HP MLIB User's Guide Vol. 1 7th Ed.

216 HP MLIB User’s Guide
SGBMV/DGBMV/CGBMV/ZGBMV Matrix-vector multiply
x Array containing the vector x. The number of elements
of x and the value of lenx, the dimension of the array x,
depend on trans:
incx Increment for the array x, incx ≠ 0:
incx > 0 x is stored forward in array x; that is,
x
i
is stored in x((i−1)×incx+1).
incx < 0 x is stored backward in array x; that
is, if trans = ’N’ or ’n’, then x
i
is stored
in x((i−n)×incx+1); otherwise, x
i
is
stored in x((i−m)×incx+1).
Use incx = 1 if the vector x is stored contiguously in
array x, that is, if x
i
is stored in x(i). Refer to “BLAS
Indexing Conventions” in the introduction to
Chapter 2.
beta The scalar β.
y Array containing the vector y. The number of elements
of y and the value of leny, the dimension of the array y,
depend on trans:
Not used as input if beta = 0.
incy Increment for the array y, incy ≠ 0:
incy > 0 y is stored forward in array y; that is,
y
i
is stored in y((i−1)×incy+1).
incy < 0 y is stored backward in array y; that
is, if trans = ’N’ or ’n’, then y
i
is stored
in y((i−m)×incy+1); otherwise, y
i
is
stored in y((i−n)×incy+1).
Use incy = 1 if the vector y is stored contiguously in
array y, that is, if y
i
is stored in y(i). Refer to “BLAS
Indexing Conventions” in the introduction to
Chapter 2.
’N’ or ’n’ x has n elements lenx = (n−1)×|incx|+1
otherwise x has m elements lenx = (m−1)×|incx|+1
’N’ or ’n’ y has m elements leny = (m−1)×|incy|+1
otherwise y has n elements leny = (n−1)×|incy|+1