Intel® Math Kernel Library 2019 Developer Reference - Fortran
Computes the four-quadrant inverse tangent of the ratios of the corresponding elementss of two vectors divided by π.
call vsatan2pi (n, a, b, y)
call vmsatan2pi (n, a, b, y, mode)
call vdatan2pi (n, a, b, y)
call vmdatan2pi (n, a, b, y, mode)
Name |
Type |
Description |
|---|---|---|
n |
INTEGER |
Specifies the number of elements to be calculated. |
a, b |
REAL for vsatan2pi REAL for vmsatan2pi DOUBLE PRECISION for vdatan2pi DOUBLE PRECISION for vmdatan2pi |
Pointers to the arrays containing the input vectors a and b. |
mode |
INTEGER (KIND=8) |
Overrides the global VM mode setting for this function call. See vmlSetMode for possible values and their description. |
Name |
Type |
Description |
|---|---|---|
y |
REAL for vsatan2pi REAL for vmsatan2pi DOUBLE PRECISION for vdatan2pi DOUBLE PRECISION for vmdatan2pi |
Pointer to an array containing the output vector y. |
The v?Atan2pi function computes the four-quadrant inverse tangent of the ratios of the corresponding elements of two vectors divided by π.
For the elements of the output vector y, the function computers the four-quadrant arctangent of ai/bi, with the result divided by π.
| Argument 1 | Argument 2 | Result | Exception |
|---|---|---|---|
| -∞ | -∞ | -3/4 | |
| -∞ | x < +0 | -1/2 | |
| -∞ | -0 | +1/2 | |
| -∞ | +0 | -1/2 | |
| -∞ | x > +0 | -1/2 | |
| -∞ | +∞ | -1/4 | |
| x < +0 | -∞ | -1 | |
| x < +0 | -0 | -1/2 | |
| x < +0 | +0 | -1/2 | |
| x < +0 | +∞ | -0 | |
| -0 | -∞ | -1 | |
| -0 | x < +0 | -1 | |
| -0 | -0 | -1 | |
| -0 | +0 | -0 | |
| -0 | x > +0 | -0 | |
| -0 | +∞ | -0 | |
| +0 | -∞ | +1 | |
| +0 | x < +0 | +1 | |
| +0 | -0 | +1 | |
| +0 | +0 | +0 | |
| +0 | x > +0 | +0 | |
| +0 | +∞ | +0 | |
| x > +0 | -∞ | +1 | |
| x > +0 | -0 | +1/2 | |
| x > +0 | +0 | +1/2 | |
| x > +0 | +∞ | +1/4 | |
| +∞ | -∞ | +3/4 | |
| +∞ | x < +0 | +1/2 | |
| +∞ | -0 | +1/2 | |
| +∞ | +0 | +1/2 | |
| +∞ | x > +0 | +1/2 | |
| +∞ | +∞ | +1/4 | |
| x > +0 | QNAN | QNAN | |
| x > +0 | SNAN | QNAN | INVALID |
| QNAN | x > +0 | QNAN | |
| SNAN | x > +0 | QNAN | INVALID |
| QNAN | QNAN | QNAN | |
| QNAN | SNAN | QNAN | INVALID |
| SNAN | QNAN | QNAN | INVALID |
| SNAN | SNAN | QNAN | INVALID |