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6 .TH VATAN_ 3MVEC "Dec 14, 2007" "SunOS 5.11" "Vector Math Library Functions"
8 vatan_, vatanf_ \- vector arctangent functions
12 cc [ \fIflag\fR\&.\|.\|. ] \fIfile\fR\&.\|.\|. \fB-lmvec\fR [ \fIlibrary\fR\&.\|.\|. ]
14 \fBvoid\fR \fBvatan_\fR(\fBint *\fR\fIn\fR,\fBdouble * restrict\fR \fIx\fR, \fBint *\fR\fIstridex\fR,
15 \fBdouble * restrict\fR \fIy\fR, \fBint *\fR\fIstridey\fR);
20 \fBvoid\fR \fBvatanf_\fR(\fBint *\fR\fIn\fR, \fBfloat * restrict\fR \fIx\fR, \fBint *\fR\fIstridex\fR,
21 \fBfloat * restrict\fR \fIy\fR, \fBint *\fR\fIstridey\fR);
27 These functions evaluate the function \fBatan\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.
34 Specifically, \fBvatan_\fR(\fIn\fR, \fIx\fR, \fIsx\fR, \fIy\fR, \fIsy\fR)
35 computes \fIy\fR[\fIi\fR * *\fIsy\fR] = \fBatan\fR(\fIx\fR[\fIi\fR *
36 *\fIsx\fR]) for each \fIi\fR = 0, 1, ..., *\fIn\fR - 1. The \fBvatanf_()\fR
37 function performs the same computation for single precision data.
40 These functions are not guaranteed to deliver results that are identical to the
41 results of the \fBatan\fR(3M) functions given the same arguments.
42 Non-exceptional results, however, are accurate to within a unit in the last
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.
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.
64 These functions handle special cases and exceptions in the same way as the
65 \fBatan()\fR functions when \fBc99\fR \fBMATHERREXCEPT\fR conventions are in
66 effect. See \fBatan\fR(3M) for the results for special cases.
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
80 See \fBattributes\fR(5) for descriptions of the following attributes:
89 ATTRIBUTE TYPE ATTRIBUTE VALUE
91 Interface Stability Committed
99 \fBatan\fR(3M), \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M),