| SSYR2K/DSYR2K/CHER2K/CSYR2K/ZHER2K/ZSYR2K | ||
| k | Number of rows or columns in matrices A and B, | |
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| depending on trans; refer to the description of a for | |
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| details. k ≥ 0; if k = 0, the subprograms do not reference | |
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| a or b. |
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| alpha | The scalar α. If alpha = 0, the subprograms compute | |
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| C ← βC without referencing a or b. | |
| a | Array containing the matrix A, whose size is indicated | |
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| by trans: |
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| ’N’ or ’n’ | A is |
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| otherwise | A is |
| lda | The leading dimension of array a as declared in the | |
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| calling program unit, with lda ≥ max (the number of | |
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| rows of A,1). |
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| b | Array containing matrix B, which is the same size as | |
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| matrix A. Refer to the description of a for details. | |
| ldb | The leading dimension of array b as declared in the | |
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| calling program unit, with ldb ≥ max (the number of | |
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| rows of B,1). |
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| beta | The scalar β. |
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| c | Array whose upper or lower triangle, as specified by | |
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| uplo, contains the upper or lower triangle of the | |
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| symmetric or Hermitian matrix C. Not used as input if | |
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| beta = 0. |
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| ldc | The leading dimension of array c as declared in the | |
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| calling program unit, with ldc ≥ max(n,1). | |
Output | c | The upper or lower triangle of the updated matrix C, as | |
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| specified by uplo, replaces the upper or lower triangle | |
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| of the input, respectively. The other triangle of c is | |
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| unchanged. |
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Notes These subprograms conform to specifications of the Level 3 BLAS.
If an error in the arguments is detected, the subprograms call error handler XERBLA, which writes an error message onto the standard error file and terminates execution. The standard version of XERBLA (refer to the end of this chapter) can be replaced with a
Chapter 3 Basic Matrix Operations 287