/* unconditional mutual information, to be used in C code. */
double c_mi(int *xx, int *llx, int *yy, int *lly, int *num) {
int i = 0, j = 0, k = 0;
int **n = NULL, *ni = NULL, *nj = NULL;
double res = 0;
/* initialize the contingency table and the marginal frequencies. */
n = alloc2dcont(*llx, *lly);
ni = alloc1dcont(*llx);
nj = alloc1dcont(*lly);
/* compute the joint frequency of x and y. */
for (k = 0; k < *num; k++) {
n[xx[k] - 1][yy[k] - 1]++;
}/*FOR*/
/* compute the marginals. */
for (i = 0; i < *llx; i++)
for (j = 0; j < *lly; j++) {
ni[i] += n[i][j];
nj[j] += n[i][j];
}/*FOR*/
/* compute the mutual information from the joint and marginal frequencies. */
for (i = 0; i < *llx; i++)
for (j = 0; j < *lly; j++)
res += MI_PART(n[i][j], ni[i], nj[j], *num);
return (res)/(*num);
}/*C_MI*/
/* compute the mutual information from the joint and marginal frequencies. */
static double _mi(int *n, int *nrowt, int *ncolt, int *nrows,
int *ncols, int *length) {
int i = 0, j = 0;
double res = 0;
for (i = 0; i < *nrows; i++)
for (j = 0; j < *ncols; j++)
res += MI_PART(n[CMC(i, j, *nrows)], nrowt[i], ncolt[j], *length);
return res;
}/*_MI*/
/* compute the mutual information from the joint and marginal frequencies. */
double mi_kernel(int **n, int *nrowt, int *ncolt, int nrows, int ncols,
int length) {
int i = 0, j = 0;
double res = 0;
for (i = 0; i < nrows; i++)
for (j = 0; j < ncols; j++)
res += MI_PART(n[i][j], nrowt[i], ncolt[j], length);
return res;
}/*MI_KERNEL*/
/* compute the conditional mutual information from the joint and marginal frequencies. */
static double _cmi(int **n, int **nrowt, int **ncolt, int *ncond,
int *nr, int *nc, int *nl) {
int i = 0, j = 0, k = 0;
double res = 0;
for (k = 0; k < *nl; k++)
for (j = 0; j < *nc; j++)
for (i = 0; i < *nr; i++)
res += MI_PART(n[k][CMC(i, j, *nr)], nrowt[k][i], ncolt[k][j], ncond[k]);
return res;
}/*_CMI*/
/* compute the conditional mutual information from the joint and marginal
* frequencies. */
double cmi_kernel(int ***n, int **nrowt, int **ncolt, int *ncond, int nr,
int nc, int nl) {
int i = 0, j = 0, k = 0;
double res = 0;
for (k = 0; k < nl; k++)
for (j = 0; j < nc; j++)
for (i = 0; i < nr; i++)
res += MI_PART(n[k][i][j], nrowt[k][i], ncolt[k][j], ncond[k]);
return res;
}/*CMI_KERNEL*/
/* conditional mutual information, to be used in C code. */
double c_cmi(int *xx, int *llx, int *yy, int *lly, int *zz, int *llz, int *num) {
int i = 0, j = 0, k = 0;
int ***n = NULL, **ni = NULL, **nj = NULL, *nk = NULL;
double res = 0;
/* initialize the contingency table and the marginal frequencies. */
n = alloc3dcont(*llx, *lly, *llz);
ni = alloc2dcont(*llx, *llz);
nj = alloc2dcont(*lly, *llz);
nk = alloc1dcont(*llz);
/* compute the joint frequency of x, y, and z. */
for (k = 0; k < *num; k++) {
n[xx[k] - 1][yy[k] - 1][zz[k] - 1]++;
}/*FOR*/
/* compute the marginals. */
for (i = 0; i < *llx; i++)
for (j = 0; j < *lly; j++)
for (k = 0; k < *llz; k++) {
ni[i][k] += n[i][j][k];
nj[j][k] += n[i][j][k];
nk[k] += n[i][j][k];
}/*FOR*/
/* compute the conditional mutual information from the joint and
marginal frequencies. */
for (i = 0; i < *llx; i++)
for (j = 0; j < *lly; j++)
for (k = 0; k < *llz; k++)
res += MI_PART(n[i][j][k], ni[i][k], nj[j][k], nk[k]);
res = res/(*num);
return res;
}/*C_CMI*/
