Naming Conventions for BLAS Routines

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

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Naming Conventions for BLAS Routines

BLAS routine names have the following structure:

<character> <name> <mod>

The <character> field indicates the data type:

s: real, single precision
c: complex, single precision
d: real, double precision
z: complex, double precision

Some routines and functions can have combined character codes, such as sc or dz .

For example, the function scasum uses a complex input array and returns a real value.

The <name> field, in BLAS level 1, indicates the operation type. For example, the BLAS level 1 routines ?dot , ?rot , ?swap compute a vector dot product, vector rotation, and vector swap, respectively.

In BLAS level 2 and 3, <name> reflects the matrix argument type:

ge: general matrix
gb: general band matrix
sy: symmetric matrix
sp: symmetric matrix (packed storage)
sb: symmetric band matrix
he: Hermitian matrix
hp: Hermitian matrix (packed storage)
hb: Hermitian band matrix
tr: triangular matrix
tp: triangular matrix (packed storage)
tb: triangular band matrix.

The <mod> field, if present, provides additional details of the operation. BLAS level 1 names can have the following characters in the <mod> field:

c: conjugated vector
u: unconjugated vector
g: Givens rotation construction
m: modified Givens rotation
mg: modified Givens rotation construction

BLAS level 2 names can have the following characters in the <mod> field:

mv: matrix-vector product
sv: solving a system of linear equations with a single unknown vector
r: rank-1 update of a matrix
r2: rank-2 update of a matrix.

BLAS level 3 names can have the following characters in the <mod> field:

mm: matrix-matrix product
sm: solving a system of linear equations with multiple unknown vectors
rk: rank-k update of a matrix
r2k: rank-2k update of a matrix.

The examples below illustrate how to interpret BLAS routine names:

ddot: <d> <dot> : real and double precision, vector-vector dot product
cdotc: <c> <dot> <c> : complex and single precision, vector-vector dot product, conjugated
cdotu: <c> <dot> <u> : complex and single precision, vector-vector dot product, unconjugated
scasum: <sc> <asum> : real and single-precision output, complex and single-precision input, sum of magnitudes of vector elements
sgemv: <s> <ge> <mv> : real and single precision, general matrix, matrix-vector product
ztrmm: <z> <tr> <mm> : complex and double precision, triangular matrix, matrix-matrix product

Sparse BLAS level 1 naming conventions are similar to those of BLAS level 1. For more information, see Naming Conventions .

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

Naming Conventions for BLAS Routines