more defined fromRows/fromColumns/fromBlocks

2 files changed, 15 insertions, 4 deletions

diff --git a/lib/Data/Packed/Internal/Common.hs b/lib/Data/Packed/Internal/Common.hs
index 629016d..972cd7d 100644
--- a/lib/Data/Packed/Internal/Common.hs
+++ b/lib/Data/Packed/Internal/Common.hs
@@ -18,7 +18,7 @@ module Data.Packed.Internal.Common(
   Adapt,
   app1, app2, app3, app4,
   (//), check,
-  partit, common,
+  partit, common, compatdim,
   fi
 ) where
 
@@ -41,6 +41,12 @@ common f = commonval . map f where
     commonval [a] = Just a
     commonval (a:b:xs) = if a==b then commonval (b:xs) else Nothing
 
+-- | common value with \"adaptable\" 1
+compatdim :: [Int] -> Maybe Int
+compatdim [] = Nothing
+compatdim [a] = Just a
+compatdim (a:b:xs) = if a==b || a==1 || b==1 then compatdim (max a b:xs) else Nothing
+
 -- | postfix function application (@flip ($)@)
 (//) :: x -> (x -> y) -> y
 infixl 0 //
diff --git a/lib/Data/Packed/Internal/Matrix.hs b/lib/Data/Packed/Internal/Matrix.hs
index a220f1a..33c9324 100644
--- a/lib/Data/Packed/Internal/Matrix.hs
+++ b/lib/Data/Packed/Internal/Matrix.hs
@@ -135,11 +135,16 @@ type Mt t s = Int -> Int -> Ptr t -> s
 toLists :: (Element t) => Matrix t -> [[t]]
 toLists m = partit (cols m) . toList . flatten $ m
 
--- | creates a Matrix from a list of vectors
+-- | Create a matrix from a list of vectors.
+-- All vectors must have the same dimension,
+-- or dimension 1, which is are automatically expanded.
 fromRows :: Element t => [Vector t] -> Matrix t
-fromRows vs = case common dim vs of
+fromRows vs = case compatdim (map dim vs) of
     Nothing -> error "fromRows applied to [] or to vectors with different sizes"
-    Just c  -> reshape c (join vs)
+    Just c  -> reshape c . join . map (adapt c) $ vs
+  where
+    adapt c v | dim v == c = v
+              | otherwise = constantD (v@>0) c
 
 -- | extracts the rows of a matrix as a list of vectors
 toRows :: Element t => Matrix t -> [Vector t]