From 1925c123d7d8184a1d2ddc0a413e0fd2776e1083 Mon Sep 17 00:00:00 2001
From: Alberto Ruiz <aruiz@um.es>
Date: Thu, 8 May 2014 08:48:12 +0200
Subject: empty hmatrix-base

---
 examples/pca2.hs | 65 --------------------------------------------------------
 1 file changed, 65 deletions(-)
 delete mode 100644 examples/pca2.hs

(limited to 'examples/pca2.hs')

diff --git a/examples/pca2.hs b/examples/pca2.hs
deleted file mode 100644
index e7ea95f..0000000
--- a/examples/pca2.hs
+++ /dev/null
@@ -1,65 +0,0 @@
--- Improved PCA, including illustrative graphics
-
-import Numeric.LinearAlgebra
-import Graphics.Plot
-import System.Directory(doesFileExist)
-import System.Process(system)
-import Control.Monad(when)
-
-type Vec = Vector Double
-type Mat = Matrix Double
-
--- Vector with the mean value of the columns of a matrix
-mean a = constant (recip . fromIntegral . rows $ a) (rows a) <> a
-
--- covariance matrix of a list of observations stored as rows
-cov x = (trans xc <> xc) / fromIntegral (rows x - 1)
-    where xc = x - asRow (mean x)
-
-
-type Stat = (Vec, [Double], Mat)
--- 1st and 2nd order statistics of a dataset (mean, eigenvalues and eigenvectors of cov)
-stat :: Mat -> Stat
-stat x = (m, toList s, trans v) where
-    m = mean x
-    (s,v) = eigSH' (cov x)
-
--- creates the compression and decompression functions from the desired reconstruction
--- quality and the statistics of a data set
-pca :: Double -> Stat -> (Vec -> Vec , Vec -> Vec)
-pca prec (m,s,v) = (encode,decode)    
-  where    
-    encode x = vp <> (x - m)
-    decode x = x <> vp + m
-    vp = takeRows n v
-    n = 1 + (length $ fst $ span (< (prec'*sum s)) $ cumSum s)
-    cumSum = tail . scanl (+) 0.0
-    prec' = if prec <=0.0 || prec >= 1.0
-                then error "the precision in pca must be 0<prec<1"
-                else prec
-
-shdigit :: Vec -> IO ()
-shdigit v = imshow (reshape 28 (-v))
-
--- shows the effect of a given reconstruction quality on a test vector
-test :: Stat -> Double -> Vec -> IO ()
-test st prec x = do
-    let (pe,pd) = pca prec st
-    let y = pe x
-    print $ dim y
-    shdigit (pd y)
-
-main = do
-    ok <- doesFileExist ("mnist.txt")
-    when (not ok)  $ do
-        putStrLn "\nTrying to download test datafile..."
-        system("wget -nv http://dis.um.es/~alberto/material/sp/mnist.txt.gz")
-        system("gunzip mnist.txt.gz")
-        return ()
-    m <- loadMatrix "mnist.txt"
-    let xs = takeColumns (cols m -1) m
-    let x = toRows xs !! 4  -- an arbitrary test vector
-    shdigit x
-    let st = stat xs
-    test st 0.90 x
-    test st 0.50 x
-- 
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