The Boolean Satisfiability (SAT) problem is the key problem in computer theory and application. A parallel multi‐thread SAT solver named pprobSAT+ on a configurable hardware is proposed. In the algorithm, multithreads are executed simultaneously to hide the circuit stagnate. In order to improve the working frequency and throughput of the SAT solver, the deep pipeline strategy is adopted. When all data stored in block random access memory of the field programmable gate array, the solver can achieve maximum performance. If partial data are stored in the external memory, the size of the problem instances the SAT solver can be greatly improved. The experimental results show that the speedup of three‐thread SAT solver is approximately 2.4 times with single thread, and shows that the pprobSAT+ have achieved substantial improvement while a solution is found.
The Boolean satisfiability (SAT) problem is the key problem in computer theory and application. A novel algorithm is introduced to implement a SLS hardware solver called probSAT+. The algorithm has no complex heuristic, and it only depends on the concepts of preprocessing technology, probability distribution and centralized search. Through constraining the initial assignments of the variables, the number of flipped variables was reduced while the solver finding a solution. Moreover, the algorithm no longer adopts some non-continuous if-then-else decisions, but depends on a single continuous function f(x,v). The flipping probability is not obtained by complex calculations, instead being selected by looking up tables, which effectively improves the performance of the solver. As far as we know, the probability distribution selection strategy descripted by hardware description language is firstly adopted by hardware SAT solver, which can be easily transplanted to any programmable logic device. The experimental results show that the probSAT+ solver is generally lower than the advanced software solver in the number of flips (up to 9.8 × 10 6 ), and the speedup is approximately 2.6 times with single thread, which shows that the probSAT+ has better results with fewer variables flipping times when a solution can be found. In addition, the success ratio of the solver in finding a solution of the problem in a suitable time is 100%.
Aims
Our objective was to explore whether the accuracy of the transitional zone index (TZI) for outflow tract ventricular arrhythmias (OT‐VAs) origin is affected by cardiac rotation and the additive value of interventricular septum angle (IVSa) obtained from coronary computed tomography angiography (CCTA).
Methods
Standard 12‐lead ECGs of OT‐VAs with inferior axis in consecutive patients undergoing both CCTA examination and successful ablation were retrospectively analyzed. The IVSa was defined as an angle between the long axis of IVS and sagittal axis of the body from CCTA.
Results
64 patients (31 men; mean age 54.2 ± 11.6 years) were enrolled. The OT‐VAs exhibited right ventricular outflow tract origin in 46 (71.9%) patients and 36 (78.3%) were diagnosed correctly by TZI. The left ventricular outflow tract origin OT‐VAs was observed in 18 (28.1%) patients and 16 (88.9%) were diagnosed correctly by TZI. The patients were then divided into TZI correct group (n = 52) and TZI incorrect group (n = 12). In the TZI incorrect group, 11/12 (91.7%) cases were R/S transition in lead V3 with the TZ score during premature ventricular contractions [2.8(2.5−3.4)], and the TZI between −1.5 and 0. The IVSa was significantly larger in the TZI incorrect group than correct group (52.0 ± 6.9° vs. 39.0 ± 6.1°; p < .0001). The IVSa ≥46° predicted TZI incorrect with 92% sensitivity, 94% specificity, and 94% accuracy.
Conclusion
The IVSa is a novel cardiac rotation index that reliably improves TZI to differentiate the OT‐VAs origin, especially for the OT‐VAs with lead V3 R/S transition.
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