/* Dirichlet posterior probabilities (covers BDe and K2 scores). */
double dirichlet_node(SEXP target, SEXP x, SEXP data, SEXP iss, SEXP prior,
SEXP beta, SEXP experimental, int sparse, int debuglevel) {
char *t = (char *)CHAR(STRING_ELT(target, 0));
double prob = 0, prior_prob = 0;
SEXP nodes, node_t, data_t, exp_data, parents, parent_vars, config;
/* get the node cached information. */
nodes = getListElement(x, "nodes");
node_t = getListElement(nodes, t);
/* get the parents of the node. */
parents = getListElement(node_t, "parents");
/* extract the node's column from the data frame. */
data_t = c_dataframe_column(data, target, TRUE, FALSE);
/* extract the list of eperimental data. */
exp_data = c_dataframe_column(experimental, target, TRUE, FALSE);
/* compute the prior probability component for the node. */
prior_prob = graph_prior_prob(prior, target, node_t, beta, debuglevel);
if (length(parents) == 0) {
prob = dpost(data_t, iss, exp_data);
}/*THEN*/
else {
/* generate the configurations of the parents. */
PROTECT(parent_vars = c_dataframe_column(data, parents, FALSE, FALSE));
PROTECT(config = c_configurations(parent_vars, TRUE, !sparse));
/* compute the marginal likelihood. */
prob = cdpost(data_t, config, iss, exp_data);
UNPROTECT(2);
}/*ELSE*/
if (debuglevel > 0) {
Rprintf(" > (log)prior probability is %lf.\n", prior_prob);
Rprintf(" > (log)posterior density is %lf.\n", prob);
}/*THEN*/
/* add the (log)prior to the marginal (log)likelihood to get the (log)posterior. */
prob += prior_prob;
return prob;
}/*DIRICHLET_NODE*/
/* multinomial loss for a single node. */
double c_dloss(int *cur, SEXP cur_parents, int *configs, double *prob,
SEXP data, SEXP nodes, int ndata, int nlevels, double *per_sample) {
int i = 0, dropped = 0, *obs = NULL;
double logprob = 0, result = 0;
SEXP temp_df;
/* get the target variable. */
obs = INTEGER(VECTOR_ELT(data, *cur));
/* get the parents' configurations. */
if (LENGTH(cur_parents) > 0) {
PROTECT(temp_df = c_dataframe_column(data, cur_parents, FALSE, FALSE));
cfg(temp_df, configs, NULL);
for (i = 0; i < ndata; i++) {
logprob = log(prob[CMC(obs[i] - 1, configs[i], nlevels)]);
if (!R_FINITE(logprob) || ISNAN(logprob))
dropped++;
else
result += logprob;
if (per_sample)
per_sample[i] += logprob;
}/*FOR*/
UNPROTECT(1);
}/*THEN*/
else {
for (i = 0; i < ndata; i++) {
logprob = log(prob[obs[i] - 1]);
if (!R_FINITE(logprob) || ISNAN(logprob))
dropped++;
else
result += logprob;
if (per_sample)
per_sample[i] += logprob;
}/*FOR*/
}/*ELSE*/
/* switch to the negentropy. */
result /= -(ndata - dropped);
/* print a warning if data were dropped. */
if (dropped > 0)
warning("%d observations were dropped because the corresponding probabilities for node %s were 0 or NaN.", dropped, NODE(*cur));
return result;
}/*C_DLOSS*/
double loglik_dnode(SEXP target, SEXP x, SEXP data, double *nparams, int debuglevel) {
double loglik = 0;
char *t = (char *)CHAR(STRING_ELT(target, 0));
SEXP nodes, node_t, parents, data_t, parent_vars, config;
/* get the node cached information. */
nodes = getListElement(x, "nodes");
node_t = getListElement(nodes, t);
/* get the parents of the node. */
parents = getListElement(node_t, "parents");
/* extract the node's column from the data frame. */
PROTECT(data_t = c_dataframe_column(data, target, TRUE, FALSE));
if (length(parents) == 0) {
loglik = dlik(data_t, nparams);
}/*THEN*/
else {
/* generate the configurations of the parents. */
PROTECT(parent_vars = c_dataframe_column(data, parents, FALSE, FALSE));
PROTECT(config = c_configurations(parent_vars, TRUE, TRUE));
/* compute the log-likelihood. */
loglik = cdlik(data_t, config, nparams);
UNPROTECT(2);
}/*ELSE*/
if (debuglevel > 0)
Rprintf(" > loglikelihood is %lf.\n", loglik);
UNPROTECT(1);
return loglik;
}/*LOGLIK_DNODE*/
/* unconditional independence tests. */
SEXP utest(SEXP x, SEXP y, SEXP data, SEXP test, SEXP B, SEXP alpha,
SEXP learning) {
int ntests = length(x), nobs = 0;
double *pvalue = NULL, statistic = 0, df = NA_REAL;
const char *t = CHAR(STRING_ELT(test, 0));
test_e test_type = test_label(t);
SEXP xx, yy, result;
/* allocate the return value, which has the same length as x. */
PROTECT(result = allocVector(REALSXP, ntests));
setAttrib(result, R_NamesSymbol, x);
pvalue = REAL(result);
/* set all elements to zero. */
memset(pvalue, '\0', ntests * sizeof(double));
/* extract the variables from the data. */
PROTECT(xx = c_dataframe_column(data, x, FALSE, FALSE));
PROTECT(yy = c_dataframe_column(data, y, TRUE, FALSE));
nobs = length(yy);
if (IS_DISCRETE_ASYMPTOTIC_TEST(test_type)) {
/* parametric tests for discrete variables. */
statistic = ut_discrete(xx, yy, nobs, ntests, pvalue, &df, test_type);
}/*THEN*/
else if ((test_type == COR) || (test_type == ZF) || (test_type == MI_G) ||
(test_type == MI_G_SH)) {
/* parametric tests for Gaussian variables. */
statistic = ut_gaustests(xx, yy, nobs, ntests, pvalue, &df, test_type);
}/*THEN*/
else if (test_type == MI_CG) {
/* conditional linear Gaussian mutual information test. */
statistic = ut_micg(xx, yy, nobs, ntests, pvalue, &df);
}/*THEN*/
else if (IS_DISCRETE_PERMUTATION_TEST(test_type)) {
statistic = ut_dperm(xx, yy, nobs, ntests, pvalue, &df, test_type, INT(B),
IS_SMC(test_type) ? NUM(alpha) : 1);
}/*THEN*/
else if (IS_CONTINUOUS_PERMUTATION_TEST(test_type)) {
statistic = ut_gperm(xx, yy, nobs, ntests, pvalue, test_type, INT(B),
IS_SMC(test_type) ? NUM(alpha) : 1);
}/*THEN*/
UNPROTECT(3);
/* catch-all for unknown tests (after deallocating memory.) */
if (test_type == ENOTEST)
error("unknown test statistic '%s'.", t);
/* increase the test counter. */
test_counter += ntests;
if (isTRUE(learning))
return result;
else
return c_create_htest(statistic, test, pvalue[ntests - 1], df, B);
}/*UTEST*/
SEXP entropy_loss(SEXP fitted, SEXP orig_data, SEXP by_sample, SEXP keep,
SEXP debug) {
int i = 0, k = 0, ndata = 0, nnodes = LENGTH(fitted), nlevels = 0, type = 0;
int *configs = NULL, *debuglevel = LOGICAL(debug), *by = LOGICAL(by_sample);
int *to_keep = NULL;
double *res = 0, *res_sample = NULL, **columns = 0, cur_loss = 0;
const char *class = NULL;
SEXP data, cur_node, nodes, result, result_sample, coefs, sd, parents, try;
/* get the node labels. */
nodes = getAttrib(fitted, R_NamesSymbol);
/* rearrange the columns of the data to match the network. */
PROTECT(data = c_dataframe_column(orig_data, nodes, FALSE, TRUE));
/* get the sample size. */
ndata = LENGTH(VECTOR_ELT(data, 0));
/* allocate and initialize the return value. */
PROTECT(result = allocVector(REALSXP, 1));
res = REAL(result);
*res = 0;
/* allocate the sample's contributions if needed. */
if (*by > 0) {
PROTECT(result_sample = allocVector(REALSXP, ndata));
res_sample = REAL(result_sample);
memset(res_sample, '\0', ndata * sizeof(double));
}/*THEN*/
/* find out which nodes to use in computing the entropy loss. */
PROTECT(try = match(nodes, keep, 0));
to_keep = INTEGER(try);
R_isort(to_keep, LENGTH(try));
/* determine the class of the fitted network. */
class = CHAR(STRING_ELT(getAttrib(VECTOR_ELT(fitted, 0), R_ClassSymbol), 0));
if (strcmp(class, "bn.fit.gnode") == 0) {
/* dereference the data set's columns. */
columns = (double **) alloc1dpointer(nnodes);
for (i = 0; i < nnodes; i++)
columns[i] = REAL(VECTOR_ELT(data, i));
type = GAUSSIAN;
}/*THEN*/
else if ((strcmp(class, "bn.fit.dnode") == 0) || (strcmp(class, "bn.fit.onode") == 0)) {
/* allocate an array for parents' configurations. */
configs = alloc1dcont(ndata);
type = DISCRETE;
}/*THEN*/
/* iterate over the nodes. */
for (i = 0; i < nnodes; i++) {
if (i == to_keep[k] - 1) {
k++;
}/*THEN*/
else {
if (*debuglevel > 0)
Rprintf(" > skipping node %s.\n", NODE(i));
continue;
}/*ELSE*/
/* get the current node. */
cur_node = VECTOR_ELT(fitted, i);
/* get the parents of the node. */
parents = getListElement(cur_node, "parents");
/* get the parameters (regression coefficients and residuals' standard
* deviation for Gaussian nodes, conditional probabilities for discrete
* nodes), and compute the loss. */
switch(type) {
case GAUSSIAN:
coefs = getListElement(cur_node, "coefficients");
sd = getListElement(cur_node, "sd");
cur_loss = c_gloss(&i, parents, REAL(coefs), REAL(sd), columns, nodes,
ndata, res_sample);
break;
case DISCRETE:
coefs = getListElement(cur_node, "prob");
nlevels = INT(getAttrib(coefs, R_DimSymbol));
cur_loss = c_dloss(&i, parents, configs, REAL(coefs), data, nodes,
ndata, nlevels, res_sample);
break;
}/*SWITCH*/
if (*debuglevel > 0)
Rprintf(" > log-likelihood loss for node %s is %lf.\n", NODE(i), cur_loss);
/* add the node contribution to the return value. */
*res += cur_loss;
}/*FOR*/
if (*by > 0) {
UNPROTECT(4);
return result_sample;
}/*THEN*/
else {
UNPROTECT(3);
return result;
}/*ELSE*/
}/*ENTROPY_LOSS*/
