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条文字查询。双编码器的图像输出不依赖当前查询，所以可以先计算图库矩阵 $V\\in\\mathbb R^{N\\times d}$，查询到来时只计算文字向量 $u$，再用 $Vu$ 得分。这把“理解输入的深度编码”和“在现有表示中比较”分成两段。","sha256":"0d52d45b91d64683943b3870efe42eb2211cb249baaa5d700568f83f16ac824f","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"retrieval-cache-and-evaluation","title":"检索到底复用了什么，又省去了什么？"},"page":{"id":"reading-opening","title":"检索为什么能缓存：每张图编码一次，查询再比较","number":1},"sectionTitle":"检索为什么能缓存：每张图编码一次，查询再比较","currentQuestion":"检索为什么能缓存：每张图编码一次，查询再比较","sourceSlides":[],"knowledgeBlock":null,"formulas":[{"latex":"N","definitionContext":"检索为什么能缓存：每张图编码一次，查询再比较"},{"latex":"Q","definitionContext":"检索为什么能缓存：每张图编码一次，查询再比较"},{"latex":"V\\in\\mathbb R^{N\\times 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查询仍要与全部 $N$ 向量做点积；float32 图库矩阵占 $4Nd$ 字节。本例 $24\\times512\\times4=49,152$ 字节，不含图片、模型、ID 与索引。改变 checkpoint、预处理或图片内容需要重建对应缓存；只新增文字候选不改变旧图片向量。","sha256":"a0b9c4c8d9eebe422e20a0d9595195dc58efc43923716e264bd41dc0bfb60c5d","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"retrieval-cache-and-evaluation","title":"检索到底复用了什么，又省去了什么？"},"page":{"id":"reading-opening","title":"检索为什么能缓存：每张图编码一次，查询再比较","number":1},"sectionTitle":"检索为什么能缓存：每张图编码一次，查询再比较","currentQuestion":"检索为什么能缓存：每张图编码一次，查询再比较","sourceSlides":[],"knowledgeBlock":null,"formulas":[{"latex":"N","definitionContext":"检索为什么能缓存：每张图编码一次，查询再比较"},{"latex":"4Nd","definitionContext":"检索为什么能缓存：每张图编码一次，查询再比较"},{"latex":"24\\times512\\times4=49,152","definitionContext":"检索为什么能缓存：每张图编码一次，查询再比较"}],"previousBlock":"b-2e26938ea192ee911379e72e","nextBlock":"b-c72dbf2647c42d8ec4037148","prerequisites":[{"id":"b-7c842ded1098a18239e9968d","url":"#b-7c842ded1098a18239e9968d","role":"section-title"},{"id":"b-f94d48b6db527affc11defc0","url":"#b-f94d48b6db527affc11defc0","role":"problem-context"}],"relatedBlocks":[{"id":"b-f98faa11966d02406e93c0cb","url":"#b-f98faa11966d02406e93c0cb","relation":"figure-and-explanation"}]},{"id":"b-c72dbf2647c42d8ec4037148","type":"p","scope":"retrieval-cache-interface","url":"https://codingai-lec03.pages.dev/course/blocks/retrieval-cache-interface.html#b-c72dbf2647c42d8ec4037148","content":"P59 使用已有 24 项缓存显示猫查询的前三项：`chelsea-center90`、`chelsea-full`、`chelsea-right90`。24 项其实来自六张照片的四种相关裁剪，不能当成 24 张独立语义样本。它足以观察排名与缓存复用；更大的索引工程属于第八讲和 LAB12 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张来源照片 × 4 个相关视图 = 24 项；查询：“a photo of a cat.”；文字编码一次；与 24 个已保存图像向量比较；1   chelsea-center90；2   chelsea-full；3   chelsea-right90；已有结果：精确检索的前三项都是猫图变体；复用 2026-09-22 本地真实 CLIP 缓存；24 项含相关裁剪，不是 24 个独立来源。本轮未运行模型。\n\n查询对应的前三张结果来自已经保存的真实 CLIP 缓存。 查看对应图解状态\n\n- 6 张来源照片 × 4 个相关视图 = 24 项\n- 查询：“a photo of a cat.”\n- 文字编码一次\n- 与 24 个已保存图像向量比较\n- 1 chelsea-center90\n- 2 chelsea-full\n- 3 chelsea-right90\n- 已有结果：精确检索的前三项都是猫图变体\n- 复用 2026-09-22 本地真实 CLIP 缓存；24 项含相关裁剪，不是 24 个独立来源。本轮未运行模型。查询对应的前三张结果来自已经保存的真实 CLIP 缓存。 [查看对应图解状态](/#/l3-r2-p59/0)[查看完整图解](/#/l3-r2-p59/0)","sha256":"043e052363a715dc27a99d9b09d9147a12bb987e2132f4e6a8528adf72775fc7","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"retrieval-cache-and-evaluation","title":"检索到底复用了什么，又省去了什么？"},"page":{"id":"reading-opening","title":"检索为什么能缓存：每张图编码一次，查询再比较","number":1},"sectionTitle":"检索为什么能缓存：每张图编码一次，查询再比较","currentQuestion":"检索为什么能缓存：每张图编码一次，查询再比较","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"figure":{"caption":"查询对应的前三张结果来自已经保存的真实 CLIP 缓存。 查看对应图解状态","labels":["6 张来源照片 × 4 个相关视图 = 24 项","查询：“a photo of a cat.”","文字编码一次","与 24 个已保存图像向量比较","1   chelsea-center90","2   chelsea-full","3   chelsea-right90","已有结果：精确检索的前三项都是猫图变体","复用 2026-09-22 本地真实 CLIP 缓存；24 项含相关裁剪，不是 24 个独立来源。本轮未运行模型。"],"description":"查询对应的前三张结果来自已经保存的真实 CLIP 缓存。 查看对应图解状态6 张来源照片 × 4 个相关视图 = 24 项查询：“a photo of a cat.”文字编码一次与 24 个已保存图像向量比较1 chelsea-center902 chelsea-full3 chelsea-right90已有结果：精确检索的前三项都是猫图变体复用 2026-09-22 本地真实 CLIP 缓存；24 项含相关裁剪，不是 24 个独立来源。本轮未运行模型。","evidenceIdentity":"查询对应的前三张结果来自已经保存的真实 CLIP 缓存。 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继续阅读与实验","sha256":"2b9ccef7e1220e2250cceff1abd8bdd736b42f8da5a223f26b029f44b962e807","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"retrieval-cache-and-evaluation","title":"检索到底复用了什么，又省去了什么？"},"page":{"id":"reading-opening","title":"检索为什么能缓存：每张图编码一次，查询再比较","number":1},"sectionTitle":"检索为什么能缓存：每张图编码一次，查询再比较","currentQuestion":"检索为什么能缓存：每张图编码一次，查询再比较","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-f98faa11966d02406e93c0cb","nextBlock":null,"prerequisites":[{"id":"b-7c842ded1098a18239e9968d","url":"#b-7c842ded1098a18239e9968d","role":"section-title"},{"id":"b-f94d48b6db527affc11defc0","url":"#b-f94d48b6db527affc11defc0","role":"problem-context"}],"relatedBlocks":[{"id":"b-f98faa11966d02406e93c0cb","url":"#b-f98faa11966d02406e93c0cb","relation":"figure-and-explanation"}]}]}