A software development team is exploring parallel programming paradigms to optimize the performance of their computational$-$intensive application. Discuss the use cases of parallel programming in various domains, such as scientific computing, machine learning, and computer graphics. Illustrate how parallel programming techniques can exploit the parallelism offered by massive multi$-$core GPU architectures to accelerate computations and improve application performance. Provide examples of parallel programming models, such as SIMD $($Single Instruction, Multiple Data$)$ and SIMT $($Single Instruction, Multiple Threads$),$ and discuss their applicability in different scenarios.