v?Fmod

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 10/15/2026

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