Merge pull request #27 from LaurentMazare/layout-refactor

Refactor the stride/shape handling

1 files changed, 16 insertions, 9 deletions

diff --git a/candle-core/src/strided_index.rs b/candle-core/src/strided_index.rs
index 2a23e9ec..e6d2868b 100644
--- a/candle-core/src/strided_index.rs
+++ b/candle-core/src/strided_index.rs
@@ -1,27 +1,28 @@
+use crate::Layout;
+
 /// An iterator over offset position for items of an N-dimensional arrays stored in a
 /// flat buffer using some potential strides.
 #[derive(Debug)]
 pub(crate) struct StridedIndex<'a> {
     next_storage_index: Option<usize>,
     multi_index: Vec<usize>,
-    dims: &'a [usize],
-    stride: &'a [usize],
+    layout: &'a Layout,
 }
 
 impl<'a> StridedIndex<'a> {
-    pub(crate) fn new(dims: &'a [usize], stride: &'a [usize]) -> Self {
+    pub(crate) fn new(layout: &'a Layout) -> Self {
+        let dims = layout.dims();
         let elem_count: usize = dims.iter().product();
         let next_storage_index = if elem_count == 0 {
             None
         } else {
             // This applies to the scalar case.
-            Some(0)
+            Some(layout.start_offset())
         };
         StridedIndex {
             next_storage_index,
             multi_index: vec![0; dims.len()],
-            dims,
-            stride,
+            layout,
         }
     }
 }
@@ -35,7 +36,12 @@ impl<'a> Iterator for StridedIndex<'a> {
             Some(storage_index) => storage_index,
         };
         let mut updated = false;
-        for (multi_i, max_i) in self.multi_index.iter_mut().zip(self.dims.iter()).rev() {
+        for (multi_i, max_i) in self
+            .multi_index
+            .iter_mut()
+            .zip(self.layout.dims().iter())
+            .rev()
+        {
             let next_i = *multi_i + 1;
             if next_i < *max_i {
                 *multi_i = next_i;
@@ -49,9 +55,10 @@ impl<'a> Iterator for StridedIndex<'a> {
             let next_storage_index = self
                 .multi_index
                 .iter()
-                .zip(self.stride.iter())
+                .zip(self.layout.stride().iter())
                 .map(|(&x, &y)| x * y)
-                .sum();
+                .sum::<usize>()
+                + self.layout.start_offset();
             Some(next_storage_index)
         } else {
             None