Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

cblas_gemm_bf16bf16f32

Computes a matrix-matrix product with general bfloat16 matrices.

Syntax

void
cblas_gemm_bf16bf16f32
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_TRANSPOSE
transa
,
const
CBLAS_TRANSPOSE
transb
,
const
MKL_INT
m
,
const
MKL_INT
n
,
const
MKL_INT
k
,
const
float
alpha
,
const
MKL_BF16
*a
,
const
MKL_INT
lda
,
const
MKL_BF16
*b
,
const
MKL_INT
ldb
,
const
float
beta
,
float
*c
const
MKL_INT
ldc,
);
Include Files
  • mkl.h
Description
The
cblas_gemm_bf16bf16f32
 routines compute a scalar-matrix-matrix product and adds the result to a scalar-matrix product. The operation is defined as:
C := alpha*(op(A) *(op(B) + beta*C
where :

    op(
    X
    )
     is one of
    op(
    X
    ) =
    X
     or
    op(
    X
    ) =
    X
    T
    ,

    alpha
     and
    beta
     are scalars,

    A
    ,
    B
    , and
    C
     are matrices

    op(
    A
    )
     is
    m
    -by-
    k
     matrix,

    op(
    B
    )
     is
    k
    -by-
    n
     matrix,

    C
     is an
    m
    -by-
    n
     matrix.

Input Parameters
Layout
Specifies whether two-dimensional array storage is row-major (
CblasRowMajor
) or column-major (
CblasColMajor
).
transa
Specifies the form of op(
A
) used in the matrix multiplication:
if
transa
=
CblasNoTrans
, then
op(
A
) =
A
;
if
transa
=
CblasTrans
, then
op(
A
) =
A
T
.
transb
Specifies the form of op(
B
) used in the matrix multiplication:
if
transb
=
CblasNoTrans
, then
op(
B
) =
B
;
if
transb
=
CblasTrans
, then
op(
B
) =
B
T
.
m
Specifies the number of rows of the matrix
op(
A
)
 and of the matrix
C
. The value of
m
 must be at least zero.
n
Specifies the number of columns of the matrix
op(
B
)
 and the number of columns of the matrix
C
. The value of
n
 must be at least zero.
k
Specifies the number of columns of the matrix
op(
A
)
 and the number of rows of the matrix
op(
B
)
. The value of
k
 must be at least zero.
alpha
Specifies the scalar
alpha
.
a
transa
=
CblasNoTrans
transa
=
CblasTrans
Layout
 =
CblasColMajor
Array, size
lda
*
k
Before entry, the leading
m
-by-
k
 part of the array
a
 must contain the matrix
A
.
Array, size
lda
*
m
Before entry, the leading
k
-by-
m
 part of the array
a
 must contain the matrix
A
.
Layout
 =
CblasRowMajor
Array, size
lda
*
m
Before entry, the leading
k
-by-
m
 part of the array
a
 must contain the matrix.
Array, size
lda
*
k
Before entry, the leading
m
-by-
k
 part of the array
a
 must contain the matrix.
lda
Specifies the leading dimension of
a
 as declared in the calling (sub)program.
transa
=
CblasNoTrans
transa
=
CblasTrans
Layout
 =
CblasColMajor
lda
 must be at least
max(1,
m
)
.
lda
 must be at least
max(1,
k
)
.
Layout
 =
CblasRowMajor
lda
 must be at least
max(1,
k
)
.
lda
 must be at least
max(1,
m
)
.
b
transb
=
CblasNoTrans
transb
=
CblasTrans
Layout
 =
CblasColMajor
Array, size
ldb
 by
n
Before entry, the leading
k
-by-
n
 part of the array
b
 must contain the matrix
B
.
Array, size
ldb
 by
k
Before entry the leading
n
-by-
k
 part of the array
b
 must contain the matrix
B
.
Layout
 =
CblasRowMajor
Array, size
ldb
 by
k
Before entry the leading
n
-by-
k
 part of the array
b
 must contain the matrix
B
.
Array, size
ldb
 by
n
Before entry, the leading
k
-by-
n
 part of the array
b
 must contain the matrix
B
.
ldb
Specifies the leading dimension of
b
 as declared in the calling (sub)program.
transb
=
CblasNoTrans
transb
=
CblasTrans
Layout
 =
CblasColMajor
ldb
 must be at least
max(1,
k
)
.
ldb
 must be at least
max(1,
n
)
.
Layout
 =
CblasRowMajor
ldb
 must be at least
max(1,
n
)
.
ldb
 must be at least
max(1,
k
)
.
beta
Specifies the scalar
beta
. When
beta
 is equal to zero, then
c
 need not be set on input.
c
Layout
 =
CblasColMajor
Array, size
ldc
 by
n
. Before entry, the leading
m
-by-
n
 part of the array
c
 must contain the matrix
C
, except when
beta
 is equal to zero, in which case
c
 need not be set on entry.
Layout
 =
CblasRowMajor
Array, size
ldc
 by
m
. Before entry, the leading
n
-by-
m
 part of the array
c
 must contain the matrix
C
, except when
beta
 is equal to zero, in which case
c
 need not be set on entry.
ldc
Specifies the leading dimension of
c
 as declared in the calling (sub)program.
Layout
 =
CblasColMajor
ldc
 must be at least
max(1,
m
)
.
Layout
 =
CblasRowMajor
ldc
 must be at least
max(1,
n
)
.
Output Parameters
c
Overwritten by
alpha
* op(
A
) * op(
B
) +
beta
*
C
.

Example

For examples of routine usage, see these code examples in the
Intel® oneAPI Math Kernel Library
 installation directory:
  • cblas_gemm_bf16bf16f32
    :
    examples\cblas\source\cblas_gemm_bf16bf16f32x.c
Application Notes
On architectures without native bfloat16 hardware instructions, matrix
A
 and
B
 are upconverted to single precision and
SGEMM
 is called to compute matrix multiplication operation.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.