// modificato il prototipo per aumentare l'efficienza
VETTOREi *sample1(VETTOREi *ris, int n, int k, int replace, double *p)
{
int *x;
int i, nc = 0;
GetRNGstate();
CREAv_i(ris, k);
// g_x mi serve comunque (e sempre di dim. n)
// OTTIMIZZATA da me!
CREAv_i(g_x, n); // cosi` non ho problemi nel caso sia troppo piccolo
x = g_x->dati;
if (p != NULL) {
FixupProb(p, n, k, replace);
if (replace) {
for (i = 0; i < n; i++) {
if (n * p[i] > 0.1)
nc++;
}
if (nc > 200)
walker_ProbSampleReplace(n, p, x, k, ris->dati);
else
ProbSampleReplace(n, p, x, k, ris->dati);
}
else
ProbSampleNoReplace(n, p, x, k, ris->dati);
}
else {
/* avoid allocation for a single sample */
if (replace || k < 2)
SampleReplace(k, n, ris->dati);
else { // ho gia` allocato g_x
SampleNoReplace(k, n, ris->dati, x);
}
}
PutRNGstate();
return ris;
}
/* predict the value of a discrete node without parents. */
SEXP dpred(SEXP fitted, SEXP data, SEXP debug) {
int i = 0, nmax = 0, ndata = LENGTH(data), length = 0;
int *res = NULL, *debuglevel = LOGICAL(debug), *iscratch = NULL, *maxima = NULL;
double *prob = NULL, *dscratch = NULL, *buf = NULL;
SEXP ptab, result, tr_levels = getAttrib(data, R_LevelsSymbol);
/* get the probabilities of the multinomial distribution. */
ptab = getListElement(fitted, "prob");
length = LENGTH(ptab);
prob = REAL(ptab);
/* create the vector of indexes. */
iscratch = alloc1dcont(length);
for (i = 0; i < length; i++)
iscratch[i] = i + 1;
/* create a scratch copy of the array. */
buf = alloc1dreal(length);
dscratch = alloc1dreal(length);
memcpy(dscratch, prob, length * sizeof(double));
/* allocate the array for the indexes of the maxima. */
maxima = alloc1dcont(length);
/* find out the mode(s). */
all_max(dscratch, length, maxima, &nmax, iscratch, buf);
/* allocate and initialize the return value. */
PROTECT(result = allocVector(INTSXP, ndata));
res = INTEGER(result);
if (nmax == 1) {
/* copy the index of the mode in the return value. */
for (i = 0; i < ndata; i++)
res[i] = maxima[0];
if (*debuglevel > 0) {
if (res[0] == NA_INTEGER)
Rprintf(" > prediction for all observations is NA with probabilities:\n");
else
Rprintf(" > prediction for all observations is '%s' with probabilities:\n",
CHAR(STRING_ELT(tr_levels, res[0] - 1)));
Rprintf(" ");
for (i = 0; i < LENGTH(ptab); i++)
Rprintf(" %lf", prob[i]);
Rprintf("\n");
}/*THEN*/
}/*THEN*/
else {
/* break ties: sample with replacement from all the maxima. */
GetRNGstate();
SampleReplace(ndata, nmax, res, maxima);
PutRNGstate();
if (*debuglevel > 0) {
Rprintf(" > there are %d levels tied for prediction, applying tie breaking.\n", nmax);
Rprintf(" > tied levels are:");
for (i = 0; i < nmax; i++)
Rprintf(" %s", CHAR(STRING_ELT(tr_levels, maxima[i] - 1)));
Rprintf(".\n");
}/*THEN*/
}/*ELSE*/
/* copy the labels and the class from the input data. */
setAttrib(result, R_LevelsSymbol, tr_levels);
setAttrib(result, R_ClassSymbol, getAttrib(data, R_ClassSymbol));
UNPROTECT(1);
return result;
}/*DPRED*/
/* predict the value of the training variable in a naive Bayes or Tree-Augmented
* naive Bayes classifier. */
SEXP naivepred(SEXP fitted, SEXP data, SEXP parents, SEXP training, SEXP prior,
SEXP prob, SEXP debug) {
int i = 0, j = 0, k = 0, n = 0, nvars = LENGTH(fitted), nmax = 0, tr_nlevels = 0;
int *res = NULL, **ex = NULL, *ex_nlevels = NULL;
int idx = 0, *tr_id = INTEGER(training);
int *iscratch = NULL, *maxima = NULL, *prn = NULL, *debuglevel = LOGICAL(debug);
int *include_prob = LOGICAL(prob);
double **cpt = NULL, *pr = NULL, *scratch = NULL, *buf = NULL, *pt = NULL;
double sum = 0;
SEXP class, temp, tr, tr_levels, result, nodes, probtab, dimnames;
/* cache the node labels. */
nodes = getAttrib(fitted, R_NamesSymbol);
/* cache the pointers to all the variables. */
ex = (int **) alloc1dpointer(nvars);
ex_nlevels = alloc1dcont(nvars);
for (i = 0; i < nvars; i++) {
temp = VECTOR_ELT(data, i);
ex[i] = INTEGER(temp);
ex_nlevels[i] = NLEVELS(temp);
}/*FOR*/
/* get the training variable and its levels. */
n = LENGTH(VECTOR_ELT(data, 0));
tr = getListElement(VECTOR_ELT(fitted, *tr_id - 1), "prob");
tr_levels = VECTOR_ELT(getAttrib(tr, R_DimNamesSymbol), 0);
tr_nlevels = LENGTH(tr_levels);
/* get the prior distribution. */
pr = REAL(prior);
if (*debuglevel > 0) {
Rprintf("* the prior distribution for the target variable is:\n");
PrintValue(prior);
}/*THEN*/
/* allocate the scratch space used to compute posterior probabilities. */
scratch = alloc1dreal(tr_nlevels);
buf = alloc1dreal(tr_nlevels);
/* cache the pointers to the conditional probability tables. */
cpt = (double **) alloc1dpointer(nvars);
for (i = 0; i < nvars; i++)
cpt[i] = REAL(getListElement(VECTOR_ELT(fitted, i), "prob"));
/* dereference the parents' vector. */
prn = INTEGER(parents);
/* create the vector of indexes. */
iscratch = alloc1dcont(tr_nlevels);
/* allocate the array for the indexes of the maxima. */
maxima = alloc1dcont(tr_nlevels);
/* allocate the return value. */
PROTECT(result = allocVector(INTSXP, n));
res = INTEGER(result);
/* allocate and initialize the table of the posterior probabilities. */
if (*include_prob > 0) {
PROTECT(probtab = allocMatrix(REALSXP, tr_nlevels, n));
pt = REAL(probtab);
memset(pt, '\0', n * tr_nlevels * sizeof(double));
}/*THEN*/
/* initialize the random seed, just in case we need it for tie breaking. */
GetRNGstate();
/* for each observation... */
for (i = 0; i < n; i++) {
/* ... reset the scratch space and the indexes array... */
for (k = 0; k < tr_nlevels; k++) {
scratch[k] = log(pr[k]);
iscratch[k] = k + 1;
}/*FOR*/
if (*debuglevel > 0)
Rprintf("* predicting the value of observation %d.\n", i + 1);
/* ... and for each conditional probability table... */
for (j = 0; j < nvars; j++) {
/* ... skip the training variable... */
if (*tr_id == j + 1)
continue;
/* ... (this is the root node of the Chow-Liu tree) ... */
if (prn[j] == NA_INTEGER) {
/* ... and for each row of the conditional probability table... */
for (k = 0; k < tr_nlevels; k++) {
if (*debuglevel > 0) {
Rprintf(" > node %s: picking cell %d (%d, %d) from the CPT (p = %lf).\n",
NODE(j), CMC(ex[j][i] - 1, k, ex_nlevels[j]), ex[j][i], k + 1,
cpt[j][CMC(ex[j][i] - 1, k, ex_nlevels[j])]);
}/*THEN*/
/* ... update the posterior probability. */
scratch[k] += log(cpt[j][CMC(ex[j][i] - 1, k, ex_nlevels[j])]);
}/*FOR*/
}/*THEN*/
else {
/* ... and for each row of the conditional probability table... */
for (k = 0; k < tr_nlevels; k++) {
/* (the first dimension corresponds to the current node [X], the second
* to the training node [Y], the third to the only parent of the current
* node [Z]; CMC coordinates are computed as X + Y * NX + Z * NX * NY. */
idx = (ex[j][i] - 1) + k * ex_nlevels[j] +
(ex[prn[j] - 1][i] - 1) * ex_nlevels[j] * tr_nlevels;
if (*debuglevel > 0) {
Rprintf(" > node %s: picking cell %d (%d, %d, %d) from the CPT (p = %lf).\n",
NODE(j), idx, ex[j][i], k + 1, ex[prn[j] - 1][i], cpt[j][idx]);
}/*THEN*/
/* ... update the posterior probability. */
scratch[k] += log(cpt[j][idx]);
}/*FOR*/
}/*ELSE*/
}/*FOR*/
/* find out the mode(s). */
all_max(scratch, tr_nlevels, maxima, &nmax, iscratch, buf);
/* compute the posterior probabilities on the right scale, to attach them
* to the return value. */
if (*include_prob) {
/* copy the log-probabilities from scratch. */
memcpy(pt + i * tr_nlevels, scratch, tr_nlevels * sizeof(double));
/* transform log-probabilitiees into plain probabilities. */
for (k = 0, sum = 0; k < tr_nlevels; k++)
sum += pt[i * tr_nlevels + k] = exp(pt[i * tr_nlevels + k] - scratch[maxima[0] - 1]);
/* rescale them to sum up to 1. */
for (k = 0; k < tr_nlevels; k++)
pt[i * tr_nlevels + k] /= sum;
}/*THEN*/
if (nmax == 1) {
res[i] = maxima[0];
if (*debuglevel > 0) {
Rprintf(" @ prediction for observation %d is '%s' with (log-)posterior:\n",
i + 1, CHAR(STRING_ELT(tr_levels, res[i] - 1)));
Rprintf(" ");
for (k = 0; k < tr_nlevels; k++)
Rprintf(" %lf", scratch[k]);
Rprintf("\n");
}/*THEN*/
}/*THEN*/
else {
/* break ties: sample with replacement from all the maxima. */
SampleReplace(1, nmax, res + i, maxima);
if (*debuglevel > 0) {
Rprintf(" @ there are %d levels tied for prediction of observation %d, applying tie breaking.\n", nmax, i + 1);
Rprintf(" ");
for (k = 0; k < tr_nlevels; k++)
Rprintf(" %lf", scratch[k]);
Rprintf("\n");
Rprintf(" @ tied levels are:");
for (k = 0; k < nmax; k++)
Rprintf(" %s", CHAR(STRING_ELT(tr_levels, maxima[k] - 1)));
Rprintf(".\n");
}/*THEN*/
}/*ELSE*/
}/*FOR*/
/* save the state of the random number generator. */
PutRNGstate();
/* add back the attributes and the class to the return value. */
PROTECT(class = allocVector(STRSXP, 1));
SET_STRING_ELT(class, 0, mkChar("factor"));
setAttrib(result, R_LevelsSymbol, tr_levels);
setAttrib(result, R_ClassSymbol, class);
if (*include_prob > 0) {
/* set the levels of the taregt variable as rownames. */
PROTECT(dimnames = allocVector(VECSXP, 2));
SET_VECTOR_ELT(dimnames, 0, tr_levels);
setAttrib(probtab, R_DimNamesSymbol, dimnames);
/* add the posterior probabilities to the return value. */
setAttrib(result, install("prob"), probtab);
UNPROTECT(4);
}/*THEN*/
else {
UNPROTECT(2);
}/*ELSE*/
return result;
}/*NAIVEPRED*/
/* predict the value of a discrete node with one or more parents. */
SEXP cdpred(SEXP fitted, SEXP data, SEXP parents, SEXP debug) {
int i = 0, k = 0, ndata = LENGTH(data), nrows = 0, ncols = 0;
int *configs = INTEGER(parents), *debuglevel = LOGICAL(debug);
int *iscratch = NULL, *maxima = NULL, *nmax = NULL, *res = NULL;
double *prob = NULL, *dscratch = NULL, *buf = NULL;
SEXP temp, result, tr_levels = getAttrib(data, R_LevelsSymbol);
/* get the probabilities of the multinomial distribution. */
temp = getListElement(fitted, "prob");
nrows = INT(getAttrib(temp, R_DimSymbol));
ncols = LENGTH(temp) / nrows;
prob = REAL(temp);
/* create the vector of indexes. */
iscratch = alloc1dcont(nrows);
/* create a scratch copy of the array. */
buf = alloc1dreal(nrows);
dscratch = alloc1dreal(nrows * ncols);
memcpy(dscratch, prob, nrows * ncols * sizeof(double));
/* allocate the array for the indexes of the maxima. */
maxima = alloc1dcont(nrows * ncols);
/* allocate the maxima counters. */
nmax = alloc1dcont(ncols);
/* get the mode for each configuration. */
for (i = 0; i < ncols; i++) {
/* initialize the vector of indexes. */
for (k = 0; k < nrows; k++)
iscratch[k] = k + 1;
/* find out the mode(s). */
all_max(dscratch + i * nrows, nrows, maxima + i * nrows,
nmax + i, iscratch, buf);
}/*FOR*/
/* allocate and initialize the return value. */
PROTECT(result = allocVector(INTSXP, ndata));
res = INTEGER(result);
/* initialize the random seed, just in case we need it for tie breaking. */
GetRNGstate();
/* copy the index of the mode in the return value. */
for (i = 0; i < ndata; i++) {
if (nmax[configs[i] - 1] == 1) {
res[i] = maxima[CMC(0, configs[i] - 1, nrows)];
if (*debuglevel > 0) {
if (res[i] == NA_INTEGER)
Rprintf(" > prediction for observation %d is NA with probabilities:\n");
else
Rprintf(" > prediction for observation %d is '%s' with probabilities:\n",
i + 1, CHAR(STRING_ELT(tr_levels, res[i] - 1)));
Rprintf(" ");
for (int k = 0; k < nrows; k++)
Rprintf(" %lf", (prob + nrows * (configs[i] - 1))[k]);
Rprintf("\n");
}/*THEN*/
}/*THEN*/
else {
/* break ties: sample with replacement from all the maxima. */
SampleReplace(1, nmax[configs[i] - 1], res + i, maxima + (configs[i] - 1) * nrows);
if (*debuglevel > 0) {
Rprintf(" > there are %d levels tied for prediction of observation %d, applying tie breaking.\n",
nmax[configs[i] - 1], i + 1);
Rprintf(" > tied levels are:");
for (k = 0; k < nmax[configs[i] - 1]; k++)
Rprintf(" %s", CHAR(STRING_ELT(tr_levels, maxima[CMC(k, configs[i] - 1, nrows)] - 1)));
Rprintf(".\n");
}/*THEN*/
}/*ELSE*/
}/*FOR*/
/* save the state of the random number generator. */
PutRNGstate();
/* copy the labels and the class from the input data. */
setAttrib(result, R_LevelsSymbol, tr_levels);
setAttrib(result, R_ClassSymbol, getAttrib(data, R_ClassSymbol));
UNPROTECT(1);
return result;
}/*CDPRED*/
