# RCAD

## RCell : a new data structure, a refined CAD

An RCAD is a list
(LEVEL, CHILD, ASSIGNED, TRUTH, SAMPLE, INDX, SIGNPF, HOWTV, DEGSUB,
MULSUB, INCELL), with the following meanings:

- LEVEL - the level of the cell.
- CHILD - a list of RCell data structures, the children.
- ASSIGNED - Assignment flag (for parallel execution only).
- TRUTH - the truth value of the cell: TRUE, FALSE, or UNDET.
- SAMPLE - a sample point data structure.
- INDX - the index of the cell as a list.
- SIGNPF - a list (S_1,...,S_k), where k is the LEVEL of the cell.
S_i is a list (s_1,...,s_n) where n is the number of k-i+1 level
projection factors, and s_j is the sign of ... well here I change
things. The n projection factors at some level m are
(P_m,i_1, P_m,i_2, ... , P_m,i_n), where i_1 < i_2 < ... < i_n.
So s_j is the sign of P_i,i_{k-i+1} in the cell.
- HOWTV - how the truth value was assigned, the possibilities
are BYTEV = trial evaluation, BYPRP = propogation,
BYEQC = equational constraint, and NOTDET = not determined.
- DEGSUB - List of degrees of substituted projection factors.
- MULSUB - List of multiplicities of substituted projection factors.
- INCELL - the cell in the qepcad CAD which contains this RCELL.
- OSPFLAG - a flag that equals 1 if this cell's sample point was a
sample point from the original CAD.

Last modified: Tue Jan 19 10:33:19 EST 1999