gpt-4

GPT-4 is OpenAI's multimodal large language model released in March 2023, representing a significant advancement in AI capability across reasoning, knowledge, coding, creativity, and safety compared to its predecessors. GPT-4 accepts both text and image inputs (with text output), making it OpenAI's first multimodal production model. OpenAI disclosed minimal architectural details, but GPT-4 is widely reported to be a Mixture of Experts (MoE) model with approximately 1.8 trillion total parameters across 16 experts. GPT-4's key improvements over GPT-3.5 include: substantially improved reasoning (scoring in the 90th percentile on the bar exam versus GPT-3.5's 10th percentile, and dramatically higher scores on SAT, GRE, AP exams, and professional certifications), reduced hallucination (40% less likely to produce factually incorrect content according to OpenAI's internal evaluations), longer context windows (8K and 32K token variants, later expanded to 128K in GPT-4 Turbo), multimodal understanding (analyzing images, charts, diagrams, screenshots, and handwritten text), improved multilingual performance, better instruction following and nuanced control through system messages, and enhanced safety (82% less likely to respond to disallowed content requests). GPT-4 variants include: GPT-4 Turbo (faster, cheaper, 128K context, knowledge cutoff April 2024), GPT-4o ("omni" — natively multimodal across text, vision, and audio with significantly faster inference and lower cost), and GPT-4o mini (smaller, cost-optimized variant for simpler tasks). GPT-4 powers ChatGPT Plus, Microsoft Copilot, and thousands of applications via API. It established new benchmarks across coding (HumanEval), reasoning (MMLU, HellaSwag), and professional exams, and its capability level catalyzed the competitive landscape — prompting Google to accelerate Gemini, Anthropic to develop Claude 3, and Meta to invest heavily in open-source alternatives.