Add QR implementation (without slice drop)

Author: termoshtt

src/impl2/mod.rs

@@ -4,5 +4,5 @@ pub mod qr;
 pub use self::opnorm::*;
 pub use self::qr::*;
 
-pub trait LapackScalar: OperatorNorm_ {}
-impl<A> LapackScalar for A where A: OperatorNorm_ {}
+pub trait LapackScalar: OperatorNorm_ + QR_ {}
+impl<A> LapackScalar for A where A: OperatorNorm_ + QR_ {}

src/layout.rs

@@ -44,6 +44,10 @@ pub trait AllocatedArray {
     fn as_allocated(&self) -> Result<&[Self::Scalar]>;
 }
 
+pub trait AllocatedArrayMut: AllocatedArray {
+    fn as_allocated_mut(&mut self) -> Result<&mut [Self::Scalar]>;
+}
+
 impl<A, S> AllocatedArray for ArrayBase<S, Ix2>
     where S: Data<Elem = A>
 {
@@ -76,3 +80,21 @@ impl<A, S> AllocatedArray for ArrayBase<S, Ix2>
         Ok(slice)
     }
 }
+
+impl<A, S> AllocatedArrayMut for ArrayBase<S, Ix2>
+    where S: DataMut<Elem = A>
+{
+    fn as_allocated_mut(&mut self) -> Result<&mut [A]> {
+        let slice = self.as_slice_memory_order_mut().ok_or(MemoryContError::new())?;
+        Ok(slice)
+    }
+}
+
+pub fn reconstruct<A, S>(l: Layout, a: Vec<A>) -> Result<ArrayBase<S, Ix2>>
+    where S: DataOwned<Elem = A>
+{
+    Ok(match l {
+        Layout::C((row, col)) => ArrayBase::from_shape_vec((row as usize, col as usize), a)?,
+        Layout::F((col, row)) => ArrayBase::from_shape_vec((row as usize, col as usize).f(), a)?,
+    })
+}

src/traits.rs

@@ -34,3 +34,19 @@ impl<A, S> OperationNorm for ArrayBase<S, Ix2>
         Ok(A::opnorm(t, l, a))
     }
 }
+
+pub trait QR<Q, R> {
+    fn qr(self) -> Result<(Q, R)>;
+}
+
+impl<A, Sq, Sr> QR<ArrayBase<Sq, Ix2>, ArrayBase<Sr, Ix2>> for ArrayBase<Sq, Ix2>
+    where A: LapackScalar,
+          Sq: DataMut<Elem = A>,
+          Sr: DataOwned<Elem = A>
+{
+    fn qr(mut self) -> Result<(ArrayBase<Sq, Ix2>, ArrayBase<Sr, Ix2>)> {
+        let l = self.layout()?;
+        let r = A::qr(l, self.as_allocated_mut()?)?;
+        Ok((self, reconstruct(l, r)?))
+    }
+}