Backward Error Analysis and Numerical Software

11/09/00


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Table of contents

Backward Error Analysis and Numerical Software

Plan of Talk

Stability

Example - Sample Variance

Error Analysis

Example

Example (cont’d)

Diapositive PPT

Example (cont’d)

Example (cont’d)

Example (cont’d)

Example (cont’d)

Componentwise and Normwise

Condition

Example

Diapositive PPT

Condition Number for Linear Equations

Condition and Error Analysis

Example

Backward Error as Perturbations in the Data

Backward Error as … (cont’d)

Example

Backward Error Analysis

Backward Error and Perturbation Analysis

The Purpose of Error Analysis

Diapositive PPT

LAPACK and Error Bounds

The BLAS, LAPACK and ScaLAPACK

The Three Levels of BLAS

Why Higher Level BLAS?

BLAS for Performance

Publication of the Specifications of the BLAS

LAPACK

Benefits of LAPACK

Diapositive PPT

Diapositive PPT

Diapositive PPT

Performance Improvements

Error Bounds in LAPACK

Error Bounds in LAPACK: Example 1

Error Bounds in LAPACK: Example 2

Error Bounds in LAPACK: Example 2 (cont’d)

Error Bounds in LAPACK: Example 2 (cont’d)

Diapositive PPT

LAPACK - Summary

ScaLAPACK

Diapositive PPT

ScaLAPACK Structure

ScaLAPACK Summary

Hierarchy of Building Blocks

Developments Since Wilkinson

Diagonal Matrix Example

Backward Errors in Other Areas

What to do if Software does not Provide Estimates?

PRECISE

Quality of Reliable Software

References

Closing Remarks

Author:Sven Hammarling