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Vector Math Library Functions                      vz_abs_(3MVEC)



NAME
     vz_abs_, vc_abs_ - vector complex absolute value functions

SYNOPSIS
     cc [ flag... ] file... -lmvec [ library... ]

     void vz_abs_(int *n, double complex * restrict z,
          int *stridez, double * restrict y, int *stridey);


     void vc_abs_(int *n, float complex * restrict z,
          int *stridez, float * restrict y, int *stridey);


DESCRIPTION
     These functions compute the magnitude (or modulus) | z | for
     an  entire  vector  of  values  at once. The first parameter
     specifies the number of values to compute. Subsequent param-
     eters  specify  the argument and result vectors. Each vector
     is described by a pointer to the first element and a stride,
     which is the increment between successive elements.


     Specifically, vz_abs_(n, z, sz, y, sy) computes y[i * *sy] =
     |  z[i  *  *sz]  |  for  each  i  =  0,  1, ..., *n - 1. The
     vc_abs_() function performs the same computation for  single
     precision data.


     These functions are not guaranteed to deliver  results  that
     are identical to the results of the cabs(3M) functions given
     the same arguments. Non-exceptional  results,  however,  are
     accurate to within a unit in the last place.

USAGE
     The element count *n must be greater than zero. The  strides
     for   the  argument  and  result  arrays  can  be  arbitrary
     integers, but the arrays themselves must not be the same  or
     overlap.  A zero stride effectively collapses an entire vec-
     tor into a single element. A negative stride causes a vector
     to be accessed in descending memory order, but note that the
     corresponding pointer must still point to the first  element
     of  the  vector  to be used; if the stride is negative, this
     will be the highest-addressed element in memory.  This  con-
     vention differs from the Level 1 BLAS, in which array param-
     eters always refer to the lowest-addressed element in memory
     even when negative increments are used.


     These functions assume  that  the  default  round-to-nearest
     rounding  direction  mode  is in effect. On x86, these func-
     tions also assume that the default round-to-64-bit  rounding



SunOS 5.11          Last change: 14 Dec 2007                    1






Vector Math Library Functions                      vz_abs_(3MVEC)



     precision  mode is in effect. The result of calling a vector
     function with a non-default rounding mode in effect is unde-
     fined.


     These functions handle special cases and exceptions  in  the
     spirit of IEEE 754. See cabs(3M) for the results for special
     cases.


     An application wanting to check for exceptions  should  call
     feclearexcept(FE_ALL_EXCEPT) before calling these functions.
     On  return,  if  fetestexcept(FE_INVALID  |  FE_DIVBYZERO  |
     FE_OVERFLOW  |  FE_UNDERFLOW)  is non-zero, an exception has
     been raised. The application can then examine the result  or
     argument  vectors  for exceptional values. Some vector func-
     tions can raise the inexact exception even if  all  elements
     of  the  argument  array are such that the numerical results
     are exact.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     cabs(3M), feclearexcept(3M), fetestexcept(3M), attributes(5)


















SunOS 5.11          Last change: 14 Dec 2007                    2