Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 3/22/2024
Public

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v?InvSqrt

Computes an inverse square root of vector elements.

Syntax

call vsinvsqrt( n, a, y )

call vsinvsqrti(n, a, inca, y, incy)

call vmsinvsqrt( n, a, y, mode )

call vmsinvsqrti(n, a, inca, y, incy, mode)

call vdinvsqrt( n, a, y )

call vdinvsqrti(n, a, inca, y, incy)

call vmdinvsqrt( n, a, y, mode )

call vmdinvsqrti(n, a, inca, y, incy, mode)

Include Files

  • mkl_vml.f90

Input Parameters

Name

Type

Description

n

INTEGER, INTENT(IN)

Specifies the number of elements to be calculated.

a

DOUBLE PRECISION for vdinvsqrt, vmdinvsqrt

REAL, INTENT(IN) for vsinvsqrt, vmsinvsqrt

DOUBLE PRECISION, INTENT(IN) for vdinvsqrt, vmdinvsqrt

Array that specifies the input vector a.

inca, incy

INTEGER, INTENT(IN)

Specifies increments for the elements of a and y.

mode

INTEGER(KIND=8), INTENT(IN)

Overrides global VM mode setting for this function call. See vmlSetMode for possible values and their description.

Output Parameters

Name

Type

Description

y

DOUBLE PRECISION for vdinvsqrt, vmdinvsqrt

REAL, INTENT(OUT) for vsinvsqrt, vmsinvsqrt

DOUBLE PRECISION, INTENT(OUT) for vdinvsqrt, vmdinvsqrt

Array that specifies the output vector y.

Description

The v?InvSqrt function computes an inverse square root of vector elements.

Special Values for Real Function v?InvSqrt(x)
Argument Result VM Error Status Exception
X < +0 QNAN VML_STATUS_ERRDOM INVALID
+0 + VML_STATUS_SING ZERODIVIDE
-0 - VML_STATUS_SING ZERODIVIDE
- QNAN VML_STATUS_ERRDOM INVALID
+ +0    
QNAN QNAN    
SNAN QNAN   INVALID