The parallel extension of CONDOR

- The
**main process**on the main computer is the classical non-parallelized version of the algorithm, described at the beginning of Chapter 6. There is an exchange of information with the second/parallel process on steps 4 and 16 of the original algorithm. - The goal of the
**second/parallel process**on the main computer is to increase the quality of the model by using client computers to sample at specific interpolation sites.

- Wait to receive from the second/parallel process on the server a sampling site (a point).
- Evaluate the objective function at this site and return immediately the result to the server.
- Go to step 1.

**A.**- Make a local copy of (and of the associated Lagrange Polynomials )
**B.**- Make a local copy of the dataset .
**C.**- Find the index of the point inside the further away from .
**D.**- Replace
by a better point which will
increase the quality of the approximation of . The
computation of this point is done using Equation 3.38:
is replaced in
by
where
is the solution of the following problem:
(6.7)

**E.**- Ask for an evaluation the objective function at
point
using a free client computer to performs the
evaluation. If there is still a client doing nothing, go back to
step
**C**. **F.**- Wait for a node to complete its evaluation of the objective function .
**G.**- Update
using this new evaluation.
Remove from
. go to step
**C**.

- i.
- Wait for the parallel/second task to enter the step
**F**described above and block the parallel task inside this step**F**for the time needed to perform the points**ii**and**iii**below. - ii.
- Update of using all the points calculated in parallel, discarding the points that are too far away from (at a distance greater than ). This update is performed using technique described in Section 3.4.3 and Section 3.4.4. We will possibly have to update the index of the best point in the dataset and .
- iii.
- Perform operations described in point
**A**&**B**of the parallel/second task algorithm above: `` Copy from . Copy from ``.