mat OutputLayer::backprop(const mat label) {
y = label;
delta = costd(y, a, z);
grad = pa.t() * delta;
// regularization
grad = grad + lambda * W;
// compute next layer delta
mat newdelta = delta * W.t();
return newdelta;
}
//*************************************************************************
void findbestcorr(double **newimage, int ncols, int *bounds, int n, double *origvec,int morigvec,double *transform, int ntransform,int iter) {
double *tvec=NULL;
double *t=transform+n*ntransform;
int boundsvec[2];
double score;
double delta=INITDELTA;
int i;
int precibest=-1;
double *newscore=(double *) malloc(2*ntransform*sizeof(double));
int ibestscore;
score=cost(newimage,newimage[n],bounds,bounds+2*n, ncols, n)-costd(transform,ncols,ntransform,n,iter);
//mexPrintf("score original: %lf pour %d t:%lf costd:%lf\n",score,n,t[0],costd(transform,ncols,ntransform,n,iter));
while(delta>=1) {
//mexPrintf("Delta : %f \n",delta);
ibestscore=-1;
for(i=0;i<ntransform;i++) {
if(precibest!=2*i+1) {
t[i]+=delta;
//mexPrintf("before ==");
transformvec(origvec,morigvec,tvec,boundsvec,t,ntransform);
//mexPrintf(" ==after t1:%lf b1:%d b2:%d t:%lf\n",tvec[0],boundsvec[0],boundsvec[1],transform[i]);
newscore[2*i]=cost(newimage,tvec,bounds,boundsvec, ncols, n)-costd(transform,ncols,ntransform,n,iter);
if(newscore[2*i]>score) {
score=newscore[2*i];
ibestscore=2*i;
}
t[i]-=delta;
}
//mexPrintf("score : %f i:%d bi:%d :\n",newscore[2*i],i,ibestscore);
if(precibest!=2*i) {
t[i]-=delta;
//mexPrintf("before ==");
transformvec(origvec,morigvec,tvec,boundsvec,t,ntransform);
//mexPrintf(" ==after t1:%lf b1:%d b2:%d t:%lf\n",tvec[0],boundsvec[0],boundsvec[1],transform[i]);
newscore[2*i+1]=cost(newimage,tvec,bounds,boundsvec, ncols, n)-costd(transform,ncols,ntransform,n,iter);
if(newscore[2*i+1]>score) {
score=newscore[2*i+1];
ibestscore=2*i+1;
}
//mexPrintf("score : %f i:%d bi:%d :\n",newscore[2*i+1],i,ibestscore);
t[i]+=delta;
}
}
if(ibestscore==-1)
delta=0.5*delta;
else{
if(ibestscore%2==0)
t[ibestscore/2]+=delta;
else
t[ibestscore/2]-=delta;
}
precibest=ibestscore;
}
//mexPrintf("score final: %lf t:%lf costd:%lf\n",score,t[0],costd(transform,ncols,ntransform,n,iter));
free(newscore);
transformvec(origvec, morigvec, tvec, boundsvec, t, ntransform);
free(newimage[n]);
newimage[n]=tvec;
bounds[2*n]=boundsvec[0];
bounds[2*n+1]=boundsvec[1];
}
