samin, damin, scamin, dzamin 

Minimum absolute value

FORMAT

  {S,D}AMIN (n, x, incx) SCAMIN (n, x, incx) DZAMIN (n, x, incx)

Function Value

  amin                real*4 |  real*8
                      The element of the vector x with the smallest absolute
                      value.
                      If n<=0, amin = 0.

Arguments

  n                   integer*4
                      On entry, the number of elements in the vector x.
                      On exit, n is unchanged.

  x                   real*4 |  real*8 |  complex*8 |  complex*16
                      On entry, a one-dimensional array X of length at least
                      (1+(n-1)*|incx|), containing the elements of the vector
                      x.
                      On exit, x is unchanged.

  incx                integer*4
                      On entry, the increment for the array X.
                      If incx > 0, vector x is stored forward in the array,
                      so that x(i) is stored in location X(1+(i-1)*incx).
                      If incx < 0, vector x is stored backward in the array,
                      so that x(i) is stored in location X(1+(n-i)*|incx|).
                      If incx = 0, only the first element is accessed.
                      On exit, incx is unchanged.

Description

  These functions determine the smallest absolute value of the elements of a
  vector x: MAX{|x(j)|, j = 1,2, ..., n}
  For complex vectors, each element x(j) is a complex number.  In this
  subprogram, the absolute value of a complex number is defined as the
  absolute value of the real part of the complex number plus the absolute
  value of the imaginary part of the complex number: |x(j)| = |a(j)| + |b(j)|
  = |(real)| + |(imaginary)|

  If incx < 0, the result is identical to using |incx|.  If incx = 0, the
  computation is a time-consuming way of setting amin = |x(1)|.

Example

  INTEGER*4 N, INCX
  REAL*4 X(400), AMIN
  INCX = 3
  N = 100
  AMIN = SAMIN(N,X,INCX)

  These FORTRAN examples show how to compute the element with the smallest
  absolute value.