{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":42848,"title":"Lambert's W","description":"Matlab cody does not support lambertw. Try to create a lambert's w function yourself.\r\n\r\nLambert's W is the function that solves \r\n\r\n  x*exp(x) = A;\r\n\r\ngiven the value of A.\r\n\r\nRead more about Lambert's W \u003chttps://en.wikipedia.org/wiki/Lambert_W_function here\u003e.\r\n\r\nThough it is not particularly appropriate for this particular function, consider using \u003chttps://en.wikipedia.org/wiki/Newton's_method Newton-Raphson's method\u003e. Since all test cases will converge if starting with 0.\r\n\r\nThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.","description_html":"\u003cp\u003eMatlab cody does not support lambertw. Try to create a lambert's w function yourself.\u003c/p\u003e\u003cp\u003eLambert's W is the function that solves\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ex*exp(x) = A;\r\n\u003c/pre\u003e\u003cp\u003egiven the value of A.\u003c/p\u003e\u003cp\u003eRead more about Lambert's W \u003ca href = \"https://en.wikipedia.org/wiki/Lambert_W_function\"\u003ehere\u003c/a\u003e.\u003c/p\u003e\u003cp\u003eThough it is not particularly appropriate for this particular function, consider using \u003ca href = \"https://en.wikipedia.org/wiki/Newton's_method\"\u003eNewton-Raphson's method\u003c/a\u003e. Since all test cases will converge if starting with 0.\u003c/p\u003e\u003cp\u003eThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.\u003c/p\u003e","function_template":"function x = LambertW(A)\r\n  y = log(x);\r\nend","test_suite":"%%\r\nA = 1;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n\r\n%%\r\nA = 6.8;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n\r\n%%\r\nA = 14;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":1,"created_by":12767,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":54,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-05-05T14:37:35.000Z","updated_at":"2026-05-25T00:55:27.000Z","published_at":"2016-05-05T14:38:09.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMatlab cody does not support lambertw. Try to create a lambert's w function yourself.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eLambert's W is the function that solves\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[x*exp(x) = A;]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003egiven the value of A.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eRead more about Lambert's W\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://en.wikipedia.org/wiki/Lambert_W_function\\\"\u003e\u003cw:r\u003e\u003cw:t\u003ehere\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThough it is not particularly appropriate for this particular function, consider using\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://en.wikipedia.org/wiki/Newton's_method\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eNewton-Raphson's method\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e. Since all test cases will converge if starting with 0.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":42848,"title":"Lambert's W","description":"Matlab cody does not support lambertw. Try to create a lambert's w function yourself.\r\n\r\nLambert's W is the function that solves \r\n\r\n  x*exp(x) = A;\r\n\r\ngiven the value of A.\r\n\r\nRead more about Lambert's W \u003chttps://en.wikipedia.org/wiki/Lambert_W_function here\u003e.\r\n\r\nThough it is not particularly appropriate for this particular function, consider using \u003chttps://en.wikipedia.org/wiki/Newton's_method Newton-Raphson's method\u003e. Since all test cases will converge if starting with 0.\r\n\r\nThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.","description_html":"\u003cp\u003eMatlab cody does not support lambertw. Try to create a lambert's w function yourself.\u003c/p\u003e\u003cp\u003eLambert's W is the function that solves\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ex*exp(x) = A;\r\n\u003c/pre\u003e\u003cp\u003egiven the value of A.\u003c/p\u003e\u003cp\u003eRead more about Lambert's W \u003ca href = \"https://en.wikipedia.org/wiki/Lambert_W_function\"\u003ehere\u003c/a\u003e.\u003c/p\u003e\u003cp\u003eThough it is not particularly appropriate for this particular function, consider using \u003ca href = \"https://en.wikipedia.org/wiki/Newton's_method\"\u003eNewton-Raphson's method\u003c/a\u003e. Since all test cases will converge if starting with 0.\u003c/p\u003e\u003cp\u003eThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.\u003c/p\u003e","function_template":"function x = LambertW(A)\r\n  y = log(x);\r\nend","test_suite":"%%\r\nA = 1;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n\r\n%%\r\nA = 6.8;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n\r\n%%\r\nA = 14;\r\nx = LambertW(A);\r\nA_correct = x*exp(x);\r\nassert(abs(A_correct/A-1)\u003c1e-5)\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":1,"created_by":12767,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":54,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-05-05T14:37:35.000Z","updated_at":"2026-05-25T00:55:27.000Z","published_at":"2016-05-05T14:38:09.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMatlab cody does not support lambertw. Try to create a lambert's w function yourself.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eLambert's W is the function that solves\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[x*exp(x) = A;]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003egiven the value of A.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eRead more about Lambert's W\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://en.wikipedia.org/wiki/Lambert_W_function\\\"\u003e\u003cw:r\u003e\u003cw:t\u003ehere\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThough it is not particularly appropriate for this particular function, consider using\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://en.wikipedia.org/wiki/Newton's_method\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eNewton-Raphson's method\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e. Since all test cases will converge if starting with 0.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe relative tolerance for the result of x*exp(x) compared to A is 1e-5.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[{"value":"Functions II","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"newton\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}