+/* delta_plot.c 2010-01-12 */
+
+/* Copyright 2010 Emmanuel Paradis
+
+/* This file is part of the R-package `ape'. */
+/* See the file ../COPYING for licensing issues. */
+
+#include <R.h>
+
+void delta_plot(double *D, int *size, int *nbins, int *counts, double *deltabar)
+{
+ int x, y, u, v; /* same notation than in Holland et al. 2002 */
+ int n = *size, nb = *nbins;
+ double dxy, dxu, dxv, dyu, dyv, duv, A, B, C, delta;
+ int xy, xu, xv, yu, yv, uv, i, k;
+
+ for (x = 0; x < n - 3; x++) {
+ xy = x*n - x*(x + 1)/2; /* do NOT factorize */
+ for (y = x + 1; y < n - 2; y++, xy++) {
+ yu = y*n - y*(y + 1)/2; /* do NOT factorize */
+ dxy = D[xy];
+ xu = xy + 1;
+ for (u = y + 1; u < n - 1; u++, xu++, yu++) {
+ uv = u*n - u*(u + 1)/2; /* do NOT factorize */
+ dxu = D[xu];
+ dyu = D[yu];
+ xv = xu + 1;
+ yv = yu + 1;
+ for (v = u + 1; v < n; v++, xv++, yv++, uv++) {
+ dxv = D[xv];
+ dyv = D[yv];
+ duv = D[uv];
+ /* if (dxy <= dxu && dxy <= dxv && dxy <= dyu && dxy <= dyv && dxy <= duv) k=1; */
+/* else if (duv <= dxy && duv <= dxu && duv <= dxv && duv <= dyu && duv <= dyv) k=1; */
+/* else if (dxu <= dxy && dxu <= dxv && dxu <= dyu && dxu <= dyv && dxu <= duv) k=2; */
+/* else if (dyv <= dxy && dyv <= dxu && dyv <= dxv && dyv <= dyu && dyv <= duv) k=2; */
+/* else if (dxv <= dxy && dxv <= dxu && dxv <= dyu && dxv <= dyv && dxv <= duv) k=3; */
+/* else if (dyu <= dxy && dyu <= dxu && dyu <= dxv && dyu <= dyv && dyu <= duv) k=3; */
+ //Rprintf("%d\t%d\t%d\t%d\t%d\t%d\t\n", xy, xu, xv, yu, yv, uv);
+ //Rprintf("dxy = %f\tdxu = %f\tdyu = %f\n", dxy, dxu, dyu);
+ //Rprintf("D[xv] = %f\tD[yv] = %f\tD[uv] = %f\n", D[xv], D[yv], D[uv]);
+ /* switch (k) { */
+/* case 1 : A = dxv + dyu; B = dxu + dyv; C = dxy + duv; break; */
+/* case 2 : A = dxv + dyu; B = dxy + duv; C = dxu + dyv; break; */
+/* case 3 : A = dxu + dyv; B = dxy + duv; C = dxv + dyu; break; */
+/* } */
+ //Rprintf("A = %f\tB = %f\tC = %f\n", A, B, C);
+ A = dxv + dyu; B = dxu + dyv; C = dxy + duv;
+ //Rprintf("A = %f\tB = %f\tC = %f\n", A, B, C);
+ if (A == B && B == C) delta = 0; else while (1) {
+ if (C <= B && B <= A) {delta = (A - B)/(A - C); break;}
+ if (B <= C && C <= A) {delta = (A - C)/(A - B); break;}
+ if (A <= C && C <= B) {delta = (B - C)/(B - A); break;}
+ if (C <= A && A <= B) {delta = (B - A)/(B - C); break;}
+ if (A <= B && B <= C) {delta = (C - B)/(C - A); break;}
+ if (B <= A && A <= C) {delta = (C - A)/(C - B); break;}
+ }
+ /* if (delta == 1) i = nb - 1; else */
+ i = delta * nb;
+ //Rprintf("delta = %f\ti = %d\n", delta, i);
+ counts[i] += 1;
+ deltabar[x] += delta;
+ deltabar[y] += delta;
+ deltabar[u] += delta;
+ deltabar[v] += delta;
+ }
+ }
+ }
+ }
+}