/**
* This determines the degree of the
- * Chebyshev polynomial.
+ * Chebyshev polynomial. The degree
+ * of the polynomial gives the number
+ * of matrix-vector products to be
+ * performed for one application of
+ * the vmult() operation.
*/
unsigned int degree;
double min_diagonal;
/**
- * This flag let the preconditioner
- * start at a nonzero value when
- * generating the Chebyshev
- * polynomial.
+ * When this flag is set to
+ * <tt>true</tt>, it enables the
+ * method <tt>vmult(dst, src)</tt> to
+ * use non-zero data in the vector
+ * <tt>dst</tt>, appending to it the
+ * Chebyshev corrections. This can be
+ * useful in some situations
+ * (e.g. when used for high-frequency
+ * error smoothing), but not the way
+ * the solver classes expect a
+ * preconditioner to work (where one
+ * ignores the content in
+ * <tt>dst</tt> for the
+ * preconditioner application). The
+ * user should really know what she
+ * is doing when touching this flag.
*/
- double nonzero_starting;
+ bool nonzero_starting;
};
/**