fix EMGLLF.c (there was one extra iteration)
[valse.git] / pkg / src / sources / EMGLLF.c
index 86b6060..d2f5a8e 100644 (file)
@@ -1,8 +1,9 @@
 #include "utils.h"
 #include <stdlib.h>
+#include <math.h>
 #include <gsl/gsl_linalg.h>
 
-// TODO: don't recompute indexes every time......
+// TODO: don't recompute indexes ai(...) and mi(...) when possible
 void EMGLLF_core(
        // IN parameters
        const Real* phiInit, // parametre initial de moyenne renormalisé
@@ -20,8 +21,10 @@ void EMGLLF_core(
        Real* phi, // parametre de moyenne renormalisé, calculé par l'EM
        Real* rho, // parametre de variance renormalisé, calculé par l'EM
        Real* pi, // parametre des proportions renormalisé, calculé par l'EM
-       Real* LLF, // log vraisemblance associée à cet échantillon, pour les valeurs estimées des paramètres
+       Real* llh, // (derniere) log vraisemblance associée à cet échantillon,
+                  // pour les valeurs estimées des paramètres
        Real* S,
+       int* affec,
        // additional size parameters
        int n, // nombre d'echantillons
        int p, // nombre de covariables
@@ -32,39 +35,33 @@ void EMGLLF_core(
        copyArray(phiInit, phi, p*m*k);
        copyArray(rhoInit, rho, m*m*k);
        copyArray(piInit, pi, k);
-       zeroArray(LLF, maxi);
        //S is already allocated, and doesn't need to be 'zeroed'
 
-       //Other local variables
+       //Other local variables: same as in R
        Real* gam = (Real*)malloc(n*k*sizeof(Real));
        copyArray(gamInit, gam, n*k);
-       Real* b = (Real*)malloc(k*sizeof(Real));
-       Real* Phi = (Real*)malloc(p*m*k*sizeof(Real));
-       Real* Rho = (Real*)malloc(m*m*k*sizeof(Real));
-       Real* Pi = (Real*)malloc(k*sizeof(Real));
-       Real* gam2 = (Real*)malloc(k*sizeof(Real));
-       Real* pi2 = (Real*)malloc(k*sizeof(Real));
        Real* Gram2 = (Real*)malloc(p*p*k*sizeof(Real));
-       Real* ps = (Real*)malloc(m*k*sizeof(Real));
-       Real* nY2 = (Real*)malloc(m*k*sizeof(Real));
-       Real* ps1 = (Real*)malloc(n*m*k*sizeof(Real));
        Real* ps2 = (Real*)malloc(p*m*k*sizeof(Real));
-       Real* nY21 = (Real*)malloc(n*m*k*sizeof(Real));
-       Real* Gam = (Real*)malloc(n*k*sizeof(Real));
+       Real* b = (Real*)malloc(k*sizeof(Real));
        Real* X2 = (Real*)malloc(n*p*k*sizeof(Real));
        Real* Y2 = (Real*)malloc(n*m*k*sizeof(Real));
+       *llh = -INFINITY;
+       Real* pi2 = (Real*)malloc(k*sizeof(Real));
+       const Real EPS = 1e-15;
+       // Additional (not at this place, in R file)
+       Real* gam2 = (Real*)malloc(k*sizeof(Real));
        Real* sqNorm2 = (Real*)malloc(k*sizeof(Real));
+       Real* detRho = (Real*)malloc(k*sizeof(Real));
        gsl_matrix* matrix = gsl_matrix_alloc(m, m);
        gsl_permutation* permutation = gsl_permutation_alloc(m);
        Real* YiRhoR = (Real*)malloc(m*sizeof(Real));
        Real* XiPhiR = (Real*)malloc(m*sizeof(Real));
-       Real dist = 0.;
-       Real dist2 = 0.;
-       int ite = 0;
-       const Real EPS = 1e-15;
        const Real gaussConstM = pow(2.*M_PI,m/2.);
+       Real* Phi = (Real*)malloc(p*m*k*sizeof(Real));
+       Real* Rho = (Real*)malloc(m*m*k*sizeof(Real));
+       Real* Pi = (Real*)malloc(k*sizeof(Real));
 
-       while (ite < mini || (ite < maxi && (dist >= tau || dist2 >= sqrt(tau))))
+       for (int ite=1; ite<=maxi; ite++)
        {
                copyArray(phi, Phi, p*m*k);
                copyArray(rho, Rho, m*m*k);
@@ -77,7 +74,7 @@ void EMGLLF_core(
                        {
                                //Y2[,mm,r] = sqrt(gam[,r]) * Y[,mm]
                                for (int u=0; u<n; u++)
-                                       Y2[ai(u,mm,r,n,m,k)] = sqrt(gam[mi(u,r,n,k)]) * Y[mi(u,mm,m,n)];
+                                       Y2[ai(u,mm,r,n,m,k)] = sqrt(gam[mi(u,r,n,k)]) * Y[mi(u,mm,n,m)];
                        }
                        for (int i=0; i<n; i++)
                        {
@@ -142,8 +139,8 @@ void EMGLLF_core(
                }
 
                //tant que les proportions sont negatives
-               int kk = 0;
-               int pi2AllPositive = 0;
+               int kk = 0,
+                       pi2AllPositive = 0;
                Real invN = 1./n;
                while (!pi2AllPositive)
                {
@@ -164,33 +161,34 @@ void EMGLLF_core(
                        kk++;
                }
 
-               //(pi.^gamma)*b
+               //sum(pi^gamma * b)
                Real piPowGammaDotB = 0.;
                for (int v=0; v<k; v++)
                        piPowGammaDotB += pow(pi[v],gamma) * b[v];
-               //(pi2.^gamma)*b
+               //sum(pi2^gamma * b)
                Real pi2PowGammaDotB = 0.;
                for (int v=0; v<k; v++)
                        pi2PowGammaDotB += pow(pi2[v],gamma) * b[v];
-               //transpose(gam2)*log(pi2)
-               Real prodGam2logPi2 = 0.;
+               //sum(gam2 * log(pi2))
+               Real gam2DotLogPi2 = 0.;
                for (int v=0; v<k; v++)
-                       prodGam2logPi2 += gam2[v] * log(pi2[v]);
+                       gam2DotLogPi2 += gam2[v] * log(pi2[v]);
+
                //t(m) la plus grande valeur dans la grille O.1^k tel que ce soit décroissante ou constante
-               while (-invN*a + lambda*piPowGammaDotB < -invN*prodGam2logPi2 + lambda*pi2PowGammaDotB
+               while (-invN*a + lambda*piPowGammaDotB < -invN*gam2DotLogPi2 + lambda*pi2PowGammaDotB
                        && kk<1000)
                {
                        Real pow_01_kk = pow(0.1,kk);
                        //pi2 = pi + 0.1^kk * (1/n*gam2 - pi)
                        for (int v=0; v<k; v++)
                                pi2[v] = pi[v] + pow_01_kk * (invN*gam2[v] - pi[v]);
-                       //pi2 was updated, so we recompute pi2PowGammaDotB and prodGam2logPi2
+                       //pi2 was updated, so we recompute pi2PowGammaDotB and gam2DotLogPi2
                        pi2PowGammaDotB = 0.;
                        for (int v=0; v<k; v++)
                                pi2PowGammaDotB += pow(pi2[v],gamma) * b[v];
-                       prodGam2logPi2 = 0.;
+                       gam2DotLogPi2 = 0.;
                        for (int v=0; v<k; v++)
-                               prodGam2logPi2 += gam2[v] * log(pi2[v]);
+                               gam2DotLogPi2 += gam2[v] * log(pi2[v]);
                        kk++;
                }
                Real t = pow(0.1,kk);
@@ -207,59 +205,51 @@ void EMGLLF_core(
                {
                        for (int mm=0; mm<m; mm++)
                        {
+                               Real ps = 0.,
+                                       nY2 = 0.;
+                               // Compute ps, and nY2 = sum(Y2[,mm,r]^2)
                                for (int i=0; i<n; i++)
                                {
-                                       //< X2(i,:,r) , phi(:,mm,r) >
+                                       //< X2[i,,r] , phi[,mm,r] >
                                        Real dotProduct = 0.;
                                        for (int u=0; u<p; u++)
                                                dotProduct += X2[ai(i,u,r,n,p,k)] * phi[ai(u,mm,r,p,m,k)];
-                                       //ps1[i,mm,r] = Y2[i,mm,r] * sum(X2[i,,r] * phi[,mm,r])
-                                       ps1[ai(i,mm,r,n,m,k)] = Y2[ai(i,mm,r,n,m,k)] * dotProduct;
-                                       nY21[ai(i,mm,r,n,m,k)] = Y2[ai(i,mm,r,n,m,k)] * Y2[ai(i,mm,r,n,m,k)];
+                                       //ps = ps + Y2[i,mm,r] * sum(X2[i,,r] * phi[,mm,r])
+                                       ps += Y2[ai(i,mm,r,n,m,k)] * dotProduct;
+                                       nY2 += Y2[ai(i,mm,r,n,m,k)] * Y2[ai(i,mm,r,n,m,k)];
                                }
-                               //ps[mm,r] = sum(ps1[,mm,r])
-                               Real sumPs1 = 0.;
-                               for (int u=0; u<n; u++)
-                                       sumPs1 += ps1[ai(u,mm,r,n,m,k)];
-                               ps[mi(mm,r,m,k)] = sumPs1;
-                               //nY2[mm,r] = sum(nY21[,mm,r])
-                               Real sumNy21 = 0.;
-                               for (int u=0; u<n; u++)
-                                       sumNy21 += nY21[ai(u,mm,r,n,m,k)];
-                               nY2[mi(mm,r,m,k)] = sumNy21;
-                               //rho[mm,mm,r] = (ps[mm,r]+sqrt(ps[mm,r]^2+4*nY2[mm,r]*(gam2[r]))) / (2*nY2[mm,r])
-                               rho[ai(mm,mm,r,m,m,k)] = ( ps[mi(mm,r,m,k)] + sqrt( ps[mi(mm,r,m,k)]*ps[mi(mm,r,m,k)]
-                                       + 4*nY2[mi(mm,r,m,k)] * gam2[r] ) ) / (2*nY2[mi(mm,r,m,k)]);
+                               //rho[mm,mm,r] = (ps+sqrt(ps^2+4*nY2*gam2[r])) / (2*nY2)
+                               rho[ai(mm,mm,r,m,m,k)] = (ps + sqrt(ps*ps + 4*nY2 * gam2[r])) / (2*nY2);
                        }
                }
+
                for (int r=0; r<k; r++)
                {
                        for (int j=0; j<p; j++)
                        {
                                for (int mm=0; mm<m; mm++)
                                {
-                                       //sum(phi[1:(j-1),mm,r] * Gram2[j,1:(j-1),r])
-                                       Real dotPhiGram2 = 0.0;
-                                       for (int u=0; u<j; u++)
-                                               dotPhiGram2 += phi[ai(u,mm,r,p,m,k)] * Gram2[ai(j,u,r,p,p,k)];
-                                       //sum(phi[(j+1):p,mm,r] * Gram2[j,(j+1):p,r])
-                                       for (int u=j+1; u<p; u++)
-                                               dotPhiGram2 += phi[ai(u,mm,r,p,m,k)] * Gram2[ai(j,u,r,p,p,k)];
-                                       //S[j,mm,r] = -rho[mm,mm,r]*ps2[j,mm,r] +
-                                       //  (if(j>1) sum(phi[1:(j-1),mm,r] * Gram2[j,1:(j-1),r]) else 0) +
-                                       //  (if(j<p) sum(phi[(j+1):p,mm,r] * Gram2[j,(j+1):p,r]) else 0)
-                                       S[ai(j,mm,r,p,m,k)] = -rho[ai(mm,mm,r,m,m,k)] * ps2[ai(j,mm,r,p,m,k)] + dotPhiGram2;
-                                       Real pow_pir_gamma = pow(pi[r],gamma);
-                                       if (fabs(S[ai(j,mm,r,p,m,k)]) <= n*lambda*pow_pir_gamma)
-                                               phi[ai(j,mm,r,p,m,k)] = 0;
-                                       else if (S[ai(j,mm,r,p,m,k)] > n*lambda*pow_pir_gamma)
+                                       //sum(phi[-j,mm,r] * Gram2[j,-j,r])
+                                       Real phiDotGram2 = 0.;
+                                       for (int u=0; u<p; u++)
                                        {
-                                               phi[ai(j,mm,r,p,m,k)] = (n*lambda*pow_pir_gamma - S[ai(j,mm,r,p,m,k)])
+                                               if (u != j)
+                                                       phiDotGram2 += phi[ai(u,mm,r,p,m,k)] * Gram2[ai(j,u,r,p,p,k)];
+                                       }
+                                       //S[j,mm,r] = -rho[mm,mm,r]*ps2[j,mm,r] + sum(phi[-j,mm,r] * Gram2[j,-j,r])
+                                       S[ai(j,mm,r,p,m,k)] = -rho[ai(mm,mm,r,m,m,k)] * ps2[ai(j,mm,r,p,m,k)]
+                                               + phiDotGram2;
+                                       Real pirPowGamma = pow(pi[r],gamma);
+                                       if (fabs(S[ai(j,mm,r,p,m,k)]) <= n*lambda*pirPowGamma)
+                                               phi[ai(j,mm,r,p,m,k)] = 0.;
+                                       else if (S[ai(j,mm,r,p,m,k)] > n*lambda*pirPowGamma)
+                                       {
+                                               phi[ai(j,mm,r,p,m,k)] = (n*lambda*pirPowGamma - S[ai(j,mm,r,p,m,k)])
                                                        / Gram2[ai(j,j,r,p,p,k)];
                                        }
                                        else
                                        {
-                                               phi[ai(j,mm,r,p,m,k)] = -(n*lambda*pow_pir_gamma + S[ai(j,mm,r,p,m,k)])
+                                               phi[ai(j,mm,r,p,m,k)] = -(n*lambda*pirPowGamma + S[ai(j,mm,r,p,m,k)])
                                                        / Gram2[ai(j,j,r,p,p,k)];
                                        }
                                }
@@ -270,137 +260,146 @@ void EMGLLF_core(
                // Etape E //
                /////////////
 
+               // Precompute det(rho[,,r]) for r in 1...k
                int signum;
-               Real sumLogLLF2 = 0.0;
-               for (int i=0; i<n; i++)
+               for (int r=0; r<k; r++)
                {
-                       Real minSqNorm2 = INFINITY;
+                       for (int u=0; u<m; u++)
+                       {
+                               for (int v=0; v<m; v++)
+                                       matrix->data[u*m+v] = rho[ai(u,v,r,m,m,k)];
+                       }
+                       gsl_linalg_LU_decomp(matrix, permutation, &signum);
+                       detRho[r] = gsl_linalg_LU_det(matrix, signum);
+               }
 
+               Real sumLogLLH = 0.;
+               for (int i=0; i<n; i++)
+               {
                        for (int r=0; r<k; r++)
                        {
                                //compute Y[i,]%*%rho[,,r]
                                for (int u=0; u<m; u++)
                                {
-                                       YiRhoR[u] = 0.0;
+                                       YiRhoR[u] = 0.;
                                        for (int v=0; v<m; v++)
                                                YiRhoR[u] += Y[mi(i,v,n,m)] * rho[ai(v,u,r,m,m,k)];
                                }
 
-                               //compute X(i,:)*phi(:,:,r)
+                               //compute X[i,]%*%phi[,,r]
                                for (int u=0; u<m; u++)
                                {
-                                       XiPhiR[u] = 0.0;
+                                       XiPhiR[u] = 0.;
                                        for (int v=0; v<p; v++)
                                                XiPhiR[u] += X[mi(i,v,n,p)] * phi[ai(v,u,r,p,m,k)];
                                }
 
                                //compute sq norm || Y(:,i)*rho(:,:,r)-X(i,:)*phi(:,:,r) ||_2^2
-                               sqNorm2[r] = 0.0;
+                               sqNorm2[r] = 0.;
                                for (int u=0; u<m; u++)
                                        sqNorm2[r] += (YiRhoR[u]-XiPhiR[u]) * (YiRhoR[u]-XiPhiR[u]);
-                               if (sqNorm2[r] < minSqNorm2)
-                                       minSqNorm2 = sqNorm2[r];
                        }
-                       Real shift = 0.5*minSqNorm2;
 
-                       Real sumLLF1 = 0.0;
-                       Real sumGamI = 0.0;
+                       Real sumGamI = 0.;
                        for (int r=0; r<k; r++)
                        {
-                               //compute det(rho[,,r]) [TODO: avoid re-computations]
-                               for (int u=0; u<m; u++)
-                               {
-                                       for (int v=0; v<m; v++)
-                                               matrix->data[u*m+v] = rho[ai(u,v,r,m,m,k)];
-                               }
-                               gsl_linalg_LU_decomp(matrix, permutation, &signum);
-                               Real detRhoR = gsl_linalg_LU_det(matrix, signum);
-
-                               //FIXME: det(rho[,,r]) too small(?!). See EMGLLF.R
-                               Gam[mi(i,r,n,k)] = pi[r] * exp(-0.5*sqNorm2[r] + shift) ; //* detRhoR;
-                               sumLLF1 += Gam[mi(i,r,n,k)] / gaussConstM;
-                               sumGamI += Gam[mi(i,r,n,k)];
+                               gam[mi(i,r,n,k)] = pi[r] * exp(-.5*sqNorm2[r]) * detRho[r];
+                               sumGamI += gam[mi(i,r,n,k)];
                        }
-                       sumLogLLF2 += log(sumLLF1);
-                       for (int r=0; r<k; r++)
+
+                       sumLogLLH += log(sumGamI) - log(gaussConstM);
+                       if (sumGamI > EPS) //else: gam[i,] is already ~=0
                        {
-                               //gam[i,] = Gam[i,] / sumGamI
-                               gam[mi(i,r,n,k)] = sumGamI > EPS ? Gam[mi(i,r,n,k)] / sumGamI : 0.;
+                               for (int r=0; r<k; r++)
+                                       gam[mi(i,r,n,k)] /= sumGamI;
                        }
                }
 
                //sumPen = sum(pi^gamma * b)
-               Real sumPen = 0.0;
+               Real sumPen = 0.;
                for (int r=0; r<k; r++)
                        sumPen += pow(pi[r],gamma) * b[r];
-               //LLF[ite] = -sumLogLLF2/n + lambda*sumPen
-               LLF[ite] = -invN * sumLogLLF2 + lambda * sumPen;
-               dist = ite==0 ? LLF[ite] : (LLF[ite] - LLF[ite-1]) / (1.0 + fabs(LLF[ite]));
+               Real last_llh = *llh;
+               //llh = -sumLogLLH/n + lambda*sumPen
+               *llh = -invN * sumLogLLH + lambda * sumPen;
+               Real dist = ite==1 ? *llh : (*llh - last_llh) / (1. + fabs(*llh));
 
                //Dist1 = max( abs(phi-Phi) / (1+abs(phi)) )
-               Real Dist1 = 0.0;
+               Real Dist1 = 0.;
                for (int u=0; u<p; u++)
                {
                        for (int v=0; v<m; v++)
                        {
                                for (int w=0; w<k; w++)
                                {
-                                       Real tmpDist = fabs(phi[ai(u,v,w,p,m,k)]-Phi[ai(u,v,w,p,m,k)]) 
-                                               / (1.0+fabs(phi[ai(u,v,w,p,m,k)]));
+                                       Real tmpDist = fabs(phi[ai(u,v,w,p,m,k)]-Phi[ai(u,v,w,p,m,k)])
+                                               / (1.+fabs(phi[ai(u,v,w,p,m,k)]));
                                        if (tmpDist > Dist1)
                                                Dist1 = tmpDist;
                                }
                        }
                }
                //Dist2 = max( (abs(rho-Rho)) / (1+abs(rho)) )
-               Real Dist2 = 0.0;
+               Real Dist2 = 0.;
                for (int u=0; u<m; u++)
                {
                        for (int v=0; v<m; v++)
                        {
                                for (int w=0; w<k; w++)
                                {
-                                       Real tmpDist = fabs(rho[ai(u,v,w,m,m,k)]-Rho[ai(u,v,w,m,m,k)]) 
-                                               / (1.0+fabs(rho[ai(u,v,w,m,m,k)]));
+                                       Real tmpDist = fabs(rho[ai(u,v,w,m,m,k)]-Rho[ai(u,v,w,m,m,k)])
+                                               / (1.+fabs(rho[ai(u,v,w,m,m,k)]));
                                        if (tmpDist > Dist2)
                                                Dist2 = tmpDist;
                                }
                        }
                }
                //Dist3 = max( (abs(pi-Pi)) / (1+abs(Pi)))
-               Real Dist3 = 0.0;
+               Real Dist3 = 0.;
                for (int u=0; u<n; u++)
                {
                        for (int v=0; v<k; v++)
                        {
-                               Real tmpDist = fabs(pi[v]-Pi[v]) / (1.0+fabs(pi[v]));
+                               Real tmpDist = fabs(pi[v]-Pi[v]) / (1.+fabs(pi[v]));
                                if (tmpDist > Dist3)
                                        Dist3 = tmpDist;
                        }
                }
                //dist2=max([max(Dist1),max(Dist2),max(Dist3)]);
-               dist2 = Dist1;
+               Real dist2 = Dist1;
                if (Dist2 > dist2)
                        dist2 = Dist2;
                if (Dist3 > dist2)
                        dist2 = Dist3;
 
-               ite++;
+               if (ite >= mini && (dist >= tau || dist2 >= sqrt(tau)))
+                       break;
+       }
+
+       //affec = apply(gam, 1, which.max)
+       for (int i=0; i<n; i++)
+       {
+               Real rowMax = 0.;
+               affec[i] = 0;
+               for (int j=0; j<k; j++)
+               {
+                       if (gam[mi(i,j,n,k)] > rowMax)
+                       {
+                               affec[i] = j+1; //R indices start at 1
+                               rowMax = gam[mi(i,j,n,k)];
+                       }
+               }
        }
 
        //free memory
        free(b);
        free(gam);
-       free(Gam);
        free(Phi);
        free(Rho);
        free(Pi);
-       free(ps);
-       free(nY2);
-       free(ps1);
-       free(nY21);
        free(Gram2);
        free(ps2);
+       free(detRho);
        gsl_matrix_free(matrix);
        gsl_permutation_free(permutation);
        free(XiPhiR);