944 | |
| 30945 | When DIRECT = 'F' (Forward sequence), then |
| 30946 | |
| 30947 | P = P(z-1) * ... * P(2) * P(1) |
| 30948 | |
| 30949 | and when DIRECT = 'B' (Backward sequence), then |
| 30950 | |
| 30951 | P = P(1) * P(2) * ... * P(z-1) |
| 30952 | |
| 30953 | where P(k) is a plane rotation matrix defined by the 2-by-2 rotation |
| 30954 | |
| 30955 | R(k) = ( c(k) s(k) ) |
| 30956 | = ( -s(k) c(k) ). |
| 30957 | |
| 30958 | When PIVOT = 'V' (Variable pivot), the rotation is performed |
| 30959 | for the plane (k,k+1), i.e., P(k) has the form |
| 30960 | |
| 30961 | P(k) = ( 1 ) |
| 30962 | ( ... ) |