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   6 .TH vlog_ 3MVEC "14 Dec 2007" "SunOS 5.11" "Vector Math Library Functions"
   7 .SH NAME
   8 vlog_, vlogf_ \- vector logarithm functions
   9 .SH SYNOPSIS
  10 .LP
  11 .nf
  12 cc [ \fIflag\fR\&.\|.\|. ] \fIfile\fR\&.\|.\|. \fB-lmvec\fR [ \fIlibrary\fR\&.\|.\|. ]
  13 
  14 \fBvoid\fR \fBvlog_\fR(\fBint *\fR\fIn\fR, \fBdouble * restrict\fR \fIx\fR, \fBint *\fR\fIstridex\fR,
  15      \fBdouble * restrict\fR \fIy\fR, \fBint *\fR\fIstridey\fR);
  16 .fi
  17 
  18 .LP
  19 .nf
  20 \fBvoid\fR \fBvlogf_\fR(\fBint *\fR\fIn\fR, \fBfloat * restrict\fR \fIx\fR, \fBint *\fR\fIstridex\fR,
  21      \fBfloat * restrict\fR \fIy\fR, \fBint *\fR\fIstridey\fR);
  22 .fi
  23 
  24 .SH DESCRIPTION
  25 .sp
  26 .LP
  27 These functions evaluate the function \fBlog\fR(\fIx\fR) for an entire vector
  28 of values at once. The first parameter specifies the number of values to
  29 compute. Subsequent parameters specify the argument and result vectors. Each
  30 vector is described by a pointer to the first element and a stride, which is
  31 the increment between successive elements.
  32 .sp
  33 .LP
  34 Specifically, \fBvlog_\fR(\fIn\fR, \fIx\fR, \fIsx\fR, \fIy\fR, \fIsy\fR)
  35 computes \fIy\fR[\fIi\fR * *\fIsy\fR] = \fBlog\fR(\fIx\fR[\fIi\fR * *\fIsx\fR])
  36 for each \fIi\fR = 0, 1, ..., *\fIn\fR - 1. The \fBvlogf_()\fR function
  37 performs the same computation for single precision data.
  38 .sp
  39 .LP
  40 These functions are not guaranteed to deliver results that are identical to the
  41 results of the \fBlog\fR(3M) functions given the same arguments.
  42 Non-exceptional results, however, are accurate to within a unit in the last
  43 place.
  44 .SH USAGE
  45 .sp
  46 .LP
  47 The element count *\fIn\fR must be greater than zero. The strides for the
  48 argument and result arrays can be arbitrary integers, but the arrays themselves
  49 must not be the same or overlap. A zero stride effectively collapses an entire
  50 vector into a single element. A negative stride causes a vector to be accessed
  51 in descending memory order, but note that the corresponding pointer must still
  52 point to the first element of the vector to be used; if the stride is negative,
  53 this will be the highest-addressed element in memory. This convention differs
  54 from the Level 1 BLAS, in which array parameters always refer to the
  55 lowest-addressed element in memory even when negative increments are used.
  56 .sp
  57 .LP
  58 These functions assume that the default round-to-nearest rounding direction
  59 mode is in effect. On x86, these functions also assume that the default
  60 round-to-64-bit rounding precision mode is in effect. The result of calling a
  61 vector function with a non-default rounding mode in effect is undefined.
  62 .sp
  63 .LP
  64 These functions handle special cases and exceptions in the same way as the
  65 \fBlog()\fR functions when \fBc99\fR \fBMATHERREXCEPT\fR conventions are in
  66 effect. See \fBlog\fR(3M) for the results for special cases.
  67 .sp
  68 .LP
  69 An application wanting to check for exceptions should call
  70 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On
  71 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR |
  72 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been
  73 raised. The application can then examine the result or argument vectors for
  74 exceptional values. Some vector functions can raise the inexact exception even
  75 if all elements of the argument array are such that the numerical results are
  76 exact.
  77 .SH ATTRIBUTES
  78 .sp
  79 .LP
  80 See \fBattributes\fR(5) for descriptions of the following attributes:
  81 .sp
  82 
  83 .sp
  84 .TS
  85 tab() box;
  86 cw(2.75i) |cw(2.75i) 
  87 lw(2.75i) |lw(2.75i) 
  88 .
  89 ATTRIBUTE TYPEATTRIBUTE VALUE
  90 _
  91 Interface StabilityCommitted
  92 _
  93 MT-LevelMT-Safe
  94 .TE
  95 
  96 .SH SEE ALSO
  97 .sp
  98 .LP
  99 \fBlog\fR(3M), \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M),
 100 \fBattributes\fR(5)