rmlapsvm_compact = function(K, L, y, gamma = 0.5, lambda, lambda_I, epsilon = 1e-6,
eig_tol_D = 0, eig_tol_I = .Machine$double.eps, epsilon_D = 1e-6, epsilon_I = 0)
{
out = list()
# The labeled sample size, unlabeled sample size, the number of classes and dimension of QP problem
y_temp = factor(y)
levs = levels(y_temp)
attr(levs, "type") = class(y)
y_int = as.integer(y_temp)
n_class = length(levs)
n = nrow(K)
n_l = length(y_int)
n_u = n - n_l
qp_dim = n_l * n_class
code_mat = code_rmsvm(y_int)
In = code_mat$In
vmatj = code_mat$vmatj
umatj = code_mat$umatj
Hmatj = code_mat$Hmatj
y_index = code_mat$y_index
J = cbind(diag(n_l), matrix(0, n_l, n_u))
# inv_LK = solve(diag(n_l * lambda, n) + n_l * lambda_I / n^2 * (L %*% K))
# LK = fixit(diag(n_l * lambda, n) + n_l * lambda_I / n^2 * (L %*% K), eig_tol_I)
# inv_LK = chol2inv(chol(LK))
# K = fixit(K, eig_tol_D)
# inv_LK = inverse(diag(n_l * lambda, n) + n_l * lambda_I / n^2 * (L %*% K), epsilon = eig_tol_I)
LK = diag(n_l * lambda, n) + n_l * lambda_I / n^2 * (L %*% K)
# max_LK = max(abs(LK))
# inv_LK = solve(LK + diag(max_LK * epsilon_I, n), t(J))
inv_LK = solve(LK + diag(max(abs(LK)) * epsilon_I, n), tol = eig_tol_I)
# inv_LK = chol2inv(chol(LK + diag(max_LK * epsilon_I, n)))
# inv_LK = solve(LK / max_LK + diag(epsilon_I, n), t(J) / max_LK)
# inv_LK = chol2inv(chol(LK + diag(max_LK * epsilon_I, n)))
# inv_LK = inverse(LK, epsilon = eig_tol_I)
# Q = J %*% K %*% inv_LK
Q = J %*% K %*% inv_LK %*% t(J)
# Q = fixit(Q, epsilon = eig_tol_D)
# Q = fixit(Q, epsilon = eig_tol_D)
# Q = J %*% t(inv_LK) %*% K %*% t(J)
# Compute Q = K x inv_LK
D = matrix(0, qp_dim, qp_dim)
Amat = matrix(0, (2 * qp_dim + n_class), qp_dim)
for (j in 1:n_class) {
D = D + t(Hmatj[[j]]) %*% Q %*% Hmatj[[j]]
Amat[j, ] = rep(1, n_l) %*% Hmatj[[j]]
}
D = fixit(D, epsilon = eig_tol_D)
max_D = max(abs(D))
# D = D / max_D
diag(D) = diag(D) + max_D * epsilon_D
# diag(D) = diag(D) + epsilon_D
g_temp = matrix(-1, n_l, n_class)
g_temp[y_index] = -n_class + 1
g = as.vector(g_temp)
dvec = -g
# dvec = -g / max_D
diag(Amat[(n_class + 1):(n_class + qp_dim), ]) = 1
diag(Amat[(n_class + qp_dim + 1):(n_class + 2 * qp_dim), ]) = -1
# (3) compute Ama
# (4) compute bvec
# bvec = rep(0, (2 * qp_dim + n_class))
bvec_temp = matrix(gamma - 1, nrow = n_l, ncol = n_class)
bvec_temp[y_index] = -gamma
if (gamma == 0 | gamma == 1) {
bvec_temp = bvec_temp - epsilon
}
bvec = c(rep(0, qp_dim + n_class), as.vector(bvec_temp))
# for (j in 1:n_class) {
# for (i in 1:n_l) {
# flag = 0
# if (y[i] == j) {
# flag = 1
# }
# bvec[n_class + qp_dim + (j - 1) * n_l + i] = -(gamma * flag + (1 - gamma) * (1 - flag))
# # correction to avoid redundant constraints when gamma = 0 or 1
# if ((flag == 1 & gamma == 0) | (flag == 0 & gamma == 1)) {
# bvec[n_class + qp_dim + (j - 1) * n_l + i] = bvec[n_class + qp_dim + (j - 1) * n_l + i] - epsilon_D
# }
# }
# }
# remove one redudant constraint
Amat = Amat[c(1:(n_class - 1), (n_class + 1):(2 * qp_dim + n_class)), ]
bvec = bvec[c(1:(n_class - 1), (n_class + 1):(2 * qp_dim + n_class))]
# (5) find solution by solve.QP
nonzero = find_nonzero(t(Amat))
Amat = nonzero$Amat_compact
Aind = nonzero$Aind
dual = solve.QP.compact(D, dvec, Amat, Aind, bvec, meq = (n_class - 1))
# dual_temp = solve.QP(D, dvec, t(Amat1), bvec1, meq = (n_class - 1))
alpha = dual$solution
alpha[alpha < 0] = 0
alpha_mat = matrix(alpha, nrow = n_l, ncol = n_class)
# alpha_mat[y_index][alpha_mat[y_index] > gamma] = gamma
# for (j in 1:n_class) {
# alpha_mat[y != j, j][alpha_mat[y != j, j] > (1 - gamma)] = (1 - gamma)
# }
#
# alpha = as.vector(alpha_mat)
# for (j in 1:n_class) {
# for (i in 1:n_l) {
# if (y[i] == j & (alpha[(j - 1) * n_l + i] > gamma)) {
# alpha[(j - 1) * n_l + i] = gamma
# }
# if (y[i] != j & (alpha[(j - 1) * n_l + i] > (1 - gamma))) {
# alpha[(j - 1) * n_l + i] = (1 - gamma)
# }
# }
# }
cmat = matrix(0, n, n_class)
for (k in 1:n_class) {
cmat[, k] = inv_LK %*% t(J) %*% Hmatj[[k]] %*% alpha
}
# find b vector using LP
Kcmat = J %*% K %*% cmat
alp_temp = matrix(1 - gamma, nrow = n_l, ncol = n_class)
alp_temp[y_index] = gamma
alp = c(as.vector(alp_temp), rep(0, 2 * n_class))
# alp = rep((1 - gamma), (qp_dim + 2 * n_class))
# for (j in 1:n_class) {
# for (i in 1:n_l) {
# if (y[i] == j) {
# alp[n_l * (j - 1) + i] = gamma
# }
# }
# }
# alp[(qp_dim + 1):(qp_dim + 2 * n_class)] = 0
# constraint matrix and vector
Alp1 = c(rep(0, qp_dim), rep(c(1, -1), n_class))
Alp2 = diag(qp_dim)
Alp3 = matrix(0, nrow = qp_dim, ncol = 2 * n_class)
Alp3_temp = matrix(-1, nrow = n_l, ncol = n_class)
Alp3_temp[y_index] = 1
for (i in 1:n_class) {
Alp3[(n_l * (i - 1) + 1):(n_l * i), (2 * i - 1)] = Alp3_temp[, i]
Alp3[(n_l * (i - 1) + 1):(n_l * i), (2 * i)] = -Alp3_temp[, i]
}
Alp = rbind(Alp1, cbind(Alp2, Alp3))
blp_temp = Kcmat + 1
blp_temp[y_index] = (k - 1) - Kcmat[y_index]
blp = c(0, as.vector(blp_temp))
# constraint directions
const_dir = rep(">=", (qp_dim + 1))
const_dir[1] = "="
cposneg = lp("min", objective.in = alp, const.mat = Alp, const.dir = const_dir,const.rhs = blp)$solution[(qp_dim + 1):(qp_dim + 2 * n_class)]
c0vec = rep(0, n_class)
for(j in 1:n_class) {
c0vec[j] = cposneg[(2 * j - 1)] - cposneg[(2 * j)]
}
# compute the fitted values
fit = (matrix(rep(c0vec, n_l), ncol = n_class, byrow = T) + Kcmat)
fit_class = levs[apply(fit, 1, which.max)]
if (attr(levs, "type") == "factor") {fit_class = factor(fit_class, levels = levs)}
if (attr(levs, "type") == "numeric") {fit_class = as.numeric(fit_class)}
if (attr(levs, "type") == "integer") {fit_class = as.integer(fit_class)}
# Return the output
out$alpha = alpha_mat
out$cmat = cmat
out$c0vec = c0vec
out$fit = fit
out$fit_class = fit_class
out$n_l = n_l
out$n_u = n_u
out$n_class = n_class
out$levels = levs
return(out)
}
predict.rmlapsvm_compact = function(object, newK = NULL)
{
cmat = object$cmat
c0vec = object$c0vec
levs = object$levels
pred_y = (matrix(rep(c0vec, nrow(newK)), ncol = object$n_class, byrow = T) + (newK %*% cmat))
pred_class = levs[apply(pred_y, 1, which.max)]
if (attr(levs, "type") == "factor") {pred_class = factor(pred_class, levels = levs)}
if (attr(levs, "type") == "numeric") {pred_class = as.numeric(pred_class)}
if (attr(levs, "type") == "integer") {pred_class = as.integer(pred_class)}
return(list(class = pred_class, pred_value = pred_y))
}
rmlapsvm = function(x = NULL, y = NULL, ux = NULL, gamma = 0.5, lambda, lambda_I, kernel, kparam, scale = FALSE,
adjacency_k = 6, normalized = TRUE, weight = NULL, weightType = "Binary", epsilon = 1e-6,
eig_tol_D = 0, eig_tol_I = .Machine$double.eps, epsilon_D = 1e-8, epsilon_I = 0)
{
out = list()
n_l = NROW(x)
n_u = NROW(ux)
n = n_l + n_u
rx = rbind(x, ux)
p = ncol(x)
center = rep(0, p)
scaled = rep(1, p)
if (scale) {
rx = scale(rx)
center = attr(rx, "scaled:center")
scaled = attr(rx, "scaled:scale")
x = (x - matrix(center, nrow = n_l, ncol = p, byrow = TRUE)) / matrix(scaled, nrow = n_l, ncol = p, byrow = TRUE)
ux = (ux - matrix(center, nrow = n_u, ncol = p, byrow = TRUE)) / matrix(scaled, nrow = n_u, ncol = p, byrow = TRUE)
}
K = kernelMatrix(rx, rx, kernel = kernel, kparam = kparam)
# W = adjacency_knn(rx, distance = "euclidean", k = adjacency_k)
# graph = W
graph = make_knn_graph_mat(rx, k = adjacency_k)
L = make_L_mat(rx, kernel = kernel, kparam = kparam, graph = graph, weightType = weightType, normalized = normalized)
solutions = rmlapsvm_compact(K = K, L = L, y = y, gamma = gamma, lambda = lambda, lambda_I = lambda_I, epsilon = epsilon,
eig_tol_D = eig_tol_D, eig_tol_I = eig_tol_I, epsilon_D = epsilon_D, epsilon_I = epsilon_I)
out$x = x
out$ux = ux
out$y = y
out$n_class = solutions$n_class
out$levels = solutions$levels
out$weight = weight
out$lambda = lambda
out$lambda_I = lambda_I
out$kparam = kparam
out$cmat = solutions$cmat
out$c0vec = solutions$c0vec
out$alpha = solutions$alpha
out$epsilon = epsilon
out$eig_tol_D = eig_tol_D
out$eig_tol_I = eig_tol_I
out$epsilon_D = epsilon_D
out$epsilon_I = epsilon_I
out$kernel = kernel
out$scale = scale
out$center = center
out$scaled = scaled
out$fit_class = solutions$fit_class
class(out) = "rmlapsvm"
return(out)
}
predict.rmlapsvm = function(object, newx = NULL, newK = NULL)
{
if (object$scale) {
newx = (newx - matrix(object$center, nrow = nrow(newx), ncol = ncol(newx), byrow = TRUE)) / matrix(object$scaled, nrow = nrow(newx), ncol = ncol(newx), byrow = TRUE)
}
if (is.null(newK)) {
newK = kernelMatrix(newx, rbind(object$x, object$ux), kernel = object$kernel, kparam = object$kparam)
# newK = kernelMatrix(rbfdot(sigma = object$kparam), newx, object$x)
}
cmat = object$cmat
c0vec = object$c0vec
levs = object$levels
pred_y = (matrix(rep(c0vec, nrow(newK)), ncol = object$n_class, byrow = T) + (newK %*% cmat))
pred_class = levs[apply(pred_y, 1, which.max)]
if (attr(levs, "type") == "factor") {pred_class = factor(pred_class, levels = levs)}
if (attr(levs, "type") == "numeric") {pred_class = as.numeric(pred_class)}
if (attr(levs, "type") == "integer") {pred_class = as.integer(pred_class)}
return(list(class = pred_class, pred_value = pred_y))
}
cv.rmlapsvm = function(x, y, ux = NULL, gamma = 0.5, valid_x = NULL, valid_y = NULL, nfolds = 5,
lambda_seq = 2^{seq(-10, 15, length.out = 100)}, lambda_I_seq = 2^{seq(-20, 15, length.out = 20)},
kernel = c("linear", "gaussian", "poly", "spline", "anova_gaussian"), kparam = c(1),
scale = FALSE, adjacency_k = 6, weightType = "Heatmap", normalized = TRUE,
criterion = c("0-1", "loss"), optModel = FALSE, nCores = 1, ...)
{
out = list()
call = match.call()
kernel = match.arg(kernel)
criterion = match.arg(criterion)
# if (scale) {
# x = scale(x)
# if (!is.null(valid_x)) {
# means = attr(x, "scaled:center")
# stds = attr(x, "scaled:scale")
# valid_x = (valid_x - matrix(means, NROW(x), NCOL(x), byrow = TRUE)) / matrix(stds, NROW(x), NCOL(x), byrow = TRUE)
# }
# }
lambda_seq = as.numeric(lambda_seq)
lambda_I_seq = as.numeric(lambda_I_seq)
kparam = as.numeric(kparam)
lambda_seq = sort(lambda_seq, decreasing = FALSE)
lambda_I_seq = sort(lambda_I_seq, decreasing = FALSE)
# kparam = sort(kparam, decreasing = TRUE)
# Combination of hyper-parameters
# params = expand.grid(lambda = lambda_seq, lambda_I = lambda_I_seq[order(lambda_I_seq, decreasing = TRUE)], kparam = kparam)
# params = expand.grid(lambda = lambda_seq, lambda_I = lambda_I_seq, kparam = kparam)
params = expand.grid(lambda = lambda_seq, lambda_I = lambda_I_seq)
if (!is.null(valid_x) & !is.null(valid_y)) {
model_list = vector("list", 1)
fold_list = NULL
# Parallel computation on the combination of hyper-parameters
fold_err = mclapply(1:nrow(params),
function(j) {
error = try({
rmsvm_fit = rmlapsvm(x = x, y = y, ux = ux, gamma = gamma,
lambda = params$lambda[j], lambda_I = params$lambda_I[j],
kernel = kernel, kparam = kparam, scale = scale,
adjacency_k = adjacency_k, weightType = weightType,
normalized = normalized, ...)
})
if (!inherits(error, "try-error")){
pred_val = predict.rmlapsvm(rmsvm_fit, newx = valid_x)
if (criterion == "0-1") {
acc = sum(valid_y == pred_val$class) / length(valid_y)
err = 1 - acc
} else {
# err = ramsvm_hinge(valid_y, pred_val$inner_prod, k = k, gamma = gamma)
}
} else {
rmsvm_fit = NULL
err = Inf
}
return(list(error = err, fit_model = rmsvm_fit))
}, mc.cores = nCores)
valid_err = sapply(fold_err, "[[", "error")
model_list[[1]] = lapply(fold_err, "[[", "fit_model")
opt_ind = max(which(valid_err == min(valid_err)))
opt_param = params[opt_ind, ]
opt_valid_err = min(valid_err)
} else {
fold_list_l = data_split(y, nfolds = nfolds)
if (!is.null(ux)) {
fold_list_ul = sample(rep_len(1:nfolds, length.out = nrow(ux)))
} else {
fold_list_ul = NULL
}
valid_err_mat = matrix(NA, nrow = nfolds, ncol = nrow(params), dimnames = list(paste0("Fold", 1:nfolds)))
for (i in 1:nfolds) {
cat(nfolds, "- fold CV :", i / nfolds * 100, "%", "\r")
fold_l = which(fold_list_l == i)
# fold_ul = which(fold_list_ul == i)
fold_ul = NULL
y_fold = y[-fold_l]
x_fold = x[-fold_l, , drop = FALSE]
y_valid = y[fold_l]
x_valid = x[fold_l, , drop = FALSE]
# ux_fold = ux[-fold_ul, , drop = FALSE]
ux_fold = ux
fold_err = mclapply(1:nrow(params),
function(j) {
error = try({
msvm_fit = rmlapsvm(x = x_fold, y = y_fold, ux = ux_fold, gamma = gamma,
lambda = params$lambda[j], lambda_I = params$lambda_I[j],
kernel = kernel, kparam = kparam, scale = scale,
adjacency_k = adjacency_k, weightType = weightType,
normalized = normalized, ...)
})
if (!inherits(error, "try-error")) {
pred_val = predict.rmlapsvm(msvm_fit, newx = x_valid)
if (criterion == "0-1") {
acc = sum(y_valid == pred_val$class) / length(y_valid)
err = 1 - acc
} else {
# err = ramsvm_hinge(y_valid, pred_val$inner_prod, k = k, gamma = gamma)
}
} else {
msvm_fit = NULL
err = Inf
}
return(list(error = err, fit_model = msvm_fit))
}, mc.cores = nCores)
valid_err_mat[i, ] = sapply(fold_err, "[[", "error")
# model_list[[i]] = lapply(fold_err, "[[", "fit_model")
}
valid_err = colMeans(valid_err_mat)
opt_ind = max(which(valid_err == min(valid_err)))
opt_param = params[opt_ind, ]
# opt_param = c(lambda = opt_param$lambda, lambda_I = opt_param$lambda_I)
opt_valid_err = min(valid_err)
}
out$opt_param = c(lambda = opt_param$lambda, lambda_I = opt_param$lambda_I)
out$opt_valid_err = opt_valid_err
out$opt_ind = opt_ind
out$valid_err = valid_err
out$x = x
out$y = y
out$valid_x = valid_x
out$valid_y = valid_y
out$kernel = kernel
out$kparam = kparam
out$gamma = gamma
out$scale = scale
if (optModel) {
opt_model = rmlapsvm(x = x, y = y, ux = ux, gamma = gamma,
lambda = opt_param$lambda, lambda_I = opt_param$lambda_I,
kernel = kernel, kparam = kparam, scale = scale,
adjacency_k = adjacency_k, weightType = weightType, normalized = normalized, ...)
out$opt_model = opt_model
}
out$call = call
class(out) = "rmlapsvm"
return(out)
}
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