Updating Index Information When Adding Or Removing Documents

An electronic device comprising:

• a camera;
• a non-transitory computer-readable memory operatively connected to the camera;
• one or more processors operatively connected to the non-transitory computer-readable memory;
• wherein the non-transitory computer-readable memory comprises a plurality of instructions to index documents by words occurring therein, the plurality of instructions in the non-transitory computer-readable memory comprising:
• first instructions to the one or more processors to receive a new document, to be added to a repository of N existing documents that are indexed by a set of W words in an existing index stored in the non-transitory computer-readable memory;
• wherein the existing index comprises a first set of existing first numbers and a second set of W existing second numbers;
• wherein each of the existing first numbers has a first correspondence to one of N existing documents and each existing second number in the second set of W existing second numbers has a second correspondence to one of W words;
• wherein the first set of the existing first numbers is not associated with any specific word in the set of W words and the second set of W existing second numbers is not associated with any document in the repository of N existing documents;
• second instructions to the one or more processors, to be executed for each existing document that contains a word in common with the new document, to increment an existing first number selected from the first set based on the first correspondence to said existing document, to obtain a new first number in the non-transitory computer-readable memory;
• third instructions to the one or more processors, to be executed for each word that occurs in the new document, to change the existing second number selected from the second set of W existing second numbers based on the second correspondence to said each word, to obtain a new second number in the non-transitory computer-readable memory;
• and
• fourth instructions to the one or more processors, to update the existing index with at least the new first number and at least the new second number, to obtain a new index in the non-transitory computer-readable memory, wherein a superset comprising the new document and the repository of N existing documents is indexed by the set of W words in the new index.

One or more non-transitory computer-readable media comprising a plurality of instructions which, when executed by one or more processors, cause the one or more processors to perform operations, the plurality of instructions comprising

• first instructions to receive a new document, to be added to a repository of N existing documents that are indexed by a set of W words in an existing index;
• wherein the existing index comprises a first set of existing first numbers and a second set of W existing second numbers;
• wherein each of the existing first numbers has a first correspondence to one of N existing documents and each existing second number in the second set of W existing second numbers has a second correspondence to one of W words;
• wherein the first set of the existing first numbers is not associated with any specific word in the set of W words and the second set of W existing second numbers is not associated with any document in N existing documents;
• second instructions to be executed for each existing document that contains a word in common with the new document, to increment an existing first number selected from the first set based on the first correspondence to said existing document, to obtain a new first number;
• third instructions to be executed for each word that occurs in the new document, to change the existing second number selected from the second set of W existing second numbers based on the second correspondence to said each word, to obtain a new second number;
• and
• fourth instructions to update the existing index with at least the new first number and at least the new second number, to obtain a new index, wherein a superset comprising the new document and the repository of N existing documents is indexed by the set of W words in the new index.

An apparatus that indexes documents by words occurring therein, the apparatus comprising:

• means for receiving a new document, to be added to a repository of N existing documents that are indexed by a set of W words in an existing index stored in a non-transitory computer-readable memory;
• wherein the existing index comprises a first set of existing first numbers and a second set of W existing second numbers;
• wherein each of the existing first numbers has a first correspondence to one of N existing documents and each existing second number in the second set of W existing second numbers has a second correspondence to one of W words;
• wherein the first set of the existing first numbers is not associated with any specific word in the set of W words and the second set of W existing second numbers is not associated with any document in the repository of N existing documents;
• means, to be operated for each existing document that contains a word in common with the new document, for incrementing an existing first number selected from the first set based on the first correspondence to said existing document, to obtain a new first number;
• means, to be operated for each word that occurs in the new document, for incrementing the existing second number selected from the second set of W existing second numbers based on the second correspondence to said each word, to obtain a new second number;
• and
• means for updating the existing index with at least the new first number and at least the new second number, to obtain a new index, wherein a superset comprising the new document and the repository of N existing documents is indexed by the set of W words in the new index.