/*please excuse the multiple uses of the same letters: A,D, etc.*/
void assignDownWeightsUp(edge *etest, node *vtest, node *va, edge *back, node *cprev, double oldD_AB, double coeff, double **A, double ***swapWeights)
{
edge *par, *sib, *skew;
double D_AC, D_BD, D_AB, D_CD;
par = etest->tail->parentEdge;
skew = siblingEdge(etest);
if (NULL == back) /*first recursive call*/
{
if (NULL == par)
return;
else /*start the process of assigning weights recursively*/
{
assignDownWeightsUp(par,vtest,va,etest,va,A[va->index][vtest->index],0.5,A,swapWeights);
assignDownWeightsSkew(skew,vtest,va,etest,va,A[va->index][vtest->index],0.5,A,swapWeights);
}
}
else /*second or later recursive call*/
{
sib = siblingEdge(back);
D_BD = A[vtest->index][etest->head->index]; /*straightforward*/
D_CD = A[sib->head->index][etest->head->index]; /*this one too*/
D_AC = A[sib->head->index][back->head->index] + coeff*(A[sib->head->index][va->index]
- A[sib->head->index][vtest->index]);
D_AB = 0.5*(oldD_AB + A[vtest->index][cprev->index]);
swapWeights[0][vtest->index][etest->head->index] = swapWeights[0][vtest->index][back->head->index] + (D_AC + D_BD - D_AB - D_CD);
if (NULL != par)
{
assignDownWeightsUp(par,vtest,va,etest,sib->head,D_AB,0.5*coeff,A,swapWeights);
assignDownWeightsSkew(skew,vtest,va,etest,sib->head,D_AB,0.5*coeff,A,swapWeights);
}
}
}
/* Assigns values to array swapWeights
* swapWeights[0][j][k] will be the value of removing the tree below the
* edge whose head node has index j and reattaching it to split the edge
* whose head has the index k
* swapWeights[1][j][k] will be the value of removing the tree above the
* edge whose head node has index j and reattaching it to split the edge
* whose head has the index k */
void assignSPRWeights (node *vtest, double **A, double ***swapWeights)
{
edge *etest, *left, *right, *sib, *par;
etest = vtest->parentEdge;
left = vtest->leftEdge;
right = vtest->rightEdge;
par = etest->tail->parentEdge;
sib = siblingEdge (etest);
if (NULL != par)
assignDownWeightsUp (par, vtest, sib->head, NULL, NULL, 0.0, 1.0, A, swapWeights);
if (NULL != sib)
assignDownWeightsSkew (sib, vtest, sib->tail, NULL, NULL, 0.0, 1.0, A, swapWeights);
/* Assigns values for moving subtree rooted at vtest, starting with
* edge parental to tail of edge parental to vtest */
if (NULL != left)
{
assignUpWeights (left, vtest, right->head, NULL, NULL, 0.0, 1.0, A, swapWeights);
assignUpWeights (right, vtest, left->head, NULL, NULL, 0.0, 1.0, A, swapWeights);
}
return;
}
