Developer Reference for Intel® oneAPI Math Kernel Library for C
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v?Atan
Computes inverse tangent of vector elements.
Syntax
vsAtan( n, a, y );
vsAtanI(n, a, inca, y, incy);
vmsAtan( n, a, y, mode );
vmsAtanI(n, a, inca, y, incy, mode);
vdAtan( n, a, y );
vdAtanI(n, a, inca, y, incy);
vmdAtan( n, a, y, mode );
vmdAtanI(n, a, inca, y, incy, mode);
vcAtan( n, a, y );
vcAtanI(n, a, inca, y, incy);
vmcAtan( n, a, y, mode );
vmcAtanI(n, a, inca, y, incy, mode);
vzAtan( n, a, y );
vzAtanI(n, a, inca, y, incy);
vmzAtan( n, a, y, mode );
vmzAtanI(n, a, inca, y, incy, mode);
Include Files
- mkl.h
 
Input Parameters
Name  |  
      Type  |  
      Description  |  
     
|---|---|---|
n  |  
      const MKL_INT  |  
      Specifies the number of elements to be calculated.  |  
     
a  |  
      const float* for vsAtan, vmsAtan const double* for vdAtan, vmdAtan const MKL_Complex8* for vcAtan, vmcAtan const MKL_Complex16* for vzAtan, vmzAtan  |  
      Pointer to an array that contains the input vector a.  |  
     
inca, incy  |  
      const MKL_INT  |  
      Specifies increments for the elements of a and y.  |  
     
mode  |  
      const MKL_INT64  |  
      Overrides global VM mode setting for this function call. See vmlSetMode for possible values and their description.  |  
     
Output Parameters
Name  |  
      Type  |  
      Description  |  
     
|---|---|---|
y  |  
      float* for vsAtan, vmsAtan double* for vdAtan, vmdAtan MKL_Complex8* for vcAtan, vmcAtan MKL_Complex16* for vzAtan, vmzAtan  |  
      Pointer to an array that contains the output vector y.  |  
     
Description
The v?Atan function computes inverse tangent of vector elements.
| Argument | Result | VM Error Status | Exception | 
|---|---|---|---|
| +0 | +0 | ||
| -0 | -0 | ||
| +∞ | +π/2 | ||
| -∞ | -π/2 | ||
| QNAN | QNAN | ||
| SNAN | QNAN | INVALID | 
Specifications for special values of the complex functions are defined according to the following formula
Atan(z) = -i*Atanh(i*z).