v?InvSqrt

Computes an inverse square root of vector elements.

Syntax

call vsinvsqrt( n, a, y )

call vmsinvsqrt( n, a, y, mode )

call vdinvsqrt( n, a, y )

call vmdinvsqrt( n, a, y, mode )

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.
mode	INTEGER(KIND=8), INTENT(IN)	Overrides global VM mode setting for this function call. See vmlSetMode for possible values and their description.

Name

Type

Description

INTEGER, INTENT(IN)

Specifies the number of elements to be calculated.

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.

mode

INTEGER(KIND=8), INTENT(IN)

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

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.

Name

Type

Description

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.

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