4 files changed, 12 insertions, 16 deletions

diff --git a/INSTALL b/INSTALL
index 1a92fa5..b0e1970 100644
--- a/INSTALL
+++ b/INSTALL
@@ -41,7 +41,7 @@ INSTALLATION ON WINDOWS ----------------------------------------
      change to:    build-type:         Simple
 
      line 160:     extra-libraries:
-     add:          extra-libraries: libgls-0 blas lapack
+     add:          extra-libraries: libgsl-0 blas lapack
 
      line 161:     extra-lib-dirs:
      add:          extra-lib-dirs: c:\ghc\ghc-6.10.3\bin
diff --git a/configure.hs b/configure.hs
index 2764dbc..7aa296e 100644
--- a/configure.hs
+++ b/configure.hs
@@ -36,7 +36,7 @@ opts = [ ""                              -- Ubuntu/Debian
        ]
 
 -- compile a simple program with symbols from GSL and LAPACK with the given libs
-testprog libs fmks = "echo \"#include <gsl/gsl_math.h>\nint main(){zgesvd_(); gsl_sf_gamma();}\""
+testprog libs fmks = "echo \"#include <gsl/gsl_sf_gamma.h>\nint main(){zgesvd_(); gsl_sf_gamma(5);}\""
                      ++" > /tmp/dummy.c; gcc /tmp/dummy.c -o /tmp/dummy "
                      ++ f1 libs ++ " " ++ f2 fmks ++ " > /dev/null 2> /dev/null"
 
@@ -46,7 +46,7 @@ f2 = unwords . map ("-framework "++) . words
 check libs fmks = (ExitSuccess ==) `fmap` system (testprog libs fmks)
 
 -- simple test for GSL
-testGSL = "echo \"#include <gsl/gsl_math.h>\nint main(){gsl_sf_gamma();}\""
+testGSL = "echo \"#include <gsl/gsl_sf_gamma.h>\nint main(){gsl_sf_gamma(5);}\""
            ++" > /tmp/dummy.c; gcc /tmp/dummy.c -o /tmp/dummy -lgsl -lgslcblas"
            ++ " > /dev/null 2> /dev/null"
 
diff --git a/examples/root.hs b/examples/root.hs
index 9a674fd..69db243 100644
--- a/examples/root.hs
+++ b/examples/root.hs
@@ -1,27 +1,17 @@
 -- root finding examples
 import Numeric.GSL
 import Numeric.LinearAlgebra
-import Graphics.Plot
 import Text.Printf(printf)
 
 rosenbrock a b [x,y] = [ a*(1-x), b*(y-x^2) ]
 
-disp = putStrLn . format "  " (printf "%.3f")
-
--- Numerical estimation of the gradient
-gradient f v = [partialDerivative k f v | k <- [0 .. length v -1]]
-
-partialDerivative n f v = fst (derivCentral 0.01 g (v!!n)) where
-    g x = f (concat [a,x:b])
-    (a,_:b) = splitAt n v
-
 test method = do
     print method
     let (s,p) = root method 1E-7 30 (rosenbrock 1 10) [-10,-5]
     print s -- solution
     disp p -- evolution of the algorithm
---    let [x,y] = tail (toColumns p)
---    mplot [x,y]  -- path from the starting point to the solution
+
+disp = putStrLn . format "  " (printf "%.3f")
 
 main = do
     test Hybrids
diff --git a/lib/Numeric/GSL/Root.hs b/lib/Numeric/GSL/Root.hs
index ad1b72c..d674fad 100644
--- a/lib/Numeric/GSL/Root.hs
+++ b/lib/Numeric/GSL/Root.hs
@@ -76,7 +76,7 @@ root method epsabs maxit fun xinit = rootGen (fi (fromEnum method)) fun xinit ep
 rootGen m f xi epsabs maxit = unsafePerformIO $ do
     let xiv = fromList xi
         n   = dim xiv
-    fp <- mkVecVecfun (aux_vTov (fromList.f.toList))
+    fp <- mkVecVecfun (aux_vTov (fromList . checkdim n f . toList))
     rawpath <- withVector xiv $ \xiv' ->
                    createMIO maxit (2*n+1)
                          (c_root m fp epsabs (fi maxit) // xiv')
@@ -115,3 +115,9 @@ createMIO r c fun msg = do
     res <- createMatrix RowMajor r c
     app1 fun mat res msg
     return res
+
+checkdim n f x
+    | length y /= n = error $ "Error: "++ show n
+                              ++ " results expected in the function supplied to root"
+    | otherwise = y
+  where y = f x