Обновить путь до:
mallet_path = 'C:/mallet/mallet-2.0.8/bin/mallet.bat'
и измените блокнот mallet.bat в папке mallet 2.0.8 на:
@echo off
rem This batch file serves as a wrapper for several
rem MALLET command line tools.
if not "%MALLET_HOME%" == "" goto gotMalletHome
echo MALLET requires an environment variable MALLET_HOME.
goto :eof
:gotMalletHome
set MALLET_CLASSPATH=C:\mallet\mallet-2.0.8\class;C:\mallet\mallet-2.0.8\lib\mallet-deps.jar
set MALLET_MEMORY=1G
set MALLET_ENCODING=UTF-8
set CMD=%1
shift
set CLASS=
if "%CMD%"=="import-dir" set CLASS=cc.mallet.classify.tui.Text2Vectors
if "%CMD%"=="import-file" set CLASS=cc.mallet.classify.tui.Csv2Vectors
if "%CMD%"=="import-svmlight" set CLASS=cc.mallet.classify.tui.SvmLight2Vectors
if "%CMD%"=="info" set CLASS=cc.mallet.classify.tui.Vectors2Info
if "%CMD%"=="train-classifier" set CLASS=cc.mallet.classify.tui.Vectors2Classify
if "%CMD%"=="classify-dir" set CLASS=cc.mallet.classify.tui.Text2Classify
if "%CMD%"=="classify-file" set CLASS=cc.mallet.classify.tui.Csv2Classify
if "%CMD%"=="classify-svmlight" set CLASS=cc.mallet.classify.tui.SvmLight2Classify
if "%CMD%"=="train-topics" set CLASS=cc.mallet.topics.tui.TopicTrainer
if "%CMD%"=="infer-topics" set CLASS=cc.mallet.topics.tui.InferTopics
if "%CMD%"=="evaluate-topics" set CLASS=cc.mallet.topics.tui.EvaluateTopics
if "%CMD%"=="prune" set CLASS=cc.mallet.classify.tui.Vectors2Vectors
if "%CMD%"=="split" set CLASS=cc.mallet.classify.tui.Vectors2Vectors
if "%CMD%"=="bulk-load" set CLASS=cc.mallet.util.BulkLoader
if "%CMD%"=="run" set CLASS=%1 & shift
if not "%CLASS%" == "" goto gotClass
echo Mallet 2.0 commands:
echo import-dir load the contents of a directory into mallet instances (one per file)
echo import-file load a single file into mallet instances (one per line)
echo import-svmlight load a single SVMLight format data file into mallet instances (one per line)
echo info get information about Mallet instances
echo train-classifier train a classifier from Mallet data files
echo classify-dir classify data from a single file with a saved classifier
echo classify-file classify the contents of a directory with a saved classifier
echo classify-svmlight classify data from a single file in SVMLight format
echo train-topics train a topic model from Mallet data files
echo infer-topics use a trained topic model to infer topics for new documents
echo evaluate-topics estimate the probability of new documents given a trained model
echo prune remove features based on frequency or information gain
echo split divide data into testing, training, and validation portions
echo bulk-load for big input files, efficiently prune vocabulary and import docs
echo Include --help with any option for more information
goto :eof
:gotClass
set MALLET_ARGS=
:getArg
if "%1"=="" goto run
set MALLET_ARGS=%MALLET_ARGS% %1
shift
goto getArg
:run
"C:\Program Files\Java\jdk-12\bin\java" -ea -Dfile.encoding=%MALLET_ENCODING% -classpath %MALLET_CLASSPATH% %CLASS% %MALLET_ARGS%
:eof
в командной строке это были полезные команды, чтобы выяснить, что происходит:
notepad mallet.bat
java
C:\Program Files\Java\jdk-12\bin\java
dir /OD
cd %userdir%
cd %userpath%
cd\
cd users
cd your_username
cd appdata\local\temp\2
dir /OD
проблема в том, что java не установлен правильно или путь не включает java, а путь к классу молотка не определен правильно. Более подробная информация здесь: https://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html. Это решило мою ошибку, надеюсь, это поможет кому-то еще:)