r2rs-stats 0.1.1

// "Whatever you do, work at it with all your heart, as working for the Lord,
// not for human masters, since you know that you will receive an inheritance
// from the Lord as a reward. It is the Lord Christ you are serving."
// (Col 3:23-24)

use std::{
    fmt::{Display, Formatter},
    marker::PhantomData,
};

use nalgebra::DMatrix;
use r2rs_base::traits::{QuantileType, StatisticalSlice};
use strafe_trait::{Model, Statistic, StatisticalEstimate, StatisticalTest};
use strafe_type::{Alpha64, DisplayTable, FloatConstraint, ModelMatrix};

use crate::regression::glm::{family::core::Family, link::core::Link};

/// Fitting Generalized Linear Models
///
/// ## Description:
///
/// ‘glm’ is used to fit generalized linear models, specified by
/// giving a symbolic description of the linear predictor and a
/// description of the error distribution.
///
/// ## Usage:
///
/// glm(formula, family = gaussian, data, weights, subset,
///    na.action, start = NULL, etastart, mustart, offset,
/// control = list(...), model = TRUE, method = "glm.fit",
/// x = FALSE, y = TRUE, singular.ok = TRUE, contrasts = NULL, ...)
///
/// glm.fit(x, y, weights = rep.int(1, nobs),
///    start = NULL, etastart = NULL, mustart = NULL,
///    offset = rep.int(0, nobs), family = gaussian(),
///    control = list(), intercept = TRUE, singular.ok = TRUE)
///
/// ## S3 method for class 'glm'
/// weights(object, type = c("prior", "working"), ...)
///
/// ## Arguments:
///
/// * formula: an object of class ‘"formula"’ (or one that can be coerced to
///   that class): a symbolic description of the model to be
///   fitted.  The details of model specification are given under
///   ‘Details’.
/// * family: a description of the error distribution and link function to
///   be used in the model.  For ‘glm’ this can be a character
///   string naming a family function, a family function or the
///   result of a call to a family function.  For ‘glm.fit’ only
///   the third option is supported.  (See ‘family’ for details of
///   family functions.)
/// * data: an optional data frame, list or environment (or object
///   coercible by ‘as.data.frame’ to a data frame) containing the
///   variables in the model.  If not found in ‘data’, the
///   variables are taken from ‘environment(formula)’, typically
///   the environment from which ‘glm’ is called.
/// * weights: an optional vector of ‘prior weights’ to be used in the
///   fitting process.  Should be ‘NULL’ or a numeric vector.
/// * subset: an optional vector specifying a subset of observations to be
///   used in the fitting process.
/// * na.action: a function which indicates what should happen when the data
///   contain ‘NA’s.  The default is set by the ‘na.action’ setting
///   of ‘options’, and is ‘na.fail’ if that is unset.  The
///   ‘factory-fresh’ default is ‘na.omit’.  Another possible value
///   is ‘NULL’, no action.  Value ‘na.exclude’ can be useful.
/// * start: starting values for the parameters in the linear predictor.
/// * etastart: starting values for the linear predictor.
/// * mustart: starting values for the vector of means.
/// * offset: this can be used to specify an _a priori_ known component to
///   be included in the linear predictor during fitting.  This
///   should be ‘NULL’ or a numeric vector of length equal to the
///   number of cases.  One or more ‘offset’ terms can be included
///   in the formula instead or as well, and if more than one is
///   specified their sum is used.  See ‘model.offset’.
/// * control: a list of parameters for controlling the fitting process.
///   For ‘glm.fit’ this is passed to ‘glm.control’.
/// * model: a logical value indicating whether _model frame_ should be
///   included as a component of the returned value.
/// * method: the method to be used in fitting the model.  The default
///   method ‘"glm.fit"’ uses iteratively reweighted least squares
///   (IWLS): the alternative ‘"model.frame"’ returns the model
///   frame and does no fitting.
///
/// User-supplied fitting functions can be supplied either as a
/// function or a character string naming a function, with a
/// function which takes the same arguments as ‘glm.fit’.  If
/// specified as a character string it is looked up from within
/// the ‘stats’ namespace.
///
/// * x, y: For ‘glm’: logical values indicating whether the response
///   vector and model matrix used in the fitting process should be
///   returned as components of the returned value.
///
/// For ‘glm.fit’: ‘x’ is a design matrix of dimension ‘n * p’,
/// and ‘y’ is a vector of observations of length ‘n’.
///
/// * singular.ok: logical; if ‘FALSE’ a singular fit is an error.
/// * contrasts: an optional list. See the ‘contrasts.arg’ of
///   ‘  model.matrix.default’.
/// * intercept: logical. Should an intercept be included in the _null_
///   model?
/// * object: an object inheriting from class ‘"glm"’.
/// * type: character, partial matching allowed.  Type of weights to
///   extract from the fitted model object.  Can be abbreviated.
/// * ...: For ‘glm’: arguments to be used to form the default ‘control’
///   argument if it is not supplied directly.
///
/// For ‘weights’: further arguments passed to or from other
/// methods.
///
/// ## Details:
///
/// A typical predictor has the form ‘response ~ terms’ where
/// ‘response’ is the (numeric) response vector and ‘terms’ is a
/// series of terms which specifies a linear predictor for ‘response’.
/// For ‘binomial’ and ‘quasibinomial’ families the response can also
/// be specified as a ‘factor’ (when the first level denotes failure
/// and all others success) or as a two-column matrix with the columns
/// giving the numbers of successes and failures.  A terms
/// specification of the form ‘first + second’ indicates all the terms
/// in ‘first’ together with all the terms in ‘second’ with any
/// duplicates removed.
///
/// A specification of the form ‘first:second’ indicates the set of
/// terms obtained by taking the interactions of all terms in ‘first’
/// with all terms in ‘second’.  The specification ‘first*second’
/// indicates the _cross_ of ‘first’ and ‘second’.  This is the same
/// as ‘first + second + first:second’.
///
/// The terms in the formula will be re-ordered so that main effects
/// come first, followed by the interactions, all second-order, all
/// third-order and so on: to avoid this pass a ‘terms’ object as the
/// formula.
///
/// Non-‘NULL’ ‘weights’ can be used to indicate that different
/// observations have different dispersions (with the values in
/// ‘weights’ being inversely proportional to the dispersions); or
/// equivalently, when the elements of ‘weights’ are positive integers
/// w_i, that each response y_i is the mean of w_i unit-weight
/// observations.  For a binomial GLM prior weights are used to give
/// the number of trials when the response is the proportion of
/// successes: they would rarely be used for a Poisson GLM.
///
/// ‘glm.fit’ is the workhorse function: it is not normally called
/// directly but can be more efficient where the response vector,
/// design matrix and family have already been calculated.
///
/// If more than one of ‘etastart’, ‘start’ and ‘mustart’ is
/// specified, the first in the list will be used.  It is often
/// advisable to supply starting values for a ‘quasi’ family, and also
/// for families with unusual links such as ‘gaussian("log")’.
///
/// All of ‘weights’, ‘subset’, ‘offset’, ‘etastart’ and ‘mustart’ are
/// evaluated in the same way as variables in ‘formula’, that is first
/// in ‘data’ and then in the environment of ‘formula’.
///
/// For the background to warning messages about ‘fitted probabilities
/// numerically 0 or 1 occurred’ for binomial GLMs, see Venables &
/// Ripley (2002, pp. 197-8).
///
/// ## Value:
///
/// ‘glm’ returns an object of class inheriting from ‘"glm"’ which
/// inherits from the class ‘"lm"’. See later in this section.  If a
/// non-standard ‘method’ is used, the object will also inherit from
/// the class (if any) returned by that function.
///
/// The function ‘summary’ (i.e., ‘summary.glm’) can be used to obtain
/// or print a summary of the results and the function ‘anova’ (i.e.,
/// ‘anova.glm’) to produce an analysis of variance table.
///
/// The generic accessor functions ‘coefficients’, ‘effects’,
/// ‘fitted.values’ and ‘residuals’ can be used to extract various
/// useful features of the value returned by ‘glm’.
///
/// ‘weights’ extracts a vector of weights, one for each case in the
/// fit (after subsetting and ‘na.action’).
///
/// An object of class ‘"glm"’ is a list containing at least the
/// following components:
///
/// * coefficients: a named vector of coefficients
/// * residuals: the _working_ residuals, that is the residuals in the final
///   iteration of the IWLS fit.  Since cases with zero weights are
///   omitted, their working residuals are ‘NA’.
/// * fitted.values: the fitted mean values, obtained by transforming the
///   linear predictors by the inverse of the link function.
/// * rank: the numeric rank of the fitted linear model.
/// * family: the ‘family’ object used.
/// * linear.predictors: the linear fit on link scale.
/// * deviance: up to a constant, minus twice the maximized log-likelihood.
///   Where sensible, the constant is chosen so that a saturated
///   model has deviance zero.
/// * aic: A version of Akaike's _An Information Criterion_, minus twice
///   the maximized log-likelihood plus twice the number of
///   parameters, computed via the ‘aic’ component of the family.
///   For binomial and Poison families the dispersion is fixed at
///   one and the number of parameters is the number of
///   coefficients.  For gaussian, Gamma and inverse gaussian
///   families the dispersion is estimated from the residual
///   deviance, and the number of parameters is the number of
///   coefficients plus one.  For a gaussian family the MLE of the
///   dispersion is used so this is a valid value of AIC, but for
///   Gamma and inverse gaussian families it is not.  For families
///   fitted by quasi-likelihood the value is ‘NA’.
/// * null.deviance: The deviance for the null model, comparable with
///   ‘deviance’. The null model will include the offset, and an
///   intercept if there is one in the model.  Note that this will
///   be incorrect if the link function depends on the data other
///   than through the fitted mean: specify a zero offset to force
///   a correct calculation.
/// * iter: the number of iterations of IWLS used.
/// * weights: the _working_ weights, that is the weights in the final
///   iteration of the IWLS fit.
/// * prior.weights: the weights initially supplied, a vector of ‘1’s if none
///   were.
/// * df.residual: the residual degrees of freedom.
/// * df.null: the residual degrees of freedom for the null model.
/// * y: if requested (the default) the ‘y’ vector used. (It is a
///   vector even for a binomial model.)
/// * x: if requested, the model matrix.
/// * model: if requested (the default), the model frame.
/// * converged: logical. Was the IWLS algorithm judged to have converged?
/// * boundary: logical. Is the fitted value on the boundary of the
///   attainable values?
/// * call: the matched call.
/// * formula: the formula supplied.
/// * terms: the ‘terms’ object used.
/// * data: the ‘data argument’.
/// * offset: the offset vector used.
/// * control: the value of the ‘control’ argument used.
/// * method: the name of the fitter function used (when provided as a
///   ‘character’ string to ‘glm()’) or the fitter ‘function’ (when
///   provided as that).
/// * contrasts: (where relevant) the contrasts used.
/// * xlevels: (where relevant) a record of the levels of the factors used
///   in fitting.
/// * na.action: (where relevant) information returned by ‘model.frame’ on
///   the special handling of ‘NA’s.
///   In addition, non-empty fits will have components ‘qr’, ‘R’ and
///   ‘effects’ relating to the final weighted linear fit.
///
/// Objects of class ‘"glm"’ are normally of class ‘c("glm", "lm")’,
/// that is inherit from class ‘"lm"’, and well-designed methods for
/// class ‘"lm"’ will be applied to the weighted linear model at the
/// final iteration of IWLS.  However, care is needed, as extractor
/// functions for class ‘"glm"’ such as ‘residuals’ and ‘weights’ do
/// *not* just pick out the component of the fit with the same name.
///
/// If a ‘binomial’ ‘glm’ model was specified by giving a two-column
/// response, the weights returned by ‘prior.weights’ are the total
/// numbers of cases (factored by the supplied case weights) and the
/// component ‘y’ of the result is the proportion of successes.
///
/// ## Fitting functions:
///
/// The argument ‘method’ serves two purposes.  One is to allow the
/// model frame to be recreated with no fitting.  The other is to
/// allow the default fitting function ‘glm.fit’ to be replaced by a
/// function which takes the same arguments and uses a different
/// fitting algorithm.  If ‘glm.fit’ is supplied as a character string
/// it is used to search for a function of that name, starting in the
/// ‘stats’ namespace.
///
/// The class of the object return by the fitter (if any) will be
/// prepended to the class returned by ‘glm’.
///
/// ## Author(s):
///
/// The original R implementation of ‘glm’ was written by Simon Davies
/// working for Ross Ihaka at the University of Auckland, but has
/// since been extensively re-written by members of the R Core team.
///
/// The design was inspired by the S function of the same name
/// described in Hastie & Pregibon (1992).
///
/// ## References:
///
/// Dobson, A. J. (1990) _An Introduction to Generalized Linear
/// Models._ London: Chapman and Hall.
///
/// Hastie, T. J. and Pregibon, D. (1992) _Generalized linear models._
/// Chapter 6 of _Statistical Models in S_ eds J. M. Chambers and T.
/// J. Hastie, Wadsworth & Brooks/Cole.
///
/// McCullagh P. and Nelder, J. A. (1989) _Generalized Linear Models._
/// London: Chapman and Hall.
///
/// Venables, W. N. and Ripley, B. D. (2002) _Modern Applied
/// Statistics with S._ New York: Springer.
///
/// ## See Also:
///
/// ‘anova.glm’, ‘summary.glm’, etc. for ‘glm’ methods, and the
/// generic functions ‘anova’, ‘summary’, ‘effects’, ‘fitted.values’,
/// and ‘residuals’.
///
/// ‘lm’ for non-generalized _linear_ models (which SAS calls GLMs,
/// for ‘general’ linear models).
///
/// ‘loglin’ and ‘loglm’ (package ‘MASS’) for fitting log-linear
/// models (which binomial and Poisson GLMs are) to contingency
/// tables.
///
/// ‘bigglm’ in package ‘biglm’ for an alternative way to fit GLMs to
/// large datasets (especially those with many cases).
///
/// ‘esoph’, ‘infert’ and ‘predict.glm’ have examples of fitting
/// binomial glms.
///
/// ## Examples:
///
/// ```r
/// ## Dobson (1990) Page 93: Randomized Controlled Trial :
/// counts <- c(18,17,15,20,10,20,25,13,12)
/// outcome <- gl(3,1,9)
/// treatment <- gl(3,3)
/// data.frame(treatment, outcome, counts) # showing data
/// glm.D93 <- glm(counts ~ outcome + treatment, family = poisson())
/// anova(glm.D93)
/// summary(glm.D93)
/// ## Computing AIC [in many ways]:
/// (A0 <- AIC(glm.D93))
/// (ll <- logLik(glm.D93))
/// A1 <- -2*c(ll) + 2*attr(ll, "df")
/// A2 <- glm.D93$family$aic(counts, mu=fitted(glm.D93), wt=1) +
///    2 * length(coef(glm.D93))
/// stopifnot(exprs = {
///   all.equal(A0, A1)
///   all.equal(A1, A2)
///   all.equal(A1, glm.D93$aic)
/// })
///
///
/// ## an example with offsets from Venables & Ripley (2002, p.189)
/// utils::data(anorexia, package = "MASS")
///
/// anorex.1 <- glm(Postwt ~ Prewt + Treat + offset(Prewt),
///  family = gaussian, data = anorexia)
/// summary(anorex.1)
///
///
/// # A Gamma example, from McCullagh & Nelder (1989, pp. 300-2)
/// clotting <- data.frame(
/// u = c(5,10,15,20,30,40,60,80,100),
/// lot1 = c(118,58,42,35,27,25,21,19,18),
/// lot2 = c(69,35,26,21,18,16,13,12,12))
/// summary(glm(lot1 ~ log(u), data = clotting, family = Gamma))
/// summary(glm(lot2 ~ log(u), data = clotting, family = Gamma))
/// ## Aliased ("S"ingular) -> 1 NA coefficient
/// (fS <- glm(lot2 ~ log(u) + log(u^2), data = clotting, family = Gamma))
/// tools::assertError(update(fS, singular.ok=FALSE), verbose=interactive())
/// ## -> .. "singular fit encountered"
///
/// ## Not run:
///
/// ## for an example of the use of a terms object as a formula
/// demo(glm.vr)
/// ## End(Not run)
/// ```

#[derive(Clone, Debug)]
pub struct GeneralizedLinearRegression<L: Link, F: Family<L>> {
    pub(crate) x: ModelMatrix,
    pub(crate) y: ModelMatrix,
    pub(crate) w: ModelMatrix,
    pub(crate) alpha: Alpha64,
    pub(crate) family: F,
    pub(crate) _link: PhantomData<L>,
    pub(crate) x1: ModelMatrix,
    pub(crate) b: DMatrix<f64>,
    pub(crate) model_data: (ModelMatrix, DMatrix<f64>, DMatrix<f64>, DMatrix<f64>),
    pub(crate) eta: DMatrix<f64>,
    pub(crate) mu: DMatrix<f64>,
    pub(crate) aic: f64,
    pub(crate) null_deviance: f64,
    pub(crate) residual_deviance: f64,
    pub(crate) final_weights: DMatrix<f64>,
}

impl<L: Link + Clone + 'static, F: Family<L> + Clone + 'static> Display
    for GeneralizedLinearRegression<L, F>
{
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let mut s = self.clone();

        // Write residuals table
        writeln!(f, "Residuals:")?;
        let headers = vec![
            "Minimum".to_string(),
            "1st Quantile".to_string(),
            "Median".to_string(),
            "3rd Quantile".to_string(),
            "Maximum".to_string(),
        ];
        let lines = vec![s
            .residuals()
            .unwrap()
            .matrix()
            .as_slice()
            .quantile(&[0.0, 0.25, 0.5, 0.75, 1.0], QuantileType::S)
            .into_iter()
            .map(|f| f)
            .collect::<Vec<_>>()];
        let row_names = Vec::new();
        writeln!(f, "{}", DisplayTable::new(headers, row_names, lines, None))?;

        // Write coefficients table
        writeln!(f, "Coefficients:")?;
        let headers = vec![
            "Estimate".to_string(),
            "Confidence Interval (L)".to_string(),
            "Confidence Interval (U)".to_string(),
            "T-Value".to_string(),
            "P-Value".to_string(),
        ];
        let mut row_names = Vec::new();
        let mut lines = Vec::new();
        for coef in s.clone().test(&()).unwrap().significant_coef_tests {
            row_names.push(coef.name.clone());
            lines.push(vec![
                coef.estimate(),
                coef.confidence_interval().0,
                coef.confidence_interval().1,
                coef.statistic(),
                coef.probability_value(),
            ]);
        }
        writeln!(f, "{}", DisplayTable::new(headers, row_names, lines, None))?;

        // Write tests table
        writeln!(f, "Tests:")?;
        let headers = vec![
            "Statistic".to_string(),
            "P-Value".to_string(),
            "Alpha".to_string(),
        ];
        let mut row_names = Vec::new();
        let mut lines = Vec::new();

        let rsq = s.determination().unwrap();
        row_names.push("Multiple R-squared (Robust)".to_string());
        lines.push(vec![
            rsq.statistic(),
            rsq.probability_value(),
            rsq.alpha().unwrap(),
        ]);

        let significance = s.test(&()).unwrap().significance_test;
        row_names.push("Significance of Regression".to_string());
        lines.push(vec![
            significance.statistic(),
            significance.probability_value(),
            significance.alpha().unwrap(),
        ]);

        let resid = s.test(&()).unwrap().residual_test;
        row_names.push("Shapiro-Wilk Normal Residual".to_string());
        lines.push(vec![
            resid.statistic(),
            resid.probability_value(),
            resid.alpha().unwrap(),
        ]);

        row_names.push("Null Deviance".to_string());
        lines.push(vec![s.null_deviance, 0.0, 0.0]);

        row_names.push("Residual Deviance".to_string());
        lines.push(vec![s.residual_deviance, 0.0, 0.0]);

        row_names.push("AIC".to_string());
        lines.push(vec![s.aic, 0.0, 0.0]);

        writeln!(f, "{}", DisplayTable::new(headers, row_names, lines, None))?;

        Ok(())
    }
}