Estrin's Scheme - Description of The Algorithm

Description of The Algorithm

Given an arbitrary polynomial Pn(x)= C0 + C1x + C2x2 + C3x3 + ... + Cnxn one can isolate sub-expressions of the form (A + Bx) and of the form x2n.

Rewritten using Estrin's scheme we get Pn(x) = (C0 + C1x) + (C2 + C3x) x2 + ((C4 + C5x) + (C6 + C7x) x2))x4 + ...

x2n can be evaluated once and kept until no longer required. As is evident from looking at this expression there are many sub-expression that may be evaluated in parallel.

The sub-expressions of form (A+ Bx) can be evaluated using a native multiply–accumulate instruction on some architectures, an advantage that is shared with the Horner scheme.

Read more about this topic:  Estrin's Scheme

Famous quotes containing the words description of the, description of and/or description:

    Everything to which we concede existence is a posit from the standpoint of a description of the theory-building process, and simultaneously real from the standpoint of the theory that is being built. Nor let us look down on the standpoint of the theory as make-believe; for we can never do better than occupy the standpoint of some theory or other, the best we can muster at the time.
    Willard Van Orman Quine (b. 1908)

    Do not require a description of the countries towards which you sail. The description does not describe them to you, and to- morrow you arrive there, and know them by inhabiting them.
    Ralph Waldo Emerson (1803–1882)

    The great object in life is Sensation—to feel that we exist, even though in pain; it is this “craving void” which drives us to gaming, to battle, to travel, to intemperate but keenly felt pursuits of every description whose principal attraction is the agitation inseparable from their accomplishment.
    George Gordon Noel Byron (1788–1824)