Nile River Minima

An orthonormal basis for the discrete wavelet transform may be
characterized via a disjoint partitioning of the frequency axis that
covers *[0,1/2)*. This subroutine produces an
orthonormal basis from a full wavelet packet tree.

1 | ```
ortho.basis(xtree)
``` |

`xtree` |
is a vector whose entries are associated with a wavelet packet tree. |

A wavelet packet tree is a binary tree of Boolean variables. Parent nodes are removed if any of their children exist.

Boolean vector describing the orthonormal basis for the DWPT.

B. Whitcher

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ```
data(japan)
J <- 4
wf <- "mb8"
japan.mra <- mra(log(japan), wf, J, boundary="reflection")
japan.nomean <-
ts(apply(matrix(unlist(japan.mra[-(J+1)]), ncol=J, byrow=FALSE), 1, sum),
start=1955, freq=4)
japan.nomean2 <- ts(japan.nomean[42:169], start=1965.25, freq=4)
plot(japan.nomean2, type="l")
japan.dwpt <- dwpt(japan.nomean2, wf, 6)
japan.basis <-
ortho.basis(portmanteau.test(japan.dwpt, p=0.01, type="other"))
# Not implemented yet
# par(mfrow=c(1,1))
# plot.basis(japan.basis)
``` |

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