"WD4i" <-
function (x) 
{
    if (!is.matrix(x)) 
        x <- matrix(x, nrow = length(x), ncol = 1)
    n <- nrow(x)
    m <- ncol(x)
    X <- matrix(0, nrow = n, ncol = m)
    X[seq(1, n, 2), ] <- x[1:(n/2), ]
    X[seq(2, n, 2), ] <- x[(n/2 + 1):n, ]
    x <- X
    D4 <- c(0.482962913145, 0.836516303738, 0.224143868042, -0.129409522551)
    D4.le <- matrix(c(0.6033325119, -0.7965435169, 0.03751746045, 
        0.01003722456, 0.6908955318, 0.546392714, 0.4573276599, 
        0.1223510431, -0.3983129977, -0.2587922483, 0.8500881025, 
        0.2274281117, 0, 0, 0.223820357, -0.8366029212, 0, 0, 
        -0.1292227434, 0.4830129218), nrow = 4, ncol = 5, byrow = FALSE)
    D4.r <- c(-0.129409522551, -0.224143868042, 0.836516303738, 
        -0.482962913145)
    D4.re <- matrix(c(0.4431490496, 0.231557595, 0, 0, 0.7675566693, 
        0.4010695194, 0, 0, 0.3749553316, -0.7175799994, 0.2303890438, 
        -0.5398225007, 0.1901514184, -0.3639069596, 0.434896998, 
        0.801422962, -0.1942334074, 0.3717189665, 0.8705087534, 
        -0.2575129195), nrow = 4, ncol = 5, byrow = FALSE)
    D4tr.L <- matrix(0, nrow = 3, ncol = 4)
    D4tr.L[1, ] <- c(D4.le[1, 1], D4.le[2, 1], D4.le[3, 1], D4.le[4, 
        1])
    D4tr.L[2, ] <- c(D4.le[1, 2], D4.le[2, 2], D4.le[3, 2], D4.le[4, 
        2])
    D4tr.L[3, ] <- c(D4.le[1, 3], D4.le[2, 3], D4.le[3, 3], D4.le[4, 
        3])
    D4tr.R <- matrix(0, nrow = 3, ncol = 4)
    D4tr.R[1, ] <- c(D4.re[1, 3], D4.re[2, 3], D4.re[3, 3], D4.re[4, 
        3])
    D4tr.R[2, ] <- c(D4.re[1, 4], D4.re[2, 4], D4.re[3, 4], D4.re[4, 
        4])
    D4tr.R[3, ] <- c(D4.re[1, 5], D4.re[2, 5], D4.re[3, 5], D4.re[4, 
        5])
    if (n == 8) {
        D4tr.t <- matrix(0, nrow = 2, ncol = 4)
        D4tr.t[1, ] <- c(D4.le[3, 4], D4.le[4, 4], D4.re[1, 1], 
            D4.re[2, 1])
        D4tr.t[2, ] <- c(D4.le[3, 5], D4.le[4, 5], D4.re[1, 2], 
            D4.re[2, 2])
    }
    else {
        D4tr.t <- matrix(0, 4, 4)
        D4tr.t[1, ] <- c(D4.le[3, 4], D4.le[4, 4], D4[1], D4.r[1])
        D4tr.t[2, ] <- c(D4.le[3, 5], D4.le[4, 5], D4[2], D4.r[2])
        D4tr.t[3, ] <- c(D4[3], D4.r[3], D4.re[1, 1], D4.re[2, 
            1])
        D4tr.t[4, ] <- c(D4[4], D4.r[4], D4.re[1, 2], D4.re[2, 
            2])
    }
    iD4 <- c(D4[3], D4.r[3], D4[1], D4.r[1])
    iD4.r <- c(D4[4], D4.r[4], D4[2], D4.r[2])
    tmp <- matrix(NA, nrow = n, ncol = m)
    tmp[1:3, ] <- D4tr.L %*% x[1:4, ]
    tmp[(n - 2):n, ] <- D4tr.R %*% x[(n - 3):n, ]
    if (n == 8) {
        tmp[4:5, ] <- D4tr.t %*% x[3:6, ]
    }
    else {
        tmp[4:5, ] <- D4tr.t[1:2, ] %*% x[3:6, ]
        tmp[(n - 4):(n - 3), ] <- D4tr.t[3:4, ] %*% x[(n - 5):(n - 
            2), ]
        indx <- seq(6, (n - 6), 2)
        tmp[indx, ] <- iD4[1] * x[indx - 1, ] + iD4[2] * x[indx, 
            ] + iD4[3] * x[indx + 1, ] + iD4[4] * x[indx + 2, 
            ]
        tmp[indx + 1, ] <- iD4.r[1] * x[indx - 1, ] + iD4.r[2] * 
            x[indx, ] + iD4.r[3] * x[indx + 1, ] + iD4.r[4] * 
            x[indx + 2, ]
    }
    iwt <- tmp
    iwt
}