Maximum of magnitudes

SAMAX/DAMAX/IAMAX/SCAMAX/DZAMAX

 

INTEGER*4

n, incx

 

REAL*8

s, DZAMAX

 

COMPLEX*16

x(lenx)

 

s = DZAMAX(n, x, incx)

 

VECLIB8:

 

 

INTEGER*8

n, incx

 

REAL*4

s, SAMAX, x(lenx)

 

s = SAMAX(n, x, incx)

 

INTEGER*8

n, incx

 

REAL*8

s, DAMAX, x(lenx)

 

s = DAMAX(n, x, incx)

 

INTEGER*8

n, incx, s, IAMAX, x(lenx)

 

s = IAMAX(n, x, incx)

 

INTEGER*8

n, incx

 

REAL*4

s, SCAMAX

 

COMPLEX*8

x(lenx)

 

s = SCAMAX(n, x, incx)

 

INTEGER*8

n, incx

 

REAL*8

s, DZAMAX

 

COMPLEX*16

x(lenx)

 

s = DZAMAX(n, x, incx)

Input

n

Number of elements of vector x to be used. If n ≤ 0, the

 

 

subprograms do not reference x.

 

x

Array of length lenx = (n−1)⋅incx+1 containing the

 

 

n-vector x.

 

incx

Increment for the array x. x is stored forward in array x

 

 

with increment incx; that is, xi is stored in

 

 

x((i−1)⋅incx+1).

 

 

Use incx = 1 if the vector x is stored contiguously in

 

 

array x; that is, if xi is stored in x(i). Refer to “BLAS

 

 

Indexing Conventions” in the introduction to this

 

 

chapter.

Output

s

If n ≤ 0, then s = 0. Otherwise, s is the maximum of the

 

 

magnitudes of the elements of x.

Chapter 2 Basic Vector Operations 57