Delta-rational chord: Difference between revisions
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which can be plugged back into the error formula to obtain the error. (We multiply the target DR chord by x in order to compare it to the approximation on the same isodifferential series.) | which can be plugged back into the error formula to obtain the error. (We multiply the target DR chord by x in order to compare it to the approximation on the same isodifferential series.) This error measure is invariant under scaling the target delta signature, but not under scaling the approximation, which is why we require the approximating chord to start on 1. | ||
This error measure is called '''naive least-squares error''' (NLS error). This error measure does not form a metric on the set of delta signatures with a fixed number of terms, since it is not symmetric. | This error measure is called '''naive least-squares error''' (NLS error). This error measure does not form a metric on the set of delta signatures with a fixed number of terms, since it is not symmetric. | ||