v?Fmod

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

v?Fmod

The v?Fmod function performs element by element computation of the modulus function of vector a with respect to vector b .

Syntax

call vsfmod ( n , a , b , y )

call vsfmodi(n, a, inca, b, incb, y, incy)

call vmsfmod ( n , a , b , y , mode )

call vmsfmodi(n, a, inca, b, incb, y, incy, mode)

call vdfmod ( n , a , b , y )

call vdfmodi(n, a, inca, b, incb, y, incy)

call vmdfmod ( n , a , b , y , mode )

call vmdfmodi(n, a, inca, b, incb, y, incy, mode)

Include Files

mkl_vml.f90

Input Parameters

Name	Type	Description
`n`	INTEGER	Specifies the number of elements to be calculated.
`a, b`	REAL for `vsFmod` REAL for `vmsFmod` DOUBLE PRECISION for `vdFmod` DOUBLE PRECISION for `vmdFmod`	Pointers to arrays containing the input vectors `a` and `b` .
`inca` , `incb` , `incy`	INTEGER, INTENT(IN)	Specifies increments for the elements of `a` , `b` , and `y` .
`mode`	INTEGER (KIND=8)	Overrides the global VM `mode` setting for this function call. See vmlSetMode (Sets a new mode for VM functions according to the mode parameter and stores the previous VM mode to oldmode.) for possible values and their description.

Output Parameters

Name	Type	Description
`y`	REAL for `vsFmod` REAL for `vmsFmod` DOUBLE PRECISION for `vdFmod` DOUBLE PRECISION for `vmdFmod`	Pointer to an array containing the output vector `y` .

Description

The v?Fmod function computes the modulus function of each element of vector a , with respect to the corresponding elements of vector b :

\(a_{i} - b_{i}*trunc(a_{i}/b_{i})\)

In general, the modulus function fmod (a_{i}, b_{i}) returns the value a_{i} - n*b_{i} for some integer n such that if b_i is nonzero, the result has the same sign as a_i and a magnitude less than the magnitude of b_i .

Special values for Real Function v?Fmod(x, y)

Argument 1	Argument 2	Result	VM Error Status	Exception
`x` not NAN	± 0	NAN	VML_STATUS_SING	INVALID
±∞	`y` not NAN	NAN	VML_STATUS_SING	INVALID
± 0	`y` ≠ 0, not NAN	± 0
`x` finite	±∞	`x`		UNDERFLOW if `x` is subnormal
NAN	`y`	NAN
`x`	NAN	NAN

NOTE:

If element i in the result of v?Fmod is 0, its sign is that of a_i .

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

v?Fmod

Syntax

Include Files

Input Parameters

Output Parameters

Description