DocumentazioneSezioni
MQL5 RiferimentoMetodi Matriciali e VettorialiOpenBLASBLAS Level 2 

BLAS Level 2

The BLAS Level 2 section describes functions for performing operations between matrices and vectors that implement second-level linear algebra computations — matrix–vector multiplication, linear combinations, and rank updates of matrices. These functions implement the standard procedures of the BLAS (Level 2) library and provide efficient computation for real, complex, and Hermitian matrices.

BLAS Level 2 functions are designed for:

  • computing matrix–vector products;
  • updating matrices (rank-1 and rank-2 modifications);
  • working with specific matrix types — symmetric, Hermitian, and triangular;
  • performing computations with support for different data types: float, double, complexf, and complex.

All functions return true if successful and false in case of an error.

Function

Action

BlasL2GeMV

Computes a matrix-vector product using a general m-by-n matrix. y = alpha * op(A) * x + beta * y. BLAS function GEMV.

BlasL2SyMV

Computes a matrix-vector product for a symmetric n-by-n matrix. y = alpha*A*x + beta*y. BLAS function SYMV.

BlasL2HeMV

Computes a matrix-vector product for a Hermitian n-by-n matrix. y = alpha*A*x + beta*y. BLAS function HEMV.

BlasL2TrMV

Computes a matrix-vector product using a triangular n-by-n matrix. y = op(A) * x. BLAS function TRMV.

BlasL2GeR

Performs a rank-1 update of a general m-by-n matrix. AU = alpha*x*y + A. BLAS functions GER, GERU.

BlasL2GeRC

Performs a rank-1 conjugated update of a general m-by-n matrix. AU = alpha * x * conjg(y) + A. BLAS function GERC.

BlasL2SyR

Performs a rank-1 update of a symmetric n-by-n matrix. AU = alpha*x*x + A. BLAS function SYR.

BlasL2HeR

Performs a rank-1 conjugated update of a Hermitian n-by-n matrix. AU = alpha * x * conjg(x) + A. BLAS function HER2.

BlasL2SyR2

Performs a rank-2 update of a symmetric n-by-n matrix. AU = alpha*x*y + alpha*y*x + A. BLAS function SYR2.

BlasL2HeR2

Performs a rank-2 conjugated update of a Hermitian n-by-n matrix. AU = alpha * x * conjg(y) + conjg(alpha) * y * conjg(x) + A. BLAS function HER2.

Main Function Groups

1. General Matrices

  • BlasL2GeMV — computes a matrix–vector product: y = α·op(A)·x + β·y (BLAS GEMV)
  • BlasL2GeR — performs a rank-1 matrix update: A ← A + α·x·yᵀ (BLAS GER, GERU)
  • BlasL2GeRC — complex variant with conjugation: A ← A + α·x·conjg(yᵀ) (BLAS GERC)

2. Symmetric Matrices (Real)

  • BlasL2SyMV — computes a matrix–vector product for a symmetric matrix: y = α·A·x + β·y (BLAS SYMV)
  • BlasL2SyR — performs a rank-1 update of a symmetric matrix: A ← A + α·x·xᵀ (BLAS SYR)
  • BlasL2SyR2 — performs a rank-2 update: A ← A + α·(x·yᵀ + y·xᵀ) (BLAS SYR2)

3. Hermitian Matrices (Complex)

  • BlasL2HeMV — computes a matrix–vector product for a Hermitian matrix: y = α·A·x + β·y (BLAS HEMV)
  • BlasL2HeR — performs a rank-1 Hermitian matrix update: A ← A + α·x·conjg(xᵀ) (BLAS HER)
  • BlasL2HeR2 — performs a rank-2 Hermitian update: A ← A + α·x·conjg(yᵀ) + conjg(α)·y·conjg(xᵀ) (BLAS HER2)

4. Triangular Matrices

  • BlasL2TrMV — computes a matrix–vector product using a triangular matrix: y = op(A)·x, where op(A) is A, Aᵀ, or Aᴴ depending on the parameter (BLAS TRMV)

 

L1TrendFilter
BlasL2GeMV