tests/testthat/test_Rautoenc_fit.R

In OUTRIDER: OUTRIDER - OUTlier in RNA-Seq fInDER

context("Autoencoder: ")

if(FALSE){
    set.seed(42)
    
    ## simulation of data
    n = 30 # samples
    p = 20 # genes
    q = 6 # latent space dimension
    s=rnorm(n,mean=1, sd = 0.1)
    theta = 25
    
    h_true <- matrix(rnorm(n*q), nrow=n, ncol=q)
    Wd_true <- matrix(rnorm(p*(q+1)), nrow=p, ncol=q+1)
    y_true <- Wd_true%*%t(cbind(rep(1,n),h_true))
    k <- apply(
        y_true,
        1,
        function(yi)
            rnbinom(n, mu=s*exp(yi), size=theta)
    )
    
    ## check that the simulated counts seem to make sense
    # hist(log10(1+k))
    
    # compute x
    x0 <- log((1+k)/s)
    xbar <- colMeans(x0)
    x <- t(t(x0)-xbar)
    
    # ## value for random weight init
    w <- c(rnorm(p*q, sd=1/p*q), rep(0,p))
    # expect a real positiv number.
    randLoss <- loss(w, k, x, s, xbar, theta)
    
    ## init with pca on centered log counts
    library(pcaMethods)
    x  <- t(t(x0)- xbar)
    pca <- pca(x, nPcs = q) ## could also use ppca
    pc  <- loadings(pca)
    w_guess <- as.vector(pc)
    ## indeed much better guess
    pcaLoss <- loss(c(w_guess, rep(0,p)), k, x, s, xbar, theta)
    
    ## init with pca on centered log counts
    ## we'd need the gradient for this one to go fast
    ## It might be a good idea to restrict to Wd = t(We).
    ## I feel this is too much over-fitted otherwise
    
    fit <- optim(c(w_guess, rep(0,p)), loss, k=k, s=s, x=x, xbar=xbar, theta=theta, 
            method="L-BFGS-B", control = list(maxit=300))
    fitLoss <- loss(fit$par, k, x, s, xbar, theta)
    fit2 <- optim(c(w_guess, rep(0,p)), loss, gr = lossGrad, k=k, x=x, s=s, 
            xbar=xbar, theta=25, method="L-BFGS-B", control = list(maxit=300))
    fitGradLoss <- loss(fit2$par, k, x, s, xbar, theta)
    
    test_that("Dimensions match.", {
        expect_equal(length(w_guess), p*q)
        expect_equal(length(fit$par), p*(q+1))
        expect_equal(length(lossGrad(fit$par, k, x, s, xbar, theta)), p*(q+1))
    })
    
    test_that("Losses match (fitLoss ~= fitGradLoss)",{
        expect_equal(fitLoss, fitGradLoss, tol=0.1)
    })
    
    test_that("randLoss > pcaLoss > fitGradLoss",{ 
        expect(randLoss >= pcaLoss)
        expect(pcaLoss >= fitGradLoss)
    })
}