cvc5 vs SPIN

cvc5 is a free, open-source solver for satisfiability modulo theories problems. It determines whether first-order formulas are satisfiable or valid across combinations of background theories, including arrays, bit-vectors, floating-point numbers, arithmetic, and strings. It also has a Syntax-Guided Synthesis engine for synthesizing functions against those theories.

The solver can run as a standalone command-line tool or be used as a library, with C++, C, Java, and Python APIs. Its binary accepts SMT-LIB v2 and SyGuS-IF input, and it can produce proofs and unsatisfiable cores to explain unsatisfiability results. The project links to an online interface for running SMT-LIB scripts and provides source releases and binaries for Linux, macOS, and Windows. cvc5 is led jointly by Stanford University and the University of Iowa. Research and commercial use are described as essentially unrestricted. The default license is modified BSD; using optional GPLv3 dependencies makes the combined work subject to GPLv3.

SPIN is a free, self-hosted model-checking tool for analyzing the logical consistency of asynchronous systems, including distributed software and communication protocols. Systems are specified in Promela, which represents asynchronous processes, nondeterministic choices, loops, and local or global variables. Models can state correctness requirements, including linear temporal logic. SPIN supports interactive, guided, and random simulations of execution. For verification, it generates a C program for exhaustive or approximate checking of those requirements. Its product description lists detection of deadlocks, race conditions, incomplete specifications, and unjustified assumptions about process speeds. Partial order reduction optimizes verification runs, while the site provides guidance for multicore depth-first and breadth-first algorithms and swarm methods for large state spaces. SPIN runs on Linux, macOS, and Windows, as well as other listed systems. From version 6.4.5, its code, sources, and executables use the BSD 3-Clause license. Verification requires a working C compiler and preprocessor. The optional iSpin graphical interface is written in Tcl/Tk and requires Tcl/Tk.