Add stride check

Author: termoshtt

src/error.rs

@@ -2,6 +2,7 @@
 
 use std::error;
 use std::fmt;
+use ndarray::Ixs;
 
 #[derive(Debug)]
 pub struct LapackError {
@@ -45,11 +46,14 @@ impl error::Error for NotSquareError {
 }
 
 #[derive(Debug)]
-pub struct StrideError {}
+pub struct StrideError {
+    pub s0: Ixs,
+    pub s1: Ixs,
+}
 
 impl fmt::Display for StrideError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "invalid stride")
+        write!(f, "invalid stride: s0={}, s1={}", self.s0, self.s1)
     }
 }
 

src/matrix.rs

@@ -54,6 +54,12 @@ impl<A> Matrix for Array<A, Ix2>
     }
     fn layout(&self) -> Result<Layout, StrideError> {
         let strides = self.strides();
+        if min(strides[0], strides[1]) != 1 {
+            return Err(StrideError {
+                s0: strides[0],
+                s1: strides[1],
+            });;
+        }
         if strides[0] < strides[1] {
             Ok(Layout::ColumnMajor)
         } else {