only one pinv example

1 files changed, 20 insertions, 0 deletions

diff --git a/examples/pinv.hs b/examples/pinv.hs
new file mode 100644
index 0000000..cab8fc6
--- /dev/null
+++ b/examples/pinv.hs
@@ -0,0 +1,20 @@
+import Numeric.LinearAlgebra
+import Graphics.Plot
+import Text.Printf(printf)
+
+expand :: Int -> Vector Double -> Matrix Double
+expand n x = fromColumns $ constant 1 (dim x): map (x^) [1 .. n]
+
+polynomialModel :: Vector Double -> Vector Double -> Int
+                -> (Vector Double -> Vector Double)
+polynomialModel x y n = f where
+    f z = expand n z <> ws
+    ws  = expand n x <\> y
+
+main = do
+    [x,y] <- (toColumns . readMatrix) `fmap` readFile "data.txt"
+    let pol = polynomialModel x y
+    let view = [x, y, pol 1 x, pol 2 x, pol 3 x]
+    putStrLn $ "  x      y      p 1    p 2    p 3"
+    putStrLn $ format "  " (printf "%.2f") $ fromColumns view
+    mplot view