From 50f694b7a070631660ad35f7f46faf9c535480de Mon Sep 17 00:00:00 2001
From: Luc Maisonobe A symmetrical m × m matrix A can be written as the product of three matrices:
* A = Q × T × QT with Q an orthogonal matrix and T a symmetrical
- * tri-diagonal matrix. Both Q and T are m × m matrices. Transformation to tri-diagonal shape is often not a goal by itself, but it is
+ * tridiagonal matrix. Both Q and T are m × m matrices. This implementation only uses the upper part of the matrix, the part below the
+ * diagonal is not accessed at all. Transformation to tridiagonal shape is often not a goal by itself, but it is
* an intermediate step in more general decomposition algorithms like {@link
- * EigenValuesDecomposition Eigen Values Decomposition}. This class is therefore
- * intended for internal use by the library and is not public. As a consequence of
- * this explicitly limited scope, many methods directly returns references to
- * internal arrays, not copies.
The specified matrix is assumed to be symmetrical without any check. * Only the upper triangular part of the matrix is used.
* @param matrix the symmetrical matrix to transform. @@ -67,7 +68,7 @@ class TriDiagonalTransformer implements Serializable { public TriDiagonalTransformer(RealMatrix matrix) throws InvalidMatrixException { if (!matrix.isSquare()) { - throw new InvalidMatrixException("transformation to tri-diagonal requires that the matrix be square"); + throw new InvalidMatrixException("transformation to tridiagonal requires that the matrix be square"); } final int m = matrix.getRowDimension(); @@ -140,7 +141,7 @@ class TriDiagonalTransformer implements Serializable { } /** - * Returns the tri-diagonal matrix T of the transform. + * Returns the tridiagonal matrix T of the transform. * @return the T matrix */ public RealMatrix getT() { @@ -201,7 +202,7 @@ class TriDiagonalTransformer implements Serializable { } /** - * Transform original matrix to tri-diagonal form. + * Transform original matrix to tridiagonal form. *Transformation is done using Householder transforms.
*/ private void transform() {