Subroutine */
| 8550 | } /* dsyr2_ */ |
| 8551 | |
| 8552 | /* Subroutine */ int dsyr2k_(char *uplo, char *trans, integer *n, integer *k, |
| 8553 | doublereal *alpha, doublereal *a, integer *lda, doublereal *b, |
| 8554 | integer *ldb, doublereal *beta, doublereal *c__, integer *ldc) |
| 8555 | { |
| 8556 | /* System generated locals */ |
| 8557 | integer a_dim1, a_offset, b_dim1, b_offset, c_dim1, c_offset, i__1, i__2, |
| 8558 | i__3; |
| 8559 | |
| 8560 | /* Local variables */ |
| 8561 | static integer i__, j, l, info; |
| 8562 | static doublereal temp1, temp2; |
| 8563 | extern logical lsame_(char *, char *); |
| 8564 | static integer nrowa; |
| 8565 | static logical upper; |
| 8566 | extern /* Subroutine */ int xerbla_(char *, integer *); |
| 8567 | |
| 8568 | |
| 8569 | /* |
| 8570 | Purpose |
| 8571 | ======= |
| 8572 | |
| 8573 | DSYR2K performs one of the symmetric rank 2k operations |
| 8574 | |
| 8575 | C := alpha*A*B' + alpha*B*A' + beta*C, |
| 8576 | |
| 8577 | or |
| 8578 | |
| 8579 | C := alpha*A'*B + alpha*B'*A + beta*C, |
| 8580 | |
| 8581 | where alpha and beta are scalars, C is an n by n symmetric matrix |
| 8582 | and A and B are n by k matrices in the first case and k by n |
| 8583 | matrices in the second case. |
| 8584 | |
| 8585 | Arguments |
| 8586 | ========== |
| 8587 | |
| 8588 | UPLO - CHARACTER*1. |
| 8589 | On entry, UPLO specifies whether the upper or lower |
| 8590 | triangular part of the array C is to be referenced as |
| 8591 | follows: |
| 8592 | |
| 8593 | UPLO = 'U' or 'u' Only the upper triangular part of C |
| 8594 | is to be referenced. |
| 8595 | |
| 8596 | UPLO = 'L' or 'l' Only the lower triangular part of C |
| 8597 | is to be referenced. |
| 8598 | |
| 8599 | Unchanged on exit. |
| 8600 | |
| 8601 | TRANS - CHARACTER*1. |
| 8602 | On entry, TRANS specifies the operation to be performed as |
| 8603 | follows: |
| 8604 | |
| 8605 | TRANS = 'N' or 'n' C := alpha*A*B' + alpha*B*A' + |
| 8606 | beta*C. |
| 8607 | |
| 8608 | TRANS = 'T' or 't' C := alpha*A'*B + alpha*B'*A + |
| 8609 | beta*C. |