---
title: "Examples: Online Adaptive Search"
author: "Philip I. Pavlik Jr."
date: "2026-06-08"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Examples: Online Adaptive Search}
  %\VignetteEngine{knitr::rmarkdown}
  \usepackage[utf8]{inputenc}
---

```{r setup}
source("lkt-vignette-setup.R")

print_fast_fit_table <- function(base, grid, optimized = NULL) {
  null_loglike <- base$loglike / (1 - base$r2)
  rows <- list(
    data.frame(
      model = "LibLinear",
      loglike = base$loglike,
      delta_loglike = 0,
      r2 = base$r2,
      delta_r2 = 0,
      stringsAsFactors = FALSE
    ),
    data.frame(
      model = "Online grid start",
      loglike = grid$loglike,
      delta_loglike = grid$loglike - base$loglike,
      r2 = 1 - grid$loglike / null_loglike,
      delta_r2 = (1 - grid$loglike / null_loglike) - base$r2,
      stringsAsFactors = FALSE
    )
  )
  if (!is.null(optimized)) {
    rows[[length(rows) + 1L]] <- data.frame(
      model = "Online six-parameter search",
      loglike = optimized$loglike,
      delta_loglike = optimized$delta_loglike,
      r2 = optimized$r2,
      delta_r2 = optimized$delta_r2,
      stringsAsFactors = FALSE
    )
  }
  print(do.call(rbind, rows))
}
```

# Load data

```{r bundled-data}
val <- prepare_largeraw_sample()
```

# Static LKT Baseline

```{r static-lkt-baseline}
model_static_logistic <- LKT(
  data = val,
  interc = TRUE,
  dualfit = FALSE,
  factrv = 1e11,
  components = c(
    "Anon.Student.Id",
    "KC..Default.",
    "KC..Default."
  ),
  features = c("logitdec", "logsuc", "recency"),
  fixedpars = c(0.98, 0.24)
)
print(model_static_logistic$coefs)
```

# Legacy Fast Objective Check

```{r fast-online-input}
fast_input <- LKTOnlineSimpleAdaptiveInput(
  model_static_logistic,
  val
)
cat("native compiled evaluator available:", fast_input$native_available, "\n")

par_zero <- c(fast_input$beta_start, alpha_recency = 0, alpha_logsuc = 0)
fit_zero <- LKTOnlineSimpleAdaptiveEval(par_zero, fast_input, return_details = TRUE)
check_close(
  "alpha-zero loglike matches LibLinear",
  fit_zero$loglike,
  model_static_logistic$loglike,
  tolerance = 1e-6
)
check_close(
  "alpha-zero max prediction difference",
  max(abs(fit_zero$pred - model_static_logistic$prediction)),
  0,
  tolerance = 1e-12
)
```

# General Online Adaptive Adapter

```{r fast-online-model-adapter}
val_short <- val #[seq_len(min(220, nrow(val))), ]
model_static_short <- LKT(
  data = val_short,
  interc = TRUE,
  dualfit = FALSE,
  factrv = 1e11,
  components = c(
    "Anon.Student.Id",
    "KC..Default.",
    "KC..Default."
  ),
  features = c("logitdec", "logsuc", "recency"),
  fixedpars = c(0.98, 0.24)
)
model_fast_online_adapter <- LKT(
  data = val_short,
  interc = TRUE,
  dualfit = FALSE,
  factrv = 1e11,
  components = c(
    "Anon.Student.Id",
    "KC..Default.",
    "KC..Default."
  ),
  features = c("logitdec", "logsuc", "recency"),
  fixedpars = c(0.98, 0.24),
  model = "online_adaptive",
  model_options = list(
    online_mode = "alpha_only",
    beta_alpha_terms = c(
      "recencyKC..Default.",
      "logsucKC..Default."
    ),
    nonlinear_alpha_terms = c(
      "recency|KC..Default.|para",
      "logitdec|Anon.Student.Id|para"
    ),
    alpha_lower = -1,
    alpha_upper = 1,
    require_native = FALSE,
    maxit = 12,
    factr = 1e7
  )
)
cat("adapter model name:", model_fast_online_adapter$model_name, "\n")
cat("adapter loglike:", model_fast_online_adapter$loglike, "\n")
cat(
  "adapter delta loglike:",
  model_fast_online_adapter$loglike - model_static_short$loglike,
  "\n"
)
cat("adapter parameters:\n")
print(model_fast_online_adapter$model$par)
cat("adaptive beta terms:\n")
print(model_fast_online_adapter$model$adaptive_beta_terms)
cat("adaptive nonlinear terms:\n")
print(model_fast_online_adapter$model$adaptive_nonlinear_terms)
print(model_fast_online_adapter$coefs)
```

# General Native Beta Adapter

```{r native-beta-adapter}
model_native_beta_adapter <- LKT(
  data = val_short,
  interc = TRUE,
  dualfit = FALSE,
  factrv = 1e11,
  components = c(
    "Anon.Student.Id",
    "KC..Default.",
    "KC..Default."
  ),
  features = c("logitdec", "logsuc", "recency"),
  fixedpars = c(0.98, 0.24),
  model = "online_adaptive",
  model_options = list(
    online_mode = "alpha_only",
    beta_alpha_terms = c("logitdecAnon.Student.Id"),
    alpha_lower = -1,
    alpha_upper = 1,
    require_native = TRUE,
    maxit = 2,
    factr = 1e7
  )
)
cat("native beta evaluator available:",
    model_native_beta_adapter$model$native_available, "\n")
cat("native beta alpha:\n")
print(model_native_beta_adapter$model$alpha)
```