Intel® Math Kernel Library 2018 Developer Reference - C
Computes inverse cosine of vector elements.
vsAcos( n, a, y );
vmsAcos( n, a, y, mode );
vdAcos( n, a, y );
vmdAcos( n, a, y, mode );
vcAcos( n, a, y );
vmcAcos( n, a, y, mode );
vzAcos( n, a, y );
vmzAcos( n, a, y, mode );
Name |
Type |
Description |
---|---|---|
n |
const int |
Specifies the number of elements to be calculated. |
a |
const float* for vsAcos, vmsAcos const double* for vdAcos, vmdAcos const MKL_Complex8* for vcAcos, vmcAcos const MKL_Complex16* for vzAcos, vmzAcos |
Pointer to an array that contains the input vector a. |
mode |
const MKL_INT64 |
Overrides global VM mode setting for this function call. See vmlSetMode for possible values and their description. |
Name |
Type |
Description |
---|---|---|
y |
float* for vsAcos, vmsAcos double* for vdAcos, vmdAcos MKL_Complex8* for vcAcos, vmcAcos MKL_Complex16* for vzAcos, vmzAcos |
Pointer to an array that contains the output vector y. |
The v?Acos function computes inverse cosine of vector elements.
Argument | Result | VM Error Status | Exception |
---|---|---|---|
+0 | +π/2 | ||
-0 | +π/2 | ||
+1 | +0 | ||
-1 | +π | ||
|X| > 1 | QNAN | VML_STATUS_ERRDOM | INVALID |
+∞ | QNAN | VML_STATUS_ERRDOM | INVALID |
-∞ | QNAN | VML_STATUS_ERRDOM | INVALID |
QNAN | QNAN | ||
SNAN | QNAN | INVALID |
See Special Value Notations for the conventions used in the table below.
RE(z) i·IM(z) |
-∞
|
-X
|
-0
|
+0
|
+X
|
+∞
|
NAN
|
---|---|---|---|---|---|---|---|
+i·∞ | +3·π/4-i·∞ | +π/2-i·∞ | +π/2-i·∞ | +π/2-i·∞ | +π/2-i·∞ | +π/4-i·∞ | QNAN-i·∞ |
+i·Y | +π-i·∞ | +0-i·∞ | QNAN+i·QNAN | ||||
+i·0 | +π-i·∞ | +π/2-i·0 | +π/2-i·0 | +0-i·∞ | QNAN+i·QNAN | ||
-i·0 | +π+i·∞ | +π/2+i·0 | +π/2+i·0 | +0+i·∞ | QNAN+i·QNAN | ||
-i·Y | +π+i·∞ | +0+i·∞ | QNAN+i·QNAN | ||||
-i·∞ | +3π/4+i·∞ | +π/2+i·∞ | +π/2+i·∞ | +π/2+i·∞ | +π/2+i·∞ | +π/4+i·∞ | QNAN+i·∞ |
+i·NAN | QNAN+i·∞ | QNAN+i·QNAN | +π/2+i·QNAN | +π/2+i·QNAN | QNAN+i·QNAN | QNAN+i·∞ | QNAN+i·QNAN |
Notes:
raises INVALID exception when real or imaginary part of the argument is SNAN
Acos(CONJ(z))=CONJ(Acos(z)).