add examples

1 files changed, 26 insertions, 0 deletions

diff --git a/examples/pinv2.hs b/examples/pinv2.hs
new file mode 100644
index 0000000..c1038d1
--- /dev/null
+++ b/examples/pinv2.hs
@@ -0,0 +1,26 @@
+-- MSE polynomial model using the pseudoinverse
+import LinearAlgebra
+import Graphics.Plot
+
+expand :: Int -> Vector Double -> Matrix Double
+expand n x = fromColumns $ constant 1 (dim x): map (x^) [1 .. n]
+
+polynomialModel :: Matrix Double -> Int -> (Vector Double -> Vector Double)
+polynomialModel d n = f where
+    f z = expand n z <> ws 
+    ws  = pinv a <> b
+    [x,b] = toColumns d 
+    a = expand n x
+
+mk fv = f where
+    f x = fv (fromList [x]) @> 0
+
+main = do
+    d <- readMatrix `fmap` readFile "data.txt"
+    let [x,y] = toColumns d
+    let pol = polynomialModel d
+    let view = [x, y, pol 1 x, pol 2 x, pol 3 x]
+    dispR 2 $ fromColumns view
+    mplot view
+    let f = mk (pol 2)
+    print (f 2.5)