The FORTRAN level-2 BLAS call for this operation is
Here is replaced by S, D, C, or Z to indicate the datatype of the data (single, double, complex, double precision complex). Parameter UPLO indicates whether A is lower (UPLO = "Lower") or upper (UPLO = "Upper") triangular. Parameter TRANS indicates if A is to be transposed as part of the operation (TRANS = "No transpose", "Transpose", or "Conjugate transpose"). Parameter DIAG indicates if the diagonal of A is to be taken to equal the identity matrix (DIAG = "Unit" and or ) or the values in the matrix (DIAG = "Non unit" and A = U or A = L ). Parameter N holds the matrix dimension n . Parameters A and X equal the addresses of where matrix A and vector x start in memory. The leading dimensions of the matrix is given in LDA and the strides for vector in INCX.
SUBROUTINE TRSV ( UPLO, TRANS, DIAG, N, A, LDA, X, INCX )