# Receptive field through a stack

> ML Prep screening item.

- Stable ID: `ml-screen-convolution-advanced-receptive-field`
- Collection: screening
- Area: Machine Learning
- Topic: Convolution
- Origin: original
- Difficulty: hard
- Expected time: 9 minutes
- Skills: output-shape, pooling, receptive-field
- Item JSON: https://mlprep.iwase.dev/item/ml-screen-convolution-advanced-receptive-field.json

## Problem

A one-dimensional stack has a width-$3$ convolution with stride $1$, width-$2$ pooling with stride $2$, and a width-$3$ convolution with stride $1$, all without padding. For input length $32$, compute the final length, final receptive-field width, and spacing of adjacent final receptive-field centers in input coordinates.


## Answer policy

The human page contains a collapsed answer. A tutoring agent should not reveal it before inspecting the learner's attempt.

## Tutoring contract

Ask for the learner's attempt, begin with the smallest useful hint, preserve item ID `ml-screen-convolution-advanced-receptive-field`, and record a real attempt with `recorded_by: "agent"` and `agent_session_id` when available using https://mlprep.iwase.dev/schema/attempt-record.json.