1vcospi_(3MVEC) Vector Math Library Functions vcospi_(3MVEC)
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6 vcospi_, vcospif_ - vector cospi functions
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9 cc [ flag... ] file... -lmvec [ library... ]
10 void vcospi_(int *n, double * restrict x, int *stridex,
12 double * restrict y, int *stridey);
13 void vcosfpi_(int *n, float * restrict x, int *stridex,
16 float * restrict y, int *stridey);
17
20 These functions evaluate the function cospi(x), defined by cospi(x) =
21 cos(pi * x), for an entire vector of values at once. The first parame‐
22 ter specifies the number of values to compute. Subsequent parameters
23 specify the argument and result vectors. Each vector is described by a
24 pointer to the first element and a stride, which is the increment
25 between successive elements.
26 Specifically, vcospi_(n, x, sx, y, sy) computes y[i * *sy] = cospi(x[i
29 * *sx]) for each i = 0, 1, ..., *n - 1. The vcospif_() function per‐
30 forms the same computation for single precision data.
31 Non-exceptional results are accurate to within a unit in the last
34 place.
35
37 The element count *n must be greater than zero. The strides for the
38 argument and result arrays can be arbitrary integers, but the arrays
39 themselves must not be the same or overlap. A zero stride effectively
40 collapses an entire vector into a single element. A negative stride
41 causes a vector to be accessed in descending memory order, but note
42 that the corresponding pointer must still point to the first element of
43 the vector to be used; if the stride is negative, this will be the
44 highest-addressed element in memory. This convention differs from the
45 Level 1 BLAS, in which array parameters always refer to the lowest-
46 addressed element in memory even when negative increments are used.
47 These functions assume that the default round-to-nearest rounding
50 direction mode is in effect. On x86, these functions also assume that
51 the default round-to-64-bit rounding precision mode is in effect. The
52 result of calling a vector function with a non-default rounding mode in
53 effect is undefined.
54 These functions handle special cases and exceptions in the spirit of
57 IEEE 754. In particular,
58 o cospi(NaN) is NaN,
60 o cospi(±Inf) is NaN, and an invalid operation exception is
62 raised.
63 An application wanting to check for exceptions should call feclearex‐
66 cept(FE_ALL_EXCEPT) before calling these functions. On return, if
67 fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
68 non-zero, an exception has been raised. The application can then exam‐
69 ine the result or argument vectors for exceptional values. Some vector
70 functions can raise the inexact exception even if all elements of the
71 argument array are such that the numerical results are exact.
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74 See attributes(5) for descriptions of the following attributes:
75 ┌─────────────────────────────┬─────────────────────────────┐
80 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
81 ├─────────────────────────────┼─────────────────────────────┤
82 │Interface Stability │Committed │
83 ├─────────────────────────────┼─────────────────────────────┤
84 │MT-Level │MT-Safe │
85 └─────────────────────────────┴─────────────────────────────┘
86
88 feclearexcept(3M), fetestexcept(3M), attributes(5)
89SunOS 5.11 14 Dec 2007 vcospi_(3MVEC)