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Equation 12 · Part 1 · Measuring What a RAG System Retrieves, Not Just What It Answers

Symbol i

reli\mathrm{rel}_i
ii

What this part means

a position index.

Its job in the formula

i is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Where the article explains it

where reli\mathrm{rel}_i is the graded relevance of the result at position i and IDCG@\mathrm{IDCG@}k is the DCG of the ideal ordering, so the ratio is bounded near one regardless of how many relevant documents exist for a given query.

The passage around this formula

where reli\mathrm{rel}_i is the graded relevance of the result at position i and IDCG@\mathrm{IDCG@}k is the DCG of the ideal ordering, so the ratio is bounded near one regardless of how many relevant documents exist for a given query. The logarithmic discount encodes a specific judgement about attention: a relevant document at position one is worth far more than the same…

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.