oblas

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 Go to latest Published: May 13, 2020 License: BSD-3-Clause Imports: 6 Imported by: 1

README

Gosl. la/oblas. Wrapper to OpenBLAS

go.dev reference

More information is available in the documentation of this package.

This subpackge implements a light wrapper to OpenBLAS. Therefore, its routines are a little more lower level than the ones in the parent package la.

Check also OpenBLAS.

Documentation

Overview

Package oblas implements lower-level linear algebra routines using OpenBLAS for maximum efficiency. This package uses column-major representation for matrices. 

 Example of col-major data:
           _      _
          |  0  3  |
      A = |  1  4  |            ⇒     a = [0, 1, 2, 3, 4, 5]
          |_ 2  5 _|(m x n)

      a[i+j*m] = A[i][j]

NOTE: the functions here do not check for the limits of indices. Be careful.
      Panic may occur then.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ColMajorCtoSlice added in v1.0.1 

func ColMajorCtoSlice(m, n int, data []complex128) (a [][]complex128)

ColMajorCtoSlice converts col-major matrix to nested slice

func ColMajorToSlice added in v1.0.1 

func ColMajorToSlice(m, n int, data []float64) (a [][]float64)

ColMajorToSlice converts col-major matrix to nested slice

func Daxpy 

func Daxpy(n int, alpha float64, x []float64, incx int, y []float64, incy int)

Daxpy computes constant times a vector plus a vector. 

See: http://www.netlib.org/lapack/explore-html/d9/dcd/daxpy_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-axpy

y += alpha*x + y

func Ddot added in v1.1.0 

func Ddot(n int, x []float64, incx int, y []float64, incy int) (res float64)

Ddot forms the dot product of two vectors. Uses unrolled loops for increments equal to one. 

See: http://www.netlib.org/lapack/explore-html/d5/df6/ddot_8f.html

func Dgeev added in v1.0.1 

func Dgeev(calcVl, calcVr bool, n int, a []float64, lda int, wr []float64, wi, vl []float64, ldvl int, vr []float64, ldvr int)

Dgeev computes for an N-by-N real nonsymmetric matrix A, the eigenvalues and, optionally, the left and/or right eigenvectors. 

See: http://www.netlib.org/lapack/explore-html/d9/d28/dgeev_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-geev

See: https://www.nag.co.uk/numeric/fl/nagdoc_fl26/html/f08/f08naf.html

The right eigenvector v(j) of A satisfies

                 A * v(j) = lambda(j) * v(j)

where lambda(j) is its eigenvalue.

The left eigenvector u(j) of A satisfies

              u(j)**H * A = lambda(j) * u(j)**H

where u(j)**H denotes the conjugate-transpose of u(j).

The computed eigenvectors are normalized to have Euclidean norm
equal to 1 and largest component real.

func Dgemm 

func Dgemm(transA, transB bool, m, n, k int, alpha float64, a []float64, lda int, b []float64, ldb int, beta float64, c []float64, ldc int)

Dgemm performs one of the matrix-matrix operations 

false,false:  C_{m,n} := α ⋅ A_{m,k} ⋅ B_{k,n}  +  β ⋅ C_{m,n}
false,true:   C_{m,n} := α ⋅ A_{m,k} ⋅ B_{n,k}  +  β ⋅ C_{m,n}
true, false:  C_{m,n} := α ⋅ A_{k,m} ⋅ B_{k,n}  +  β ⋅ C_{m,n}
true, true:   C_{m,n} := α ⋅ A_{k,m} ⋅ B_{n,k}  +  β ⋅ C_{m,n}

see: http://www.netlib.org/lapack/explore-html/d7/d2b/dgemm_8f.html

see: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-gemm

   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, and A, B and C are matrices, with op( A )
an m by k matrix,  op( B )  a  k by n matrix and  C an m by n matrix.

func Dgemv 

func Dgemv(trans bool, m, n int, alpha float64, a []float64, lda int, x []float64, incx int, beta float64, y []float64, incy int)

Dgemv performs one of the matrix-vector operations 

See: http://www.netlib.org/lapack/explore-html/dc/da8/dgemv_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-gemv

   y := alpha*A*x + beta*y,   or   y := alpha*A**T*x + beta*y,

where alpha and beta are scalars, x and y are vectors and A is an
m by n matrix.
   trans=false     y := alpha*A*x + beta*y.

   trans=true      y := alpha*A**T*x + beta*y.

func Dger added in v1.1.0 

func Dger(m, n int, alpha float64, x []float64, incx int, y []float64, incy int, a []float64, lda int)

Dger performs the rank 1 operation 

See: http://www.netlib.org/lapack/explore-html/dc/da8/dger_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-ger

  A := alpha*x*y**T + A,

where alpha is a scalar, x is an m element vector, y is an n element vector and A is an m by n matrix.

func Dgesv 

func Dgesv(n, nrhs int, a []float64, lda int, ipiv []int32, b []float64, ldb int)

Dgesv computes the solution to a real system of linear equations. 

See: http://www.netlib.org/lapack/explore-html/d8/d72/dgesv_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-gesv

The system is:

   A * X = B,

where A is an N-by-N matrix and X and B are N-by-NRHS matrices.

The LU decomposition with partial pivoting and row interchanges is
used to factor A as

   A = P * L * U,

where P is a permutation matrix, L is unit lower triangular, and U is
upper triangular.  The factored form of A is then used to solve the
system of equations A * X = B.

NOTE: matrix 'a' will be modified

func Dgesvd 

func Dgesvd(jobu, jobvt rune, m, n int, a []float64, lda int, s []float64, u []float64, ldu int, vt []float64, ldvt int, superb []float64)

Dgesvd computes the singular value decomposition (SVD) of a real M-by-N matrix A, optionally computing the left and/or right singular vectors. 

See: http://www.netlib.org/lapack/explore-html/d8/d2d/dgesvd_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-gesvd

The SVD is written

     A = U * SIGMA * transpose(V)

where SIGMA is an M-by-N matrix which is zero except for its
min(m,n) diagonal elements, U is an M-by-M orthogonal matrix, and
V is an N-by-N orthogonal matrix.  The diagonal elements of SIGMA
are the singular values of A; they are real and non-negative, and
are returned in descending order.  The first min(m,n) columns of
U and V are the left and right singular vectors of A.

Note that the routine returns V**T, not V.

NOTE: matrix 'a' will be modified

func Dgetrf 

func Dgetrf(m, n int, a []float64, lda int, ipiv []int32)

Dgetrf computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges. 

See: http://www.netlib.org/lapack/explore-html/d3/d6a/dgetrf_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-getrf

The factorization has the form
   A = P * L * U
where P is a permutation matrix, L is lower triangular with unit
diagonal elements (lower trapezoidal if m > n), and U is upper
triangular (upper trapezoidal if m < n).

This is the right-looking Level 3 BLAS version of the algorithm.

NOTE: (1) matrix 'a' will be modified
      (2) ipiv indices are 1-based (i.e. Fortran)

func Dgetri 

func Dgetri(n int, a []float64, lda int, ipiv []int32)

Dgetri computes the inverse of a matrix using the LU factorization computed by DGETRF. 

See: http://www.netlib.org/lapack/explore-html/df/da4/dgetri_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-getri

This method inverts U and then computes inv(A) by solving the system
inv(A)*L = inv(U) for inv(A).

func Dpotrf 

func Dpotrf(up bool, n int, a []float64, lda int)

Dpotrf computes the Cholesky factorization of a real symmetric positive definite matrix A. 

See: http://www.netlib.org/lapack/explore-html/d0/d8a/dpotrf_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-potrf

The factorization has the form

   A = U**T * U,  if UPLO = 'U'

or

   A = L  * L**T,  if UPLO = 'L'

where U is an upper triangular matrix and L is lower triangular.

This is the block version of the algorithm, calling Level 3 BLAS.

func Dscal added in v1.1.0 

func Dscal(n int, alpha float64, x []float64, incx int)

Dscal scales a vector by a constant. Uses unrolled loops for increment equal to 1. 

See: http://www.netlib.org/lapack/explore-html/d4/dd0/dscal_8f.html

func Dsyrk 

func Dsyrk(up, trans bool, n, k int, alpha float64, a []float64, lda int, beta float64, c []float64, ldc int)

Dsyrk performs one of the symmetric rank k operations 

See: http://www.netlib.org/lapack/explore-html/dc/d05/dsyrk_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-syrk

   C := alpha*A*A**T + beta*C,

or

   C := alpha*A**T*A + beta*C,

where  alpha and beta  are scalars, C is an  n by n  symmetric matrix
and  A  is an  n by k  matrix in the first case and a  k by n  matrix
in the second case.

func EigenvecsBuild added in v1.0.1 

func EigenvecsBuild(vv []complex128, wr, wi, v []float64)

EigenvecsBuild builds complex eigenvectros created by Dgeev function 

INPUT:
 wr, wi -- real and imag parts of eigenvalues
 v      -- left or right eigenvectors from Dgeev
OUTPUT:
 vv -- complex version of left or right eigenvector [pre-allocated]
NOTE (no checks made)
 n = len(wr) = len(wi) = len(v)
 2 * n = len(vv)

func EigenvecsBuildBoth added in v1.0.1 

func EigenvecsBuildBoth(vvl, vvr []complex128, wr, wi, vl, vr []float64)

EigenvecsBuildBoth builds complex left and right eigenvectros created by Dgeev function 

INPUT:
 wr, wi -- real and imag parts of eigenvalues
 vl, vr -- left and right eigenvectors from Dgeev
OUTPUT:
 vvl, vvr -- complex version of left and right eigenvectors [pre-allocated]
NOTE (no checks made)
 n = len(wr) = len(wi) = len(vl) = len(vr)
 2 * n = len(vvl) = len(vvr)

func ExtractCol added in v1.0.1 

func ExtractCol(j, m, n int, A []float64) (colj []float64)

ExtractCol extracts j column from (m,n) col-major matrix

func ExtractColC added in v1.0.1 

func ExtractColC(j, m, n int, A []complex128) (colj []complex128)

ExtractColC extracts j column from (m,n) col-major matrix (complex version)

func ExtractRow added in v1.0.1 

func ExtractRow(i, m, n int, A []float64) (rowi []float64)

ExtractRow extracts i row from (m,n) col-major matrix

func ExtractRowC added in v1.0.1 

func ExtractRowC(i, m, n int, A []complex128) (rowi []complex128)

ExtractRowC extracts i row from (m,n) col-major matrix (complex version)

func GetJoinComplex added in v1.0.1 

func GetJoinComplex(vReal, vImag []float64) (v []complex128)

GetJoinComplex joins real and imag parts of array

func GetSplitComplex added in v1.0.1 

func GetSplitComplex(v []complex128) (vReal, vImag []float64)

GetSplitComplex splits real and imag parts of array

func JoinComplex added in v1.0.1 

func JoinComplex(v []complex128, vReal, vImag []float64)

JoinComplex joins real and imag parts of array

func PrintColMajor added in v1.0.1 

func PrintColMajor(m, n int, data []float64, nfmt string) (l string)

PrintColMajor prints matrix (without commas or brackets)

func PrintColMajorC added in v1.0.1 

func PrintColMajorC(m, n int, data []complex128, nfmtR, nfmtI string) (l string)

PrintColMajorC prints matrix (without commas or brackets). NOTE: if non-empty, nfmtI must have '+' e.g. %+g

func PrintColMajorCgo added in v1.0.1 

func PrintColMajorCgo(m, n int, data []complex128, nfmtR, nfmtI string) (l string)

PrintColMajorCgo prints matrix in Go format NOTE: if non-empty, nfmtI must have '+' e.g. %+g

func PrintColMajorCpy added in v1.0.1 

func PrintColMajorCpy(m, n int, data []complex128, nfmtR, nfmtI string) (l string)

PrintColMajorCpy prints matrix in Python format NOTE: if non-empty, nfmtI must have '+' e.g. %+g

func PrintColMajorGo added in v1.0.1 

func PrintColMajorGo(m, n int, data []float64, nfmt string) (l string)

PrintColMajorGo prints matrix in Go format

func PrintColMajorPy added in v1.0.1 

func PrintColMajorPy(m, n int, data []float64, nfmt string) (l string)

PrintColMajorPy prints matrix in Python format

func SetNumThreads 

func SetNumThreads(n int)

SetNumThreads sets the number of threads in OpenBLAS

func SliceToColMajor added in v1.0.1 

func SliceToColMajor(a [][]float64) (data []float64)

SliceToColMajor converts nested slice into an array representing a col-major matrix 

Example:
          _      _
         |  0  3  |
     a = |  1  4  |            ⇒     data = [0, 1, 2, 3, 4, 5]
         |_ 2  5 _|(m x n)

     data[i+j*m] = a[i][j]

NOTE: make sure to have at least 1x1 item

func SliceToColMajorC added in v1.0.1 

func SliceToColMajorC(a [][]complex128) (data []complex128)

SliceToColMajorC converts nested slice into an array representing a col-major matrix of complex numbers. 

Example:
          _            _
         |  0+0i  3+3i  |
     a = |  1+1i  4+4i  |          ⇒   data = [0+0i, 1+1i, 2+2i, 3+3i, 4+4i, 5+5i]
         |_ 2+2i  5+5i _|(m x n)

     data[i+j*m] = a[i][j]

NOTE: make sure to have at least 1x1 item

func SplitComplex added in v1.0.1 

func SplitComplex(vReal, vImag []float64, v []complex128)

SplitComplex splits real and imag parts of array

func Zaxpy 

func Zaxpy(n int, alpha complex128, x []complex128, incx int, y []complex128, incy int)

Zaxpy computes constant times a vector plus a vector. 

See: http://www.netlib.org/lapack/explore-html/d7/db2/zaxpy_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-axpy

y += alpha*x + y

func Zgemm 

func Zgemm(transA, transB bool, m, n, k int, alpha complex128, a []complex128, lda int, b []complex128, ldb int, beta complex128, c []complex128, ldc int)

Zgemm performs one of the matrix-matrix operations 

see: http://www.netlib.org/lapack/explore-html/d7/d76/zgemm_8f.html

see: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-gemm

   C := alpha*op( A )*op( B ) + beta*C,

where  op( X ) is one of

   op( X ) = X   or   op( X ) = X**T   or   op( X ) = X**H,

alpha and beta are scalars, and A, B and C are matrices, with op( A )
an m by k matrix,  op( B )  a  k by n matrix and  C an m by n matrix.

func Zgemv 

func Zgemv(trans bool, m, n int, alpha complex128, a []complex128, lda int, x []complex128, incx int, beta complex128, y []complex128, incy int)

Zgemv performs one of the matrix-vector operations. 

See: http://www.netlib.org/lapack/explore-html/db/d40/zgemv_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-gemv

   y := alpha*A*x + beta*y,   or   y := alpha*A**T*x + beta*y,   or

   y := alpha*A**H*x + beta*y,

where alpha and beta are scalars, x and y are vectors and A is an
m by n matrix.

func Zgesv 

func Zgesv(n, nrhs int, a []complex128, lda int, ipiv []int32, b []complex128, ldb int)

Zgesv computes the solution to a complex system of linear equations. 

See: http://www.netlib.org/lapack/explore-html/d1/ddc/zgesv_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-gesv

The system is:

   A * X = B,

where A is an N-by-N matrix and X and B are N-by-NRHS matrices.

The LU decomposition with partial pivoting and row interchanges is
used to factor A as

   A = P * L * U,

where P is a permutation matrix, L is unit lower triangular, and U is
upper triangular.  The factored form of A is then used to solve the
system of equations A * X = B.

NOTE: matrix 'a' will be modified

func Zgesvd 

func Zgesvd(jobu, jobvt rune, m, n int, a []complex128, lda int, s []float64, u []complex128, ldu int, vt []complex128, ldvt int, superb []float64)

Zgesvd computes the singular value decomposition (SVD) of a complex M-by-N matrix A, optionally computing the left and/or right singular vectors. 

See: http://www.netlib.org/lapack/explore-html/d6/d42/zgesvd_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-gesvd

The SVD is written

     A = U * SIGMA * conjugate-transpose(V)

where SIGMA is an M-by-N matrix which is zero except for its
min(m,n) diagonal elements, U is an M-by-M unitary matrix, and
V is an N-by-N unitary matrix.  The diagonal elements of SIGMA
are the singular values of A; they are real and non-negative, and
are returned in descending order.  The first min(m,n) columns of
U and V are the left and right singular vectors of A.

Note that the routine returns V**H, not V.

NOTE: matrix 'a' will be modified

func Zgetrf 

func Zgetrf(m, n int, a []complex128, lda int, ipiv []int32)

Zgetrf computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges. 

See: http://www.netlib.org/lapack/explore-html/dd/dd1/zgetrf_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-getrf

The factorization has the form
   A = P * L * U
where P is a permutation matrix, L is lower triangular with unit
diagonal elements (lower trapezoidal if m > n), and U is upper
triangular (upper trapezoidal if m < n).

This is the right-looking Level 3 BLAS version of the algorithm.

NOTE: (1) matrix 'a' will be modified
      (2) ipiv indices are 1-based (i.e. Fortran)

func Zgetri 

func Zgetri(n int, a []complex128, lda int, ipiv []int32)

Zgetri computes the inverse of a matrix using the LU factorization computed by Zgetrf. 

See: http://www.netlib.org/lapack/explore-html/d0/db3/zgetri_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-getri

This method inverts U and then computes inv(A) by solving the system
inv(A)*L = inv(U) for inv(A).

func Zherk 

func Zherk(up, trans bool, n, k int, alpha float64, a []complex128, lda int, beta float64, c []complex128, ldc int)

Zherk performs one of the hermitian rank k operations 

See: http://www.netlib.org/lapack/explore-html/d1/db1/zherk_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-herk

   C := alpha*A*A**H + beta*C,

or

   C := alpha*A**H*A + beta*C,

where  alpha and beta  are  real scalars,  C is an  n by n  hermitian
matrix and  A  is an  n by k  matrix in the  first case and a  k by n
matrix in the second case.

func Zpotrf 

func Zpotrf(up bool, n int, a []complex128, lda int)

Zpotrf computes the Cholesky factorization of a complex Hermitian positive definite matrix A. 

See: http://www.netlib.org/lapack/explore-html/d1/db9/zpotrf_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-potrf

The factorization has the form

   A = U**H * U,  if UPLO = 'U'

or

   A = L  * L**H,  if UPLO = 'L'

where U is an upper triangular matrix and L is lower triangular.

This is the block version of the algorithm, calling Level 3 BLAS.

func Zsyrk 

func Zsyrk(up, trans bool, n, k int, alpha complex128, a []complex128, lda int, beta complex128, c []complex128, ldc int)

Zsyrk performs one of the symmetric rank k operations 

See: http://www.netlib.org/lapack/explore-html/de/d54/zsyrk_8f.html

See: https://software.intel.com/en-us/mkl-developer-reference-c-cblas-syrk

   C := alpha*A*A**T + beta*C,

or

   C := alpha*A**T*A + beta*C,

where  alpha and beta  are scalars,  C is an  n by n symmetric matrix
and  A  is an  n by k  matrix in the first case and a  k by n  matrix
in the second case.

Types

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