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Questions tagged [lapack]

LAPACK (Linear Algebra PACKage) is a software library package to solve linear algebra equations. LAPACK is written in Fortran 90.

LAPACK provides routines for solving systems of simultaneous linear equations, least-squares solutions of linear systems of equations, eigenvalue problems, and singular value problems. LAPACK is written in Fortran 90.

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Are there native C++ (not C) interfaces for Blas and Lapack libraries?

Currently, there are: cblas which is shipped with blas, lapacke which is shipped with lapack, however, these are C interfaces. Obviously, you can use them in a C++ code, but you do not get all the benefits you would get if these interfaces were…
Picaud Vincent
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What is the use of the WORK parameters in LAPACK routines?

I am computing an eigenvalue decomposition of a symmetric matrix with scipy.linalg.cython_lapack.syev. From the doc I found, I need to pass an array called WORK: WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO…
P. Camilleri
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Linking LAPACK from Intel MKL with gfortran

I have a problem to link lapack to fortran example program. Here is the program example.f95 Program LinearEquations ! solving the matrix equation A*x=b using LAPACK Implicit none ! declarations double precision :: A(3,3), b(3) integer :: i,…
Vlada
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Solving a constrained system of linear equations

I have a system of equations of the form y=Ax+b where y, x and b are n×1 vectors and A is a n×n (symmetric) matrix. So here is the wrinkle. Not all of x is unknown. Certain rows of x are specified and the corresponding rows of y are unknown. Below…
John Alexiou
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Rcpparmadillo: can't call Fortran routine "dgebal"?

I need to use a Fortran routine called dgebal (documentation here) in my Rcpparmadillo code. I have included the following headers: # include # include However, when I try to compile my code using sourceCpp() I get the…
aenima
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Lapack gcc on Mac OS

I am trying to compile my C++ code with gcc against the Accelerate framework in order to make use of Lapack. However I receive the following error…
Faser
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LAPACKE on Accelerate Framework

I am developing a linear algebra based tool in C++ that allows users to link to OpenBLAS/ATLAS/Intel MKL on different operating systems. This is all well and good on Windows and Linux, but I would prefer to allow OS X users to link also to…
The_Anomaly
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Error in linking gfortran to LAPACK and BLAS

I have installed LAPACK and BLAS from Synaptic package manager in Ubuntu. whereis libblas libblas: /usr/lib/libblas.so /usr/lib/libblas.a /usr/lib/libblas whereis liblapack liblapack: /usr/lib/liblapack.a /usr/lib/liblapack.so When I try to…
Rajarshi
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Can't find liblapack.so.3 in ubuntu 12.04

When I ran a matlab code in ubuntu 12.04, an error occurred: liblapack.so.3: cannot open shared object file: No such file or directory Then I installed lapack and libatlas, but only found liblapack.so.3gf instead of liblapack.so.3 in /usr/lib.…
qqwqert007
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Is sparse BLAS not included in BLAS?

I have a working LAPACK implementation and that, as far as I read, contains BLAS. I want to use SPARSE BLAS and as far as I understand this website, SPARSE BLAS is part of BLAS. But when I tried to run the code below from the sparse blas manual…
Ludi
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Compile numpy WITHOUT Intel MKL/BLAS/ATLAS/LAPACK

I am using py2exe to convert a script which uses numpy and am getting a very large resulting folder, and it seems a lot of the large files are from parts of the numpy package that I'm not using, such as numpy.linalg. To reduce the size of folder…
Siwel
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Installing BLAS on a mac OS X Yosemite

I'm trying to Install BLAS on my Mac, but every time I run make I get this error (shown below the link). I was trying to follow the instructions on this website: gfortran -O3 -c isamax.f -o isamax.o make: gfortran: No such file or directory make:…
Bella Pagano
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How to get the Q from the QR factorization output?

DGEQRF and SGEQRF from LAPACK return the Q part of the QR factorization in a packed format. Unpacking it seems to require O(k^3) steps (k low-rank products), and doesn't seem to be very straightforward. Plus, the numerical stability of doing k…
MWB
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Why is there a blas subroutine (ISAMAX) for argmax abs but none for argmax?

Why is there a blas subroutine ISAMAX for argmax abs but not for argmax ? In C++ using std::max_element with compiler optimisation flag -O3 I am getting speeds comparable to blas_isamax (16 ms vs 9 ms), so at the moment my question is more out of…
newling
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Docker images with architecture optimisation?

Some libraries such as BLAS/LAPACK or certain optimisation libraries get optimised for the local machine architecture upon compilation time. Lets take OpenBlas as an example. There exist two ways to create a Docker container with OpenBlas: Use a…
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