vecLib Reference
Overview
The vecLib framework contains nine C header files (not counting vecLib.h which merely includes the others). Two of them, vDSP.h
and vDSP_translate.h
, are covered in vDSP Programming Guide and vDSP Reference.
Three of the header files are Apple’s versions of wellknown libraries which are described in detail in external references:

cblas.h
andvblas.h
are the interfaces to Apple’s implementations of BLAS. You can find reference documentation in BLAS Reference. Additional documentation on the BLAS standard, including reference implementations, can be found on the web starting from the BLAS FAQ page at these URLs: http://www.netlib.org/blas/faq.html and http://www.netlib.org/blas/blastforum/blastforum.html. 
clapack.h is the interface to Apple’s implementation of LAPACK. Documentation of the LAPACK interfaces, including reference implementations, can be found on the web starting from the LAPACK FAQ page at this URL: http://netlib.org/lapack/faq.html
This document describes the functions declared in the remaining header files: vecLibTypes.h
, vfp.h
, vForce.h
, vBasicOps.h
, vectorOps.h
, and vBigNum.h
. These files support the vector mathematical functions library (also called “vMathLib”), which runs on vector processing hardware (Altivec or SSE3) if available.
This library abstracts the vector processing capability so that code written for it will execute appropriate instructions for the processor available at runtime. For this reason, unless you are writing specialized code that targets a single CPU, you should generally use these functions rather than directly using vector instructions. By using these functions, your code does not have to deal with subtle differences in vector instruction availability between different microarchitectures, freeing you to focus on the problem you are trying to solve. Also, code written using vecLib tends to be easier to port to different CPU architectures (porting your core libraries to ARM on iOS, for example).
vecLibTypes.h
The vecLibTypes.h header file defines a set of vector data types (vFloat
, vUInt32
, etc.), which represent 128bit vectors containing values of type float
, UInt32
, etc. The vBasicOps.h and vfp.h headers make use of these types.
The type names all begin with the letter “v,” followed by a mnemonic for the scalar data type used for elements of the vector. For example, vUInt32
, vSInt16
, vFloat
, etc.
vBasicOps.h
vBasicOps.h declares a set of basic arithmetic and logical functions on 128bit vectors, using the integer types from vecLibTypes.h.
The function names begin with “v,” followed by a mnemonic for the type of operation, e.g. “S” or “U” for signed or unsigned, then the width of the operation, then the name of the operation. For example, vS8Divide
performs division of signed 8bit values packed into 128bit vectors.
vfp.h
vfp.h declares a set of floatingpoint arithmetic, transcendental and trigonometric functions, on 128bit vectors, using the floatingpoint types from vecLibTypes.h.
These functions are named with their customary mathematical names, prefixed with the letter “v”, and all except vtablelookup()
have the suffix “f” to indicate that they work with singleprecision floatingpoint data. For example, vcosf
is the singleprecision cosine function.
vForce.h
vForce.h declares a set of trigonometric and transcendental functions in terms of C arrays (double *
or float *
), which can be of any desired length. Internally, the C arrays are converted piecewise into collections of 128bit vectors, if appropriate for the current architecture.
The functions declared in vForce.h are named with the customary mathematical names, but with the prefix “vv.” Each mathematical function is available in two variants: one for singleprecision floatingpoint data and one for doubleprecision data. The singleprecision forms have the suffix “f”, while the doubleprecision forms have no suffix. For example, vvcosf
is the singleprecision cosine function, while vvcos
is the doubleprecision variant.
All of the vForce.h functions follow a common format:

The return type is
void
. 
The first parameter points to an array to hold the results. (The only exceptions are
vvsincosf()
andvvsincos()
, which have two result arrays pointed to by the first two parameters.) 
One or more parameters point to operand arrays, the same length as the result array.

The last parameter is the array length.
vectorOps.h
vectorOps.h declares a set of vector and matrix BLAS functions on arrays of 128bit vectors containing singleprecision floatingpoint values. The arrays can be of any desired length, but the number of float
elements must be a multiple of 4.
vBigNum.h
vBigNum.h provides arithmetic and logical operations on large integers, which may be 128, 256, 512, or 1024 bits in length. It defines types for these values, and internally processes them as collections of 128bit vectors.
vBigNum.h defines its own set of data types to represent large integer quantities, such as vS128
for a signed, 128bit integer or vU1024
for an unsigned, 1024bit integer. The function names begin with the data type name, followed by the name of the operation. For example, vS512Add
performs addition of two 128bit signed integers.
The functions perform logical and arithmetic operations on scalar values that may be 128, 256, 512, or 1024 bits in width. These values are implemented as structures of one, two, four, or eight 128bit vectors, and the operations execute on the available vectorprocessing hardware if possible.
The functions have names that are compatible with those in vBasicOps.h.
Threading Model
In versions of vecLib prior to OS X v10.7, many vecLib routines used multiple POSIX threads to improve performance. In some cases, this could cause performance problems in applications that use large numbers of POSIX threads.
An application can limit the number of threads used by vecLib by setting the environment variable VECLIB_MAXIMUM_THREADS
as follows:
#include <stdlib.h> 
setenv("VECLIB_MAXIMUM_THREADS", "1", true); 
To remove the limit, you can unset the environment variable as follows:
unsetenv("VECLIB_MAXIMUM_THREADS"); 
In OS X v10.7, these routines use Grand Central Dispatch, so the use of this environment variable should no longer be necessary.
For More Information
For information about membership in Apple’s developer program, go to this URL:
http://developer.apple.com/membership/
For information about the Velocity Engine, go to this URL:
http://developer.apple.com/hardwaredrivers/ve/index.html
For general technical support from Apple, go to this URL:
Functions by Task
FloatingPoint Arithmetic and Auxiliary Functions (from vfp.h)
Exponential and Logarithmic Functions (from vfp.h)
Trigonometric Functions (from vfp.h)
Hyperbolic Functions (from vfp.h)
Power Functions (from vfp.h)
Remainder Functions (from vfp.h)
Inquiry Functions (from vfp.h)
ArrayOriented Arithmetic and Auxiliary Functions (from vForce.h)

vvceil

vvceilf

vvcopysign

vvcopysignf

vvdiv

vvdivf

vvfabs

vvfabsf

vvfloor

vvfloorf

vvfmod

vvfmodf

vvint

vvintf

vvnextafter

vvnextafterf

vvnint

vvnintf

vvrsqrt

vvrsqrtf

vvsqrt

vvsqrtf

vvrec

vvrecf

vvremainder

vvremainderf
ArrayOriented Exponential and Logarithmic Functions (from vForce.h)

vvexp

vvexpf

vvexp2

vvexp2f

vvexpm1

vvexpm1f

vvlog

vvlogf

vvlog1p

vvlog1pf

vvlog2

vvlog2f

vvlog10

vvlog10f

vvlogb

vvlogbf
ArrayOriented Power Functions (from vForce.h)
ArrayOriented Trigonometric Functions (from vForce.h)

vvsin

vvsinf

vvsinpi

vvsinpif

vvcos

vvcosf

vvcospi

vvcospif

vvcosisin

vvcosisinf

vvsincos

vvsincosf

vvtan

vvtanf

vvtanpi

vvtanpif

vvasin

vvasinf

vvacos

vvacosf

vvatan

vvatanf

vvatan2

vvatan2f
ArrayOriented Hyperbolic Functions (from vForce.h)
Functions
vacosf
For each vector element, calculates the arccosine. Results are in the interval [0, pi].
vFloat vacosf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vacoshf
For each vector element, calculates the inverse hyperbolic cosine of X
.
vFloat vacoshf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vasinf
For each vector element, calculates the arcsine. Results are in the interval [pi/2, pi/2].
vFloat vasinf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vasinhf
For each vector element, calculates the inverse hyperbolic sine of X
.
vFloat vasinhf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vatan2f
For each vector element, calculates the arctangent of arg2
/arg1
in the interval [pi,pi] using the sign of both arguments to determine the quadrant of the computed value.
vFloat vatan2f ( vFloat arg1, vFloat arg2 );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vatanf
For each vector element, calculates the arctangent. Results are in the interval [pi/2, pi/2].
vFloat vatanf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vatanhf
For each vector element, calculates the inverse hyperbolic tangent of X
.
vFloat vatanhf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vceilf
Computes the ceiling of values in a vector of floatingpoint values.
vFloat vceilf ( vFloat A );
Parameters
 A

The input vector.
Return Value
Returns a vector of floatingpoint values, each of which is the ceiling of the corresponding value in A
.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vclassifyf
For each vector element, returns the class of the argument (one of the FP_ ... constants defined in math.h).
vUInt32 vclassifyf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vcopysignf
For each vector element, produces a value with the magnitude of arg2
and sign arg1
. Note that the order of the arguments matches the recommendation of the IEEE 754 floatingpoint standard, which is opposite from the SANE copysign function.
vFloat vcopysignf ( vFloat arg2, vFloat arg1 );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vcosf
For each vector element, calculates the cosine.
vFloat vcosf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vcoshf
For each vector element, calculates the hyperbolic cosine of X
.
vFloat vcoshf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vdivf
For each vector element, calculates A
/B
.
vFloat vdivf ( vFloat A, vFloat B );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vexpf
For each vector element, calculates the exponential of X.
vFloat vexpf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vexpm1f
For each vector element, calculates ExpM1(x) = Exp(x)  1. But, for small enough arguments, ExpM1(x) is expected to be more accurate than Exp(x)  1.
vFloat vexpm1f ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vfloorf
Computes the floor of values in a vector of floatingpoint values.
vFloat vfloorf ( vFloat A );
Parameters
 A

The input vector.
Return Value
Returns a vector of floatingpoint values, each of which is the floor of the corresponding value in A
.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vfmodf
For each vector element, calculates X
modulo Y
.
vFloat vfmodf ( vFloat X, vFloat Y );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vipowf
For each vector element, calculates X
to the integer power of Y
.
vFloat vipowf ( vFloat X, vSInt32 Y );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vlog10f
Computes the base10 logarithm of values in a vector.
vFloat vlog10f ( vFloat X );
Parameters
 X

The source vector.
Return Value
Returns a vector of floating point values, each of which is the base10 logarithm of the corresponding value in the source vector.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vlog1pf
For each vector element, calculates Log1P = Log(1 + x). But, for small enough arguments, Log1P is expected to be more accurate than Log(1 + x).
vFloat vlog1pf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vlogbf
For each vector element, extracts the exponent of X
, as a signed integral value. A subnormal argument is treated as though it were first normalized. Thus: 1 <= x * 2^(logb(x)) < 2.
vFloat vlogbf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vlogf
For each vector element, calculates the natural logarithm of X
.
vFloat vlogf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vnextafterf
For each vector element, calculates the next representable value after x
in the direction of y
. If x
is equal to y
, then y
is returned.
vFloat vnextafterf ( vFloat x, vFloat y );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vnintf
Rounds to the nearest integer (nearest even for ties).
vFloat vnintf ( vFloat A );
Parameters
 A

The input vector.
Return Value
Returns a vector of floatingpoint values, each of which is the result of rounding the corresponding value in A
to the nearest integer, with ties rounded to the nearest even integer.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vpowf
For each vector element, calculates X
to the floatingpoint power of Y
. The result is more accurate than using exp(log(X
)*Y
).
vFloat vpowf ( vFloat X, vFloat Y );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vrecf
Computes the reciprocal of values in a vector.
vFloat vrecf ( vFloat A );
Parameters
 A

The source vector
Return Value
Returns a vector containing the reciprocals of the values in the source vector.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vremainderf
For each vector element, calculates the remainder of X
/Y
, according to the IEEE 754 floatingpoint standard.
vFloat vremainderf ( vFloat X, vFloat Y );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vremquof
For each vector element, calculates the remainder of X
/Y
, according to the SANE standard. It stores into QUO
the 7 loworder bits of the integer quotient, such that 127 <= QUO
<= 127.
vFloat vremquof ( vFloat X, vFloat Y, vUInt32 *QUO );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vrsqrtf
For each vector element, calculates the inverse of the square root of X
.
vFloat vrsqrtf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vscalbf
For each vector element, calculates x * 2^n efficiently. This is not normally done by computing 2^n explicitly.
vFloat vscalbf ( vFloat X, vSInt32 n );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vsignbitf
For each vector element, returns a nonzero value if and only if the sign of arg
is negative. This includes NaNs, infinities and zeros.
vUInt32 vsignbitf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vsincosf
Simultaneously computes sine and cosine of values in a vector.
vFloat vsincosf ( vFloat arg, vFloat *sine_result );
Parameters
 arg

The source vector.
 sine_result

An output vector. On return, this contains the result of
sin(x)
for each value (x
) in the source vector.
Return Value
Returns a vector that contains the result of cos(x)
for each value (x
) in the source vector.
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vsinf
For each vector element, calculates the sine.
vFloat vsinf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vsinhf
For each vector element, calculates the hyperbolic sine of X
.
vFloat vsinhf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vsqrtf
For each vector element, calculates the square root of X
.
vFloat vsqrtf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vtablelookup
For each vector element of Index_Vect
, returns the corresponding value from Table
.
vUInt32 vtablelookup ( vSInt32 Index_Vect, uint32_t *Table );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vtanf
For each vector element, calculates the tangent.
vFloat vtanf ( vFloat arg );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vtanhf
For each vector element, calculates the hyperbolic tangent of X
.
vFloat vtanhf ( vFloat X );
Availability
 Available in iOS 6.0 and later.
Declared In
vfp.h
vvacos
For each doubleprecision array element, sets y
to the arccosine of x
.
void vvacos ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvacosf
For each singleprecision array element, sets y
to the arccosine of x
.
void vvacosf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvacosh
For each doubleprecision array element, sets y
to the inverse hyperbolic cosine of x
.
void vvacosh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvacoshf
For each singleprecision array element, sets y
to the inverse hyperbolic cosine of x
.
void vvacoshf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvasin
For each doubleprecision array element, sets y
to the arcsine of x
.
void vvasin ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvasinf
For each singleprecision array element, sets y
to the arcsine of x
.
void vvasinf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvasinh
For each doubleprecision array element, sets y
to the inverse hyperbolic sine of x
.
void vvasinh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvasinhf
For each singleprecision array element, sets y
to the inverse hyperbolic sine of x
.
void vvasinhf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatan
For each doubleprecision array element, sets y
to the arctangent of x
.
void vvatan ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatan2
For each doubleprecision array element, sets z
to the arctangent of y
/x
.
void vvatan2 ( double *, const double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatan2f
For each singleprecision array element, sets z
to the arctangent of y
/x
.
void vvatan2f ( float *, const float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatanf
For each singleprecision array element, sets y
to the arctangent of x
.
void vvatanf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatanh
For each doubleprecision array element, sets y
to the inverse hyperbolic tangent of x
.
void vvatanh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvatanhf
For each singleprecision array element, sets y
to the inverse hyperbolic tangent of x
.
void vvatanhf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvceil
For each doubleprecision array element, sets y
to the ceiling of x
.
void vvceil ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvceilf
For each singleprecision array element, sets y
to the ceiling of x
.
void vvceilf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcopysign
Copies an array, setting the sign of each value based on a second array.
void vvcopysign ( double *, double *, const double *, const int * );
Parameters
 z

The output array.
 y

The magnitude input array.
 x

The sign input array.
 n

The address of an integer containing the number of elements to copy.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcopysignf
Copies an array, setting the sign of each value based on a second array.
void vvcopysignf ( float *, const float *, const float *, const int * );
Parameters
 result

Storage for the result. Modified on return.
 signs

Array containing values with the desired signs.
 float

Array containing values with the desired values.
 int

The length of the arrays.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcos
For each doubleprecision array element, sets y
to the cosine of x
.
void vvcos ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcosf
For each singleprecision array element, sets y
to the cosine of x
.
void vvcosf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcosh
For each doubleprecision array element, sets y
to the hyperbolic cosine of x
.
void vvcosh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcoshf
For each singleprecision array element, sets y
to the hyperbolic cosine of x
.
void vvcoshf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcosisin
For each doubleprecision array element, sets the real part of C
to the sine of x
and the imaginary part of C
to the cosine of x
.
void vvcosisin ( __double_complex_t *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcosisinf
For each singleprecision array element, sets the real part of C
to the cosine of x
and the imaginary part of C
to the sine of x
.
void vvcosisinf ( __float_complex_t *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcospi
Sets each element y[i]
to the sin(pi * x[i])
for i
in 0..n1
.
void vvcospi ( double *, const double *, const int * );
Parameters
 y

An input array of doubleprecision floating point numbers
 x

An output array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvcospif
Sets each element y[i]
to the sin(pi * x[i])
for i
in 0..n1
.
void vvcospif ( float *, const float *, const int * );
Parameters
 y

An input array of singleprecision floating point values.
 x

An output array of singleprecision floating point values.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvdiv
For each doubleprecision array element, sets z
to y
/x
.
void vvdiv ( double *, const double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvdivf
For each singleprecision array element, sets z
to y
/x
.
void vvdivf ( float *, const float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexp
For each doubleprecision array element, sets y
to the exponential of x
.
void vvexp ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexp2
Sets each element y[i]
to 2
raised to (x[i])
for i
in 0..n1
.
void vvexp2 ( double *, const double *, const int * );
Parameters
 y

An input array of doubleprecision floating point numbers
 x

An output array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexp2f
Sets each element y[i]
to 2
raised to (x[i])
for i
in 0..n1
.
void vvexp2f ( float *, const float *, const int * );
Parameters
 y

An input array of singleprecision floating point values.
 x

An output array of singleprecision floating point values.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexpf
For each singleprecision array element, sets y
to the exponential of x
.
void vvexpf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexpm1
Returns (e^x)1
for each element y[i]
.
void vvexpm1 ( double *, const double *, const int * );
Parameters
 y

An input array of doubleprecision floating point numbers
 x

An output array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Discussion
This is accurate for very small values of x[i]
.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvexpm1f
Computes (e^x)1
for each element in an array.
void vvexpm1f ( float *, const float *, const int * );
Parameters
 result

An array, modified on return, where the results are stored.
 src

The input array.
 count

The number of values in the input and result arrays.
Discussion
Provides additional accuracy for values of x
near 1
.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfabs
Sets each element y[i]
to abs(x[i]1)
for i
in 0..n1
.
void vvfabs ( double *, const double *, const int * );
Parameters
 y

An input array of doubleprecision floating point numbers
 x

An output array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfabsf
Sets each element y[i]
to abs(x[i]1)
for i
in 0..n1
.
void vvfabsf ( float *, const float *, const int * );
Parameters
 y

An input array of singleprecision floating point values.
 x

An output array of singleprecision floating point values.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfloor
For each doubleprecision array element, sets y
to the floor of x
.
void vvfloor ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfloorf
For each singleprecision array element, sets y
to the floor of x
.
void vvfloorf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfmod
Sets each element y[i]
to the floating point remainder of (y[i]/x[i])
for i
in 0..n1
.
void vvfmod ( double *, double *, const double *, const int * );
Parameters
 z

An output array of doubleprecision floating point numbers.
 y

Numerator input array of doubleprecision floating point numbers.
 x

Denominator input array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvfmodf
Computes the remainders after dividing values in a pair of arrays.
void vvfmodf ( float *, const float *, const float *, const int * );
Parameters
 result

An array, modified on return, where the results are stored.
 divisors

An array of divisors.
 dividends

An array of dividends.
 count

The number of values in the input and result arrays.
Discussion
On return, the result
array contains the remainders after calculating dividend[i] / divisor[i]
for each value of i
from 0
through count1
.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvint
For each doubleprecision array element, sets y
to the integer truncation of x
.
void vvint ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvintf
For each singleprecision array element, sets y
to the integer truncation of x
.
void vvintf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog
For each doubleprecision array element, sets y
to the natural logarithm of x
.
void vvlog ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog10
For each doubleprecision array element, sets y
to the base 10 logarithm of x
.
void vvlog10 ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog10f
For each singleprecision array element, sets y
to the base 10 logarithm of x
.
void vvlog10f ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog1p
Sets each element y[i]
to log(1+x[i])
for i
in 0..n1
.
void vvlog1p ( double *, const double *, const int * );
Parameters
 y

An output array of doubleprecision floating point numbers.
 x

An input array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog1pf
Computes the natural logarithm of a value plus 1.
void vvlog1pf ( float *, const float *, const int * );
Parameters
 results

An array where results are stored on return.
 values

The source array.
 count

A pointer to an integer containing the number of elements to process.
Discussion
This algorithm computes
log(1+x)
for each element x
in the source array.
This algorithm is tuned to provide increased accuracy for values of x
near 1
.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog2
Sets each element y[i]
to the base2 logarithm of x[i]
for i
in 0..n1
.
void vvlog2 ( double *, const double *, const int * );
Parameters
 y

An output array of doubleprecision floating point numbers.
 x

An input array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlog2f
Sets each element y[i]
to the base 2 logarithm of x[i]
for i
in 0..n1
.
void vvlog2f ( float *, const float *, const int * );
Parameters
 y

An output array of singleprecision floating point numbers.
 x

An input array of singleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlogb
Sets each element y[i]
to the exponent of x[i]
for i
in 0..n1
.
void vvlogb ( double *, const double *, const int * );
Parameters
 y

An output array of doubleprecision floating point numbers.
 x

An input array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Discussion
Floating point numbers are internally represented as a mantissa multiplied times a base raised to an exponent. That exponent is returned in the output array.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlogbf
Sets each element y[i]
to the exponent of x[i]
for i
in 0..n1
.
void vvlogbf ( float *, const float *, const int * );
Parameters
 y

An array where results are stored on return.
 x

The source array.
 n

A pointer to an integer containing the number of elements to process.
Discussion
Floating point numbers are internally represented as a mantissa multiplied times a base raised to an exponent. That exponent is returned in the output array.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvlogf
For each singleprecision array element, sets y
to the natural logarithm of x
.
void vvlogf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvnextafter
Sets each element z[i]
to the next machinerepresentable value from y[i]
towards x[i]
for i
in 0..n1
.
void vvnextafter ( double *, double *, const double *, const int * );
Parameters
 z

An output array of doubleprecision floating point numbers.
 y

An input array of doubleprecision floating point numbers.
 x

An input array of doubleprecision floating point numbers.
 n

A pointer to an integer containing the number of floating point elements to set.
Discussion
Not all values can be represented as a floatingpoint value of a given precision. This function sets a value in z[i]
that is either minimally larger than the value in y[i]
(if x[i]
is larger than y[i]
) or minimally smaller than the value in y[i]
(if x[i]
is smaller than y[i]
).
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvnextafterf
Sets each element z[i]
to the next machinerepresentable value from y[i]
towards x[i]
for i
in 0..n1
.
void vvnextafterf ( float *, const float *, const float *, const int * );
Parameters
 z

An array where results are stored on return.
 y

An array of floatingpoint values providing the direction relative to
x
.  x

An array of floatingpoint values providing the starting point.
 n

A pointer to an integer containing the number of elements to process.
Discussion
Not all values can be represented as a floatingpoint value of a given precision. This function sets a value in z[i]
that is either minimally larger than the value in y[i]
(if x[i]
is larger than y[i]
) or minimally smaller than the value in y[i]
(if x[i]
is smaller than y[i]
).
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvnint
For each doubleprecision array element, sets y
to the nearest integer to x
.
void vvnint ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvnintf
For each singleprecision array element, sets y
to the nearest integer to x
.
void vvnintf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvpow
For each doubleprecision array element, sets z
to x
raised to the power of y
.
void vvpow ( double *, const double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvpowf
For each singleprecision array element, sets z
to x
raised to the power of y
.
void vvpowf ( float *, const float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvrec
For each doubleprecision array element, sets y
to the reciprocal of y
.
void vvrec ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvrecf
For each singleprecision array element, sets y
to the reciprocal of y
.
void vvrecf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvremainder
Sets z[i]
to the remainder relative to a roundtoeven division of y[i]/x[i]
for each i
in 0..n1
.
void vvremainder ( double *, double *, const double *, const int * );
Parameters
 z

An array for storing the results.
 y

An array of divisors.
 x

An array of dividends.
 n

A pointer to an integer containing the number of elements to process.
Discussion
This function performs the equivalent of vnintf
for each dividend/divisor pair, then multiplies the result by the divisor, and subtracts the result from the dividend.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvremainderf
Computes the remainder relative to a roundtoeven division.
void vvremainderf ( float *, const float *, const float *, const int * );
Parameters
 results

An array for storing the results.
 divisors

An array of divisors.
 dividends

An array of dividends.
 count

A pointer to an integer containing the number of elements to process.
Discussion
This function performs the equivalent of vnintf
for each dividend/divisor pair, then multiplies the result by the divisor, and subtracts the result from the dividend.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvrsqrt
For each doubleprecision array element, sets y
to the reciprocal of the square root of x
.
void vvrsqrt ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvrsqrtf
For each singleprecision array element, sets y
to the reciprocal of the square root of x
.
void vvrsqrtf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsin
For each doubleprecision array element, sets y
to the sine of x
.
void vvsin ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsincos
For each doubleprecision array element, sets z
to the sine of x
and y
to the cosine of x
.
void vvsincos ( double *, double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsincosf
For each singleprecision array element, sets z
to the sine of x
and y
to the cosine of x
.
void vvsincosf ( float *, float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsinf
For each singleprecision array element, sets y
to the sine of x
.
void vvsinf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsinh
For each doubleprecision array element, sets y
to the hyperbolic sine of x
.
void vvsinh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsinhf
For each singleprecision array element, sets y
to the hyperbolic sine of x
.
void vvsinhf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsinpi
Sets y[i]
to sin(pi * x[i])
for i
in 0..n1
.
void vvsinpi ( double *, const double *, const int * );
Parameters
 y

An array where results are stored on return.
 x

The source array.
 n

A pointer to an integer containing the number of elements to process.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsinpif
Sets y[i]
to sin(pi * x[i])
for i
in 0..n1
.
void vvsinpif ( float *, const float *, const int * );
Parameters
 y

An array where results are stored on return.
 x

The source array.
 n

A pointer to an integer containing the number of elements to process.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsqrt
For each doubleprecision array element, sets y
to the square root of x
.
void vvsqrt ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvsqrtf
For each singleprecision array element, sets y
to the square root of x
.
void vvsqrtf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtan
For each doubleprecision array element, sets y
to the tangent of x
.
void vvtan ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtanf
For each singleprecision array element, sets y
to the tangent of x
.
void vvtanf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtanh
For each doubleprecision array element, sets y
to the hyperbolic tangent of x
.
void vvtanh ( double *, const double *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtanhf
For each singleprecision array element, sets y
to the hyperbolic tangent of x
.
void vvtanhf ( float *, const float *, const int * );
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtanpi
Sets y[i]
to tan(pi * x[i])
for i
in 0..n1
.
void vvtanpi ( double *, const double *, const int * );
Parameters
 y

An array where results are stored on return.
 x

The source array.
 n

A pointer to an integer containing the number of elements to process.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
vvtanpif
Sets y[i]
to tan(pi * x[i])
for i
in 0..n1
.
void vvtanpif ( float *, const float *, const int * );
Parameters
 y

An array where results are stored on return.
 x

The source array.
 n

A pointer to an integer containing the number of elements to process.
Availability
 Available in iOS 5.0 and later.
Declared In
vForce.h
Data Types
All data structures passed to vecLib must be naturally aligned. For example, a 32bit floatingpoint value must be aligned to a fourbyte boundary. Many routines in vecLib generate exceptions on unaligned data.
vUInt8
A 128bit vector packed with unsigned char
values.
typedef vector unsigned char vUInt8;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vSInt8
A 128bit vector packed with signed char
values.
typedef vector signed char vSInt8;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vUInt16
A 128bit vector packed with unsigned short
values.
typedef vector unsigned short vUInt16;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vSInt16
A 128bit vector packed with signed short
values.
typedef vector signed short vSInt16;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vUInt32
A 128bit vector packed with unsigned int
values.
typedef vector unsigned int vUInt32;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vSInt32
A 128bit vector packed with signed int
values.
typedef vector signed int vSInt32;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vUInt64
A 128bit vector packed with uint64_t
values.
typedef vector unsigned int vUInt64;
Availability
 Available in iOS 7.0 and later.
Declared In
vecLibTypes.h
vSInt64
A 128bit vector packed with int64_t
values.
typedef vector signed int vSInt64;
Availability
 Available in iOS 7.0 and later.
Declared In
vecLibTypes.h
vFloat
A 128bit vector packed with float
values.
typedef vector float vFloat;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
vDouble
A 128bit vector packed with double
values.
typedef double vDouble __attribute__((__vector_size__ (16)));
vBool32
A 128bit vector packed with bool int
values.
typedef vector bool int vBool32;
Availability
 Available in iOS 4.0 and later.
Declared In
vecLibTypes.h
__float_complex_t
A singleprecision complex number type.
typedef complex float __float_complex_t;
Declared In
__double_complex_t
A doubleprecision complex number type.
typedef complex double __double_complex_t;
Declared In
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