Understanding and Resolving Matrix Multiplication Errors in RcppArmadillo on Windows Platforms

Understanding the Error in RcppArmadillo Matrix Multiplication under Windows

Introduction

RcppArmadillo is a popular package for using Armadillo, a high-performance linear algebra library, from within R. While it provides an efficient way to perform various matrix operations, users may encounter errors when compiling their code on Windows platforms.

In this article, we will delve into the issue of matrix multiplication in RcppArmadillo failing under Windows and explore its causes and solutions.

The Problem

The error “unable to load shared object ‘C:/Users/[Username]/AppData/Local/Temp/RtmpG6H80X/sourceCpp-x86_64-w64-mingw32-0.12.19/sourcecpp_40b04b2c2bcf/sourceCpp_4.dll’: LoadLibrary failure: The specified procedure could not be found” indicates that the RcppArmadillo package is unable to find the BLAS library, which is required for matrix multiplication operations.

Background

BLAS (Basic Linear Algebra Subprograms) is a set of software routines for performing basic linear algebra operations. It is widely used in various scientific and engineering applications, including numerical analysis, data analysis, and machine learning.

RcppArmadillo relies on the BLAS library to perform matrix multiplication and other linear algebra operations. The package uses the BLAS library to optimize performance and efficiency.

Causing Factors

There are several factors that may cause the RcppArmadillo matrix multiplication error under Windows:

The BLAS library is not correctly set in the system environment path.
The RcppArmadillo package is installed from source, which requires manual configuration of the BLAS library.
The binary version of RcppArmadillo is installed, which may not provide feedback about missing BLAS libraries.

Solution

To resolve this issue, follow these steps:

Download precompiled binary packages: Download precompiled binary packages of OpenBLAS at Here.
Extract the package: Extract the package to a directory like C:\LIBS\OpenBLAS-v0.2.15-Win64-int32.
Add the bin directory to the system path: Add the bin directory of the extracted package to your system’s PATH environment variable.
[Optional] Create a new environment variable: If you want to ensure that the BLAS library is used consistently across different applications, create a new environment variable called BLAS_LIBS, which points to the bin directory of the OpenBLAS package.

Example

Here is an example of how to add the bin directory to the system path in Windows:

Right-click on “This PC” or “Computer” and select “Properties.”
Click on “Advanced system settings” on the left side.
Click on “Environment Variables.”
Under “System Variables,” click “New.”
In the “Variable name” field, enter BLAS_LIBS.
In the “Variable value” field, enter the path to the bin directory of the OpenBLAS package (e.g., C:\LIBS\OpenBLAS-v0.2.15-Win64-int32\bin).
Click “OK” to close all the windows.

Conclusion

In this article, we discussed the issue of matrix multiplication in RcppArmadillo failing under Windows and explored its causes and solutions. By following the steps outlined above, you should be able to resolve this issue and successfully compile your RcppArmadillo code on Windows platforms.