22. A computer-based system for querying a collection of documents according to a document layout, comprising: (i) a data input module configured to receive into memory: a set of document indexes, a set of representative blocks, a set of document index clusters, a set of representative indexes, and a document layout query; (ii) a document query module configured to: extract layout blocks from the document layout query, project the extracted layout blocks from the document layout query onto the set of representative blocks to generate a query index, compute the similarity between the query index and each of the representative indexes in the set of document index clusters by using a ranking function, identify the document index cluster containing the representative index having the greatest similarity as the top document index cluster, and compute the similarity between each document index in the top document index cluster and the query index by using the ranking function; and (iii) a document ranking module configured to: maintain an ordered list of the top k documents based on the computed similarity between each document index in the top document index cluster and the query index, and output the ordered list.
22. A computer-based system for querying a collection of documents according to a document layout, comprising: (i) a data input module configured to receive into memory: a set of document indexes, a set of representative blocks, a set of document index clusters, a set of representative indexes, and a document layout query; (ii) a document query module configured to: extract layout blocks from the document layout query, project the extracted layout blocks from the document layout query onto the set of representative blocks to generate a query index, compute the similarity between the query index and each of the representative indexes in the set of document index clusters by using a ranking function, identify the document index cluster containing the representative index having the greatest similarity as the top document index cluster, and compute the similarity between each document index in the top document index cluster and the query index by using the ranking function; and (iii) a document ranking module configured to: maintain an ordered list of the top k documents based on the computed similarity between each document index in the top document index cluster and the query index, and output the ordered list. 23. The system of claim 22 , wherein the system outputs the ordered list to an associated client terminal.