Lower-dimensional subspace approximation of a dataset

1. A computer-implemented method for performing semantic document analysis, the method comprising:

determining a semantic analysis matrix corresponding to a set of documents, wherein each entry of the semantic analysis matrix indicates a number of times a respective term of a set of terms appears in a corresponding document in the set of documents;

determining a lower-dimensional compressed matrix from the semantic analysis matrix, wherein the lower-dimensional compressed matrix corresponds to a document subset of the set of documents that is representative of the set of documents within an accuracy tolerance;

determining a first vector representation of a first document and a second vector representation of a second document;

determining a first lower-dimensional vector representation of the first document using the first vector representation and the lower-dimensional compressed matrix and a second lower-dimensional vector representation of the second document using the second vector representation and the lower-dimensional compressed matrix;

determining, using the first lower-dimensional vector representation and the second lower-dimensional vector representation, a similarity metric associated with the first document and the second document;

determining that the similarity metric satisfies a threshold value; and

classifying the first document and the second document in a same document cluster.

2. The computer-implemented method of claim 1 , wherein determining the lower-dimensional compressed matrix comprises:

determining a set of leverage scores corresponding to rows of the semantic analysis matrix; and

sampling a subset of the rows of the semantic analysis matrix based at least in part on a corresponding subset of the set of leverage scores.

3. The computer-implemented method of claim 2 , wherein determining the lower-dimensional compressed matrix further comprises:

determining a target rank parameter;

determining the accuracy tolerance;

determining, based at least in part on the target rank parameter and the accuracy tolerance, a number of times to sample the semantic analysis matrix to obtain the subset of rows.

4. The computer-implemented method of claim 3 , wherein determining the lower-dimensional compressed matrix further comprises projecting each of the rows of the semantic analysis matrix onto a linear combination of the sampled subset of rows.

5. The computer-implemented method of claim 4 , wherein the number of times to sample the semantic analysis matrix is a first number of times and the subset is a first subset, and wherein determining the lower-dimensional compressed matrix further comprises:

determining a set of distances from the rows of the semantic analysis matrix to the linear combination based at least in part on the projecting;

determining, based at least in part on the target rank parameter, the accuracy tolerance, and the set of distances, a second number of times to sample the semantic analysis matrix to obtain the subset of rows;

sampling the rows of the semantic analysis matrix the second number of times to obtain a second subset of the rows of the semantic analysis matrix; and

generating the lower-dimensional compressed matrix using at least a portion of a combined subset of the rows of the semantic analysis matrix, the combined subset containing the first subset and the second subset.

6. The computer-implemented method of claim 5 , wherein determining the lower-dimensional compressed matrix further comprises determining an optimal subspace of the combined subset, wherein a number of dimensions of the optimal subspace is the target rank parameter.

7. The computer-implemented method of claim 1 , wherein the set of terms is selected based at least in part on a predefined impact on semantic meaning.

8. A system for performing semantic document analysis, the system comprising:

at least one memory storing computer-executable instructions; and

at least one processor configured to access the at least one memory and execute the computer-executable instructions to:

determine a semantic analysis matrix corresponding to a set of documents, wherein each entry of the semantic analysis matrix indicates a number of times a respective term of a set of terms appears in a corresponding document in the set of documents;

determine a lower-dimensional compressed matrix from the semantic analysis matrix, wherein the lower-dimensional compressed matrix corresponds to a document subset of the set of documents that is representative of the set of documents within an accuracy tolerance;

determine a first vector representation of a first document and a second vector representation of a second document;

determine a first lower-dimensional vector representation of the first document using the first vector representation and the lower-dimensional compressed matrix and a second lower-dimensional vector representation of the second document using the second vector representation and the lower-dimensional compressed matrix;

determine, using the first lower-dimensional vector representation and the second lower-dimensional vector representation, a similarity metric associated with the first document and the second document;

determine that the similarity metric satisfies a threshold value; and

classify the first document and the second document in a same document cluster.

9. The system of claim 8 , wherein the at least one processor is configured to determine the lower-dimensional compressed matrix by executing the computer-executable instructions to:

determine a set of leverage scores corresponding to rows of the semantic analysis matrix; and

sample a subset of the rows of the semantic analysis matrix based at least in part on a corresponding subset of the set of leverage scores.

10. The system of claim 9 , wherein the at least one processor is further configured to determine the lower-dimensional compressed matrix by executing the computer-executable instructions to:

determine a target rank parameter;

determine the accuracy tolerance;

determine, based at least in part on the target rank parameter and the accuracy tolerance, a number of times to sample the semantic analysis matrix to obtain the subset of rows.

11. The system of claim 10 , wherein the at least one processor is further configured to determine the lower-dimensional compressed matrix by executing the computer-executable instructions to project each of the rows of the semantic analysis matrix onto a linear combination of the sampled subset of rows.

12. The system of claim 11 , wherein the number of times to sample the semantic analysis matrix is a first number of times and the subset is a first subset, and wherein the at least one processor is further configured to determine the lower-dimensional compressed matrix by executing the computer-executable instructions to:

determine a set of distances from the rows of the semantic analysis matrix to the linear combination based at least in part on the projecting;

determine, based at least in part on the target rank parameter, the accuracy tolerance, and the set of distances, a second number of times to sample the semantic analysis matrix to obtain the subset of rows;

sample the rows of the semantic analysis matrix the second number of times to obtain a second subset of the rows of the semantic analysis matrix; and

generate the lower-dimensional compressed matrix using at least a portion of a combined subset of the rows of the semantic analysis matrix, the combined subset containing the first subset and the second subset.

13. The system of claim 12 , wherein the at least one processor is further configured to determine the lower-dimensional compressed matrix by executing the computer-executable instructions to determine an optimal subspace of the combined subset, wherein a number of dimensions of the optimal subspace is the target rank parameter.

14. The system of claim 8 , wherein the set of terms is selected based at least in part on a predefined impact on semantic meaning.

15. A computer program product for performing semantic document analysis, the computer program product comprising a storage medium readable by a processing circuit, the storage medium storing instructions executable by the processing circuit to cause a method to be performed, the method comprising:

determining a semantic analysis matrix corresponding to a set of documents, wherein each entry of the semantic analysis matrix indicates a number of times a respective term of a set of terms appears in a corresponding document in the set of documents;

determining a lower-dimensional compressed matrix from the semantic analysis matrix, wherein the lower-dimensional compressed matrix corresponds to a document subset of the set of documents that is representative of the set of documents within an accuracy tolerance;

determining a first vector representation of a first document and a second vector representation of a second document;

determining a first lower-dimensional vector representation of the first document using the first vector representation and the lower-dimensional compressed matrix and a second lower-dimensional vector representation of the second document using the second vector representation and the lower-dimensional compressed matrix;

determining, using the first lower-dimensional vector representation and the second lower-dimensional vector representation, a similarity metric associated with the first document and the second document;

determining that the similarity metric satisfies a threshold value; and

classifying the first document and the second document in a same document cluster.

16. The computer program product of claim 15 , wherein determining the lower-dimensional compressed matrix comprises:

determining a set of leverage scores corresponding to rows of the semantic analysis matrix; and

sampling a subset of the rows of the semantic analysis matrix based at least in part on a corresponding subset of the set of leverage scores.

17. The computer program product of claim 16 , wherein determining the lower-dimensional compressed matrix further comprises:

determining a target rank parameter;

determining an accuracy tolerance;

determining, based at least in part on the target rank parameter and the accuracy tolerance, a number of times to sample the semantic analysis matrix to obtain the subset of rows.

18. The computer program product of claim 17 , wherein determining the lower-dimensional compressed matrix further comprises projecting each of the rows of the semantic analysis matrix onto a linear combination of the sampled subset of rows.

19. The computer program product of claim 18 , wherein the number of times to sample the semantic analysis matrix is a first number of times and the subset is a first subset, and wherein determining the lower-dimensional compressed matrix further comprises:

determining a set of distances from the rows of the semantic analysis matrix to the linear combination based at least in part on the projecting;

determining, based at least in part on the target rank parameter, the accuracy tolerance, and the set of distances, a second number of times to sample the semantic analysis matrix to obtain the subset of rows;

sampling the rows of the semantic analysis matrix the second number of times to obtain a second subset of the rows of the semantic analysis matrix; and

generating the lower-dimensional compressed matrix using at least a portion of a combined subset of the rows of the semantic analysis matrix, the combined subset containing the first subset and the second subset.

20. The computer program product of claim 19 , wherein determining the lower-dimensional compressed matrix further comprises determining an optimal subspace of the combined subset, wherein a number of dimensions of the optimal subspace is the target rank parameter.