lapack

compute determinant from LU decomposition in lapack

老子叫甜甜 提交于 2019-12-01 03:33:01
问题 Lapack, most probably, doesn't have any routine for computing determinant. However we can compute it using either LU, QR or SVD decomposition. I prefer to use LU decomposition. Now lapack uses some dgetrf subroutine to factorize a matrix A into PLU format with some IPIV array. I don't have much idea how to deal with this information. To compute the determinant, I just multiply diagonal elements of U matrix. But what is L and U in PLU format and how to extract them. I am programming in C. 回答1:

Rcpparmadillo: can't call Fortran routine “dgebal”?

荒凉一梦 提交于 2019-11-30 23:32:30
I need to use a Fortran routine called dgebal (documentation here ) in my Rcpparmadillo code. I have included the following headers: # include <RcppArmadillo.h> # include <math.h> However, when I try to compile my code using sourceCpp() I get the following error: error: 'dgebal_' was not declared in this scope If I further include <R_ext/Lapack.h> and <R_ext/BLAS.h> , the code compiles without error and runs fine. However the compiler throws a bunch of warnings like this: C:/PROGRA~1/R/R-32~1.3/include/R_ext/BLAS.h:49:64: warning: declaration of 'double dasum_(const int*, const double*, const

Use Emscripten with Fortran: LAPACK binding

ⅰ亾dé卋堺 提交于 2019-11-30 15:07:07
My goal is to use LAPACK with Emscripten. My question is: how to port LAPACK to JS? The are two ways I can think of: CLAPACK to JS where my question is: does anybody know an unofficial version that is later than 3.2.1? And the other way to think of is: how to port FORTRAN to JS? Emscripten is capable of transforming C code to JavaScript. But unfortunately, LAPACK 3.5.0 ( http://www.netlib.org/lapack/ ) is only available in FORTRAN95. The CLAPACK project ( http://www.netlib.org/clapack/ ) is basically what I want: a C version of LAPACK. But this one is outdated; the latest is 3.2.1. F2C only

LAPACK SVD (Singular Value Decomposition)

廉价感情. 提交于 2019-11-30 09:48:04
Do yo know any example to use LAPACK To calculate SVD? The routine dgesdd computes the SVD for a double precision matrix. Do you just need an example of how to use it? Have you tried reading the documentation? An example using the C LAPACK bindings (note that I wrote this just now, and haven't actually tested it. Also note that the exact types for arguments to clapack vary somewhat between platforms so you may need to change int to something else): #include <clapack.h> void SingularValueDecomposition(int m, // number of rows in matrix int n, // number of columns in matrix int lda, // leading

c++11 std::array vs static array vs std::vector

隐身守侯 提交于 2019-11-30 03:38:16
First question, is it a good thing to start using c++11 if I will develop a code for the 3 following years? Then if it is, what is the "best" way to implement a matrix if I want to use it with Lapack? I mean, doing std::vector<std::vector< Type > > Matrix is not easily compatible with Lapack. Up to now, I stored my matrix with Type* Matrix(new Type[N]) (the pointer form with new and delete were important because the size of the array is not given as a number like 5, but as a variable). But with C++11 it is possible to use std::array. According to this site , this container seems to be the best

Use Emscripten with Fortran: LAPACK binding

巧了我就是萌 提交于 2019-11-29 21:27:12
问题 My goal is to use LAPACK with Emscripten. My question is: how to port LAPACK to JS? The are two ways I can think of: CLAPACK to JS where my question is: does anybody know an unofficial version that is later than 3.2.1? And the other way to think of is: how to port FORTRAN to JS? Emscripten is capable of transforming C code to JavaScript. But unfortunately, LAPACK 3.5.0 (http://www.netlib.org/lapack/) is only available in FORTRAN95. The CLAPACK project (http://www.netlib.org/clapack/) is

C++ Memory Efficient Solution for Ax=b Linear Algebra System

陌路散爱 提交于 2019-11-29 20:31:29
I am using Numeric Library Bindings for Boost UBlas to solve a simple linear system. The following works fine, except it is limited to handling matrices A(m x m) for relatively small 'm'. In practice I have a much larger matrix with dimension m= 10^6 (up to 10^7). Is there existing C++ approach for solving Ax=b that uses memory efficiently. #include<boost/numeric/ublas/matrix.hpp> #include<boost/numeric/ublas/io.hpp> #include<boost/numeric/bindings/traits/ublas_matrix.hpp> #include<boost/numeric/bindings/lapack/gesv.hpp> #include <boost/numeric/bindings/traits/ublas_vector2.hpp> // compileable

how to compile lapack so that it can be used correctly during installation of octave?

六眼飞鱼酱① 提交于 2019-11-29 19:47:02
问题 I'm trying to install the latest octave 3.8.1 from source in a cluster running redhat+IBM LSF. I don't have write access to anywhere else except my own home dir, that's why I have to install octave from source. The blas and lapack provided by the cluster does not work so I have to build them by myself. I have now finished compiling both blas and lapack and passed the ./configure , but when I run make, an error is reported as follows: These are steps I used to build my own BLAS and LAPACK .

Incorrect/inconsistent results from zgeev() LAPACK

巧了我就是萌 提交于 2019-11-29 17:25:49
I am attempting to use ZGEEV to calculate eigenvalues and eigenvectors, however am having some trouble with the output being incorrect and also inconsistent when used at different optimization levels. Below is my Fortran code with results at -O1 and -O2 optimization levels. I have also included Python code for comparison. I can only assume that I am calling zgeev() incorrectly somehow, however I am not able to determine how. I believe it is unlikely to be an issue with my LAPACK installation as I have compared the output on two different computers, on Windows and Linux. Fortran code: program

权威的C ++书籍指南和清单

眉间皱痕 提交于 2019-11-29 14:30:57
这篇文章是 社区维基 。 编辑现有答案以改善此职位。 它当前不接受新的答案。 这个问题试图收集每年出版的数十本糟糕的C ++书籍中的珍珠。 与许多其他编程语言不同,这些语言通常是在Internet上的教程中经常使用的,而无需学习一本精心编写的C ++书籍,很少有人能够快速使用C ++。 这样做太大,太复杂。 实际上,它是如此之大和复杂,以至于 有很多非常糟糕的C ++书籍 。 我们不是在谈论不良的风格,而是诸如炫耀 明显的事实错误 和 推广极差的不良编程风格之类的东西 。 请编辑接受的答案,以提供 优质的书籍 和大致的技能水平- 最好 是 在C ++聊天室中 讨论添加内容 之后 。 (如果常规员工不同意建议,他们可能会毫不留情地撤消您的工作。)为您亲自阅读/受益的每本书添加简短的简介/说明。 随时讨论质量,标题等。符合条件的书籍将添加到列表中。 具有C和C ++用户协会(ACCU)的评论的书籍具有该评论的链接。 *注意:常见问题解答和其他资源可以在 C ++标签信息 和 c ++-faq下找到 。 #1楼 初学者 入门,没有以前的编程经验 C ++ Primer *(Stanley Lippman,JoséeLajoie和Barbara E. Moo)( 针对C ++ 11更新 )以1k页的篇幅 对C ++ 进行了非常全面的介绍,它以一种易于访问的格式涵盖了该语言的几乎所有内容