Teradata Package for R Function Reference | 17.00 - HMMDecoder - Teradata Package for R - Look here for syntax, methods and examples for the functions included in the Teradata Package for R.

HMMDecoder

Description

The HMMDecoder function finds the state sequence with the highest probability, given the learned model and observed sequences.

Usage

  td_hmm_decoder_mle (
      init.state.prob = NULL,
      state.transition.prob = NULL,
      emission.prob = NULL,
      observation = NULL,
      state.model.key = NULL,
      state.key = NULL,
      state.prob.key = NULL,
      trans.model.key = NULL,
      trans.from.key = NULL,
      trans.to.key = NULL,
      trans.prob.key = NULL,
      emit.model.key = NULL,
      emit.state.key = NULL,
      emit.observed.key = NULL,
      emit.prob.key = NULL,
      model.key = NULL,
      sequence.key = NULL,
      observed.key = NULL,
      sequence.max.size = 2147483647,
      skip.key = NULL,
      accumulate = NULL,
      observation.sequence.column = NULL,
      init.state.prob.sequence.column = NULL,
      state.transition.prob.sequence.column = NULL,
      emission.prob.sequence.column = NULL,
      observation.partition.column = NULL,
      init.state.prob.partition.column = NULL,
      state.transition.prob.partition.column = NULL,
      emission.prob.partition.column = NULL,
      observation.order.column = NULL,
      init.state.prob.order.column = NULL,
      state.transition.prob.order.column = NULL,
      emission.prob.order.column = NULL
  )

Arguments

init.state.prob	Required Argument. Specifies a tbl_teradata that contains the initial state information.
init.state.prob.partition.column	Required Argument. Specifies the Partition By columns for argument "init.state.prob". Values to this argument can be provided as vector, if multiple columns are used for partition. Types: character OR vector of Strings (character)
init.state.prob.order.column	Optional Argument. Specifies the Order By columns for argument "init.state.prob". Values to this argument can be provided as vector, if multiple columns are used for ordering. Types: character OR vector of Strings (character)
state.transition.prob	Required Argument. Specifies a tbl_teradata that contains the state transition information.
state.transition.prob.partition.column	Required Argument. Specifies the Partition By columns for argument "state.transition.prob". Values to this argument can be provided as vector, if multiple columns are used for partition. Types: character OR vector of Strings (character)
state.transition.prob.order.column	Optional Argument. Specifies the Order By columns for argument "state.transition.prob". Values to this argument can be provided as vector, if multiple columns are used for ordering. Types: character OR vector of Strings (character)
emission.prob	Required Argument. Specifies a tbl_teradata that contains the emission probability information.
emission.prob.partition.column	Required Argument. Specifies the Partition By columns for argument "emission.prob". Values to this argument can be provided as vector, if multiple columns are used for partition. Types: character OR vector of Strings (character)
emission.prob.order.column	Optional Argument. Specifies the Order By columns for argument "emission.prob". Values to this argument can be provided as vector, if multiple columns are used for ordering. Types: character OR vector of Strings (character)
observation	Required Argument. Specifies a tbl_teradata that contains the observation information.
observation.partition.column	Required Argument. Specifies the Partition By columns for argument "observation". Values to this argument can be provided as vector, if multiple columns are used for partition. Types: character OR vector of Strings (character)
observation.order.column	Required Argument. Specifies the Order By columns for argument "observation". Values to this argument can be provided as vector, if multiple columns are used for ordering. Types: character OR vector of Strings (character)
state.model.key	Required Argument. Specifies the name of the model attribute column in the "init.state.prob" tbl_teradata. Types: character OR vector of Strings (character)
state.key	Required Argument. Specifies the name of the state attribute column in the "init.state.prob" tbl_teradata. Types: character OR vector of Strings (character)
state.prob.key	Required Argument. Specifies the name of the initial probability column in the "init.state.prob" tbl_teradata. Types: character OR vector of Strings (character)
trans.model.key	Required Argument. Specifies the name of the model attribute column in the "state.transition.prob" tbl_teradata. Types: character OR vector of Strings (character)
trans.from.key	Required Argument. Specifies the name of the source state transition column in the "state.transition.prob" tbl_teradata. Types: character OR vector of Strings (character)
trans.to.key	Required Argument. Specifies the name of the target state transition column in the "state.transition.prob" tbl_teradata. Types: character OR vector of Strings (character)
trans.prob.key	Required Argument. Specifies the name of the state transition probability column in the "state.transition.prob" tbl_teradata. Types: character OR vector of Strings (character)
emit.model.key	Required Argument. Specifies the name of the model attribute column in the "emission.prob" tbl_teradata. Types: character OR vector of Strings (character)
emit.state.key	Required Argument. Specifies the name of the state attribute column in the "emission.prob" tbl_teradata. Types: character OR vector of Strings (character)
emit.observed.key	Required Argument. Specifies the name of the observation attribute column in the "emission.prob" tbl_teradata. Types: character OR vector of Strings (character)
emit.prob.key	Required Argument. Specifies the name of the emission probability column in the "emission.prob" tbl_teradata. Types: character OR vector of Strings (character)
model.key	Required Argument. Specifies the name of the column that contains the model attribute. It must match one of the column names specified in the "observation.partition.column" argument. Types: character
sequence.key	Required Argument. Specifies the name of the column that contains the sequence attribute. It must match one of the column names specified in the "observation.partition.column" argument. Types: character
observed.key	Required Argument. Specifies the name of the column that contains the observed symbols. Note: Observed symbols are case-sensitive. Types: character
sequence.max.size	Optional Argument. Specifies the maximum length (in rows) of a sequence in the "observation" tbl_teradata. Default Value: 2147483647 Types: integer
skip.key	Optional Argument. Specifies the name of the column whose values determine whether the function skips the row. The function skips the row if the value is "true", "yes", "y", or "1". The function does not skip the row if the value is "false", "f", "no", "n", "0", or NULL. Types: character
accumulate	Optional Argument. Specifies the names of the columns in the "observation" tbl_teradata tbl_teradata that the function copies to the output tbl_teradata. Types: character OR vector of Strings (character)
observation.sequence.column	Optional Argument. Specifies the vector of column(s) that uniquely identifies each row of the input argument "observation". The argument is used to ensure deterministic results for functions which produce results that vary from run to run. Types: character OR vector of Strings (character)
init.state.prob.sequence.column	Optional Argument. Specifies the vector of column(s) that uniquely identifies each row of the input argument "init.state.prob". The argument is used to ensure deterministic results for functions which produce results that vary from run to run. Types: character OR vector of Strings (character)
state.transition.prob.sequence.column	Optional Argument. Specifies the vector of column(s) that uniquely identifies each row of the input argument "state.transition.prob". The argument is used to ensure deterministic results for functions which produce results that vary from run to run. Types: character OR vector of Strings (character)
emission.prob.sequence.column	Optional Argument. Specifies the vector of column(s) that uniquely identifies each row of the input argument "emission.prob". The argument is used to ensure deterministic results for functions which produce results that vary from run to run. Types: character OR vector of Strings (character)

Value

Function returns an object of class "td_hmm_decoder_mle" which is a named list containing object of class "tbl_teradata".
Named list member can be referenced directly with the "$" operator using name: result.

Examples

  
    # Get the current context/connection
    con <- td_get_context()$connection

    # Load example data.
    loadExampleData("hmmsupervised_example", "customer_loyalty")
    loadExampleData("hmmunsupervised_example", "loan_prediction")

    # Example 1 - This example uses loan status updates to build a td_hmm_supervised_mle()
    # function and then predict loan defaults.
    loadExampleData("hmmdecoder_example", "test_loan_prediction")

    # Create object(s) of class "tbl_teradata".
    loan_prediction <- tbl(con, "loan_prediction")

    td_hmm_unsup_out <- td_hmm_unsupervised_mle(vertices=loan_prediction,
                                  vertices.partition.column=c('model_id','seq_id'),
                                  vertices.order.column='seq_vertex_id',
                                  sequence.key='seq_id',
                                  observed.key='observed_id',
                                  model.key='model_id',
                                  hidden.states.num=3
    )

    test_loan_prediction <- tbl(con, "test_loan_prediction")

    td_hmm_decoder_out1 <- td_hmm_decoder_mle(
                           init.state.prob = td_hmm_unsup_out$output.initialstate.table,
                           init.state.prob.partition.column = c("model_id"),
                           state.transition.prob = td_hmm_unsup_out$output.statetransition.table,
                           state.transition.prob.partition.column = c("model_id"),
                           emission.prob = td_hmm_unsup_out$output.emission.table,
                           emission.prob.partition.column = c("model_id"),
                           observation = test_loan_prediction,
                           observation.partition.column = c("model_id "),
                           observation.order.column = c("model_id", "seq_id", "seq_vertex_id"),
                           state.model.key = "model_id",
                           state.key = "state",
                           state.prob.key = "probability",
                           trans.model.key = "model_id",
                           trans.from.key = "from_state",
                           trans.to.key = "to_state",
                           trans.prob.key = "probability",
                           emit.model.key = "model_id",
                           emit.state.key = "state",
                           emit.observed.key = "observed",
                           emit.prob.key = "probability",
                           model.key = "model_id",
                           sequence.key = "seq_id",
                           observed.key = "observed_id",
                           accumulate = c("seq_vertex_id")
                          )

    # Example 2 - This example uses the output of a td_hmm_supervised_mle() function with the
    # input to determine the loyalty levels of customers from the new sequence of purchases.
    loadExampleData("hmmdecoder_example", "customer_loyalty_newseq")
    customer_loyalty <- tbl(con, "customer_loyalty")

    td_hmm_sup_out <- td_hmm_supervised_mle(vertices=customer_loyalty,
                                    vertices.partition.column=c('user_id','seq_id'),
                                    vertices.order.column=c('user_id','seq_id','purchase_date'),
                                    state.key='loyalty_level',
                                    observed.key='observation',
                                    sequence.key='seq_id',
                                    model.key='user_id'
                                   )

    customer_loyalty_newseq <- tbl(con, "customer_loyalty_newseq")

    td_hmm_decoder_out2 <- td_hmm_decoder_mle(
                             init.state.prob = td_hmm_sup_out$output.initialstate.table,
                             init.state.prob.partition.column = c("user_id"),
                             state.transition.prob = td_hmm_sup_out$output.statetransition.table,
                             state.transition.prob.partition.column = c("user_id"),
                             emission.prob = td_hmm_sup_out$output.emission.table,
                             emission.prob.partition.column = c("user_id"),
                             observation = customer_loyalty_newseq,
                             observation.partition.column = c("user_id"),
                             observation.order.column = c("user_id", "seq_id", "purchase_date"),
                             state.model.key = "user_id",
                             state.key = "state",
                             state.prob.key = "probability",
                             trans.model.key = "user_id",
                             trans.from.key = "from_state",
                             trans.to.key = "to_state",
                             trans.prob.key = "probability",
                             emit.model.key = "user_id",
                             emit.state.key = "state",
                             emit.observed.key = "observed",
                             emit.prob.key = "probability",
                             model.key = "user_id",
                             sequence.key = "seq_id",
                             observed.key = "observation",
                             accumulate = "purchase_date"
                            )

    # Example 3 - Part of Speech Tagging example
    loadExampleData("hmmdecoder_example", "initial", "state_transition", "emission", "phrases")
    initial <- tbl(con, "initial")
    state_transition <- tbl(con, "state_transition")
    emission <- tbl(con, "emission")
    phrases <- tbl(con, "phrases")

    td_hmm_decoder_out3 <- td_hmm_decoder_mle(init.state.prob = initial,
                                         init.state.prob.partition.column = c("model"),
                                         state.transition.prob = state_transition,
                                         state.transition.prob.partition.column = c("model"),
                                         emission.prob = emission,
                                         emission.prob.partition.column = c("model"),
                                         observation = phrases,
                                         observation.partition.column = c("model"),
                                         observation.order.column = c("model", "phrase_id"),
                                         state.model.key = "model",
                                         state.key = "tag",
                                         state.prob.key = "probability",
                                         trans.model.key = "model",
                                         trans.from.key = "from_tag",
                                         trans.to.key = "to_tag",
                                         trans.prob.key = "probability",
                                         emit.model.key = "model",
                                         emit.state.key = "tag",
                                         emit.observed.key = "word",
                                         emit.prob.key = "probability",
                                         model.key = "model",
                                         sequence.key = "phrase_id",
                                         observed.key = "word"
                                         )

    # Example 4 - This example uses td_hmm_supervised_mle() function to find the propensity
    # of customer churn,
    # given the actions or transactions of a bank customer.
    loadExampleData("hmmdecoder_example", "churn_initial", "churn_state_transition",
                    "churn_emission", "churn_data")
    churn_initial <- tbl(con, "churn_initial")
    churn_state_transition <- tbl(con, "churn_state_transition")
    churn_emission <- tbl(con, "churn_emission")
    churn_data <- tbl(con, "churn_data")

    td_hmm_decoder_out4 <- td_hmm_decoder_mle(init.state.prob = churn_initial,
                                         init.state.prob.partition.column = c("model"),
                                         state.transition.prob = churn_state_transition,
                                         state.transition.prob.partition.column = c("model"),
                                         emission.prob = churn_emission,
                                         emission.prob.partition.column = c("model"),
                                         observation = churn_data,
                                         observation.partition.column = c("model"),
                                         observation.order.column = c("model","id", "path_id"),
                                         state.model.key = "model",
                                         state.key = "tag",
                                         state.prob.key = "probability",
                                         trans.model.key = "model",
                                         trans.from.key = "from_tag",
                                         trans.to.key = "to_tag",
                                         trans.prob.key = "probability",
                                         emit.model.key = "model",
                                         emit.state.key = "state",
                                         emit.observed.key = "observed",
                                         emit.prob.key = "probability",
                                         model.key = "model",
                                         sequence.key = "id",
                                         observed.key = "action",
                                         accumulate = c("path_id")
                                         )