Taming the Beast: Conquering the “Intel oneMKL ERROR: Parameter 6 was incorrect on entry to DGELSD” Error

Are you tired of encountering the frustrating “Intel oneMKL ERROR: Parameter 6 was incorrect on entry to DGELSD” error? Do you feel like you’ve tried everything to resolve the issue, but to no avail? Fear not, dear reader, for we’re about to embark on a journey to slay this beast and get your Intel oneMKL-based applications running smoothly.

What is DGELSD, anyway?

Before we dive into the solution, let’s take a step back and understand what DGELSD is. DGELSD is a subroutine from the LAPACK library, which is used for linear algebra operations. Specifically, DGELSD is used to solve systems of linear equations of the form AX = B, where A is a matrix, X is the solution, and B is the right-hand side vector. Intel oneMKL, a math kernel library, provides an optimized implementation of LAPACK, including the DGELSD subroutine.

The Error: “Parameter 6 was incorrect on entry to DGELSD”

The error message “Parameter 6 was incorrect on entry to DGELSD” typically occurs when the input parameters to the DGELSD subroutine are invalid or inconsistent. This can happen due to various reasons, such as:

• Incorrect matrix dimensions
• Invalid input data types
• Insufficient memory allocation
• Mismatched matrix formats (e.g., row-major vs. column-major)

Troubleshooting Steps

To resolve the error, follow these systematic troubleshooting steps:

1. Verify the matrix dimensions

   Ensure that the matrix dimensions (number of rows, columns, and leading dimension) are correct and consistent across all input parameters. Double-check that the matrix is not singular (i.e., has no zero rows or columns).

2. Check the input data types

   Confirm that the input data types match the requirements of the DGELSD subroutine. For example, if the matrix A is a double-precision real matrix, ensure that the input data is of type double precision.

3. Verify memory allocation

   Make sure that sufficient memory is allocated for the input matrices and vectors. Use tools like Valgrind or AddressSanitizer to detect memory-related issues.

4. Check the matrix format

   Ensure that the matrix format (row-major or column-major) is consistent across all input parameters. Intel oneMKL expects column-major format by default.

5. Review the DGELSD documentation

   Consult the DGELSD documentation and Intel oneMKL documentation to ensure that you’re using the correct syntax and input parameters.

Example Code Snippet

#include <mkl_lapacke.h>

int main() {
  // Define the matrix dimensions
  int m = 3, n = 3, lda = m, ldb = m;

  // Allocate memory for the matrices
  double *A = (double *)malloc(lda * n * sizeof(double));
  double *B = (double *)malloc(ldb * n * sizeof(double));

  // Initialize the matrices
  // ...

  // Call DGELSD
  LAPACK_dgelsd(&m, &n, &lda, A, &ldb, B, &info);

  // Check the info parameter for errors
  if (info <> 0) {
    printf("Error: %d\n", info);
    return 1;
  }

  // Deallocate memory
  free(A);
  free(B);

  return 0;
}

In this example, the matrix A is a 3×3 double-precision real matrix, and the matrix B is also a 3×3 double-precision real matrix. The leading dimension of A (lda) and B (ldb) is set to m, which is the number of rows. The DGELSD subroutine is called with the correct input parameters, and the info parameter is checked for errors.

Common Pitfalls and Solutions

Here are some common pitfalls and solutions to help you avoid the “Parameter 6 was incorrect on entry to DGELSD” error:

Pitfall	Solution
Incorrect matrix dimensions	Verify the matrix dimensions and ensure they match the requirements of the DGELSD subroutine.
Invalid input data types	Check the input data types and ensure they match the requirements of the DGELSD subroutine.
Insufficient memory allocation	Verify that sufficient memory is allocated for the input matrices and vectors.
Mismatched matrix formats	Ensure that the matrix format (row-major or column-major) is consistent across all input parameters.
Incorrect leading dimension	Verify that the leading dimension is correct and matches the requirements of the DGELSD subroutine.

Conclusion

In conclusion, the “Intel oneMKL ERROR: Parameter 6 was incorrect on entry to DGELSD” error can be resolved by carefully following the troubleshooting steps outlined above. By verifying the matrix dimensions, input data types, memory allocation, and matrix format, you can ensure that the DGELSD subroutine is called with correct and consistent input parameters. Remember to consult the DGELSD documentation and Intel oneMKL documentation for detailed information on the subroutine’s requirements and usage.

With these steps and guidelines, you’ll be well on your way to conquering the “Parameter 6 was incorrect on entry to DGELSD” error and unleashing the full potential of Intel oneMKL in your applications.

Additional Resources

For further assistance, refer to the following resources:

• Intel oneMKL Documentation: DGELSD
• LAPACK Documentation: DGELSD
• Intel Math Kernel Library (MKL) Optimization Guide

By following the steps outlined in this article and consulting the additional resources provided, you’ll be well-equipped to tackle the “Parameter 6 was incorrect on entry to DGELSD” error and optimize your Intel oneMKL-based applications for peak performance.

Frequently Asked Question

Stuck with the infamous “Intel oneMKL ERROR: Parameter 6 was incorrect on entry to DGELSD” error? Don’t worry, we’ve got you covered! Here are some frequently asked questions to help you troubleshoot and solve this frustrating issue: