## ----setup, include = FALSE-----------------------------------------------------------------------
knitr::opts_chunk$set(echo = TRUE, fig.align = "center", out.width = "100%")
knitr::opts_chunk$set(comment = "#>")
old_options <- options(width = 100)

## -------------------------------------------------------------------------------------------------
library(spifa)
library(sf)

## -------------------------------------------------------------------------------------------------
set.seed(1)
nobs <- 20
nitems <- 5

raw <- data.frame(
  id = seq_len(nobs),
  wealth = rnorm(nobs),
  lon = runif(nobs, -71.70, -71.68),
  lat = runif(nobs, -7.06, -7.04),
  item1 = rbinom(nobs, 1, 0.1) == 1,
  item2 = rbinom(nobs, 1, 0.2) == 1,
  item3 = rbinom(nobs, 1, 0.3) == 1,
  item4 = rbinom(nobs, 1, 0.4) == 1,
  item5 = rbinom(nobs, 1, 0.5) == 1
)
raw

## -------------------------------------------------------------------------------------------------
# get items as a matrix
items <- subset(raw, select = grep("^item", names(raw))) |>
  as.matrix() |>
  unname()
# create data.frame and geo-reference it
data <- data.frame(items = I(items), wealth = raw$wealth, x = raw$lon, y = raw$lat) |>
    st_as_sf(coords = c("x", "y"), crs = 4326)
data

## -------------------------------------------------------------------------------------------------
data$items

## -------------------------------------------------------------------------------------------------
spifa(items ~ wealth, data = data, nfactors = 2, niter = 5)

## -------------------------------------------------------------------------------------------------
data <- data.frame(wealth = raw$wealth, x = raw$lon, y = raw$lat) |>
    st_as_sf(coords = c("x", "y"), crs = 4326)
data$items <- items
data

## -------------------------------------------------------------------------------------------------
spifa(items ~ wealth, data = data, nfactors = 2, niter = 5)

## -------------------------------------------------------------------------------------------------
data_na <- data
data_na$items[1:5, 1] <- NA

fit_na <- spifa(items ~ 1, data = data_na, nfactors = 2, ngp = 0, niter = 5)
fit_na

## -------------------------------------------------------------------------------------------------
data_na <- data
data_na$wealth[1:5] <- NA

fit_na <- spifa(items ~ wealth, data = data_na, nfactors = 2, ngp = 0, niter = 5)
fit_na

## ----include = FALSE----------------------------------------------------------
options(old_options)