Fix Index conversion turning OOB

sprs/src/sparse/csmat.rs

@@ -1788,6 +1788,11 @@ pub mod raw {
 
         assert!(indptr.iter().all(num_traits::Zero::is_zero));
 
+        assert!(
+            I::try_from_usize(mat.rows()).is_some(),
+            "Index type is not large enough to hold the number of rows requested (I::max_value={:?} vs. required {})", I::max_value(), mat.rows(),
+        );
+
         for vec in mat.outer_iterator() {
             for (inner_dim, _) in vec.iter() {
                 indptr[inner_dim] += Iptr::one();
@@ -1805,10 +1810,11 @@ pub mod raw {
         }
 
         for (outer_dim, vec) in mat.outer_iterator().enumerate() {
+            let outer_dim = I::from_usize_unchecked(outer_dim);
             for (inner_dim, val) in vec.iter() {
                 let dest = indptr[inner_dim].index();
                 data[dest] = val.clone();
-                indices[dest] = I::from_usize_unchecked(outer_dim);
+                indices[dest] = outer_dim;
                 indptr[inner_dim] += Iptr::one();
             }
         }

sprs/tests/gh374.rs

@@ -0,0 +1,33 @@
+use ndarray::Array2;
+use sprs::CsMatI;
+
+type Mat = CsMatI<f32, u16, usize>;
+
+fn dense_nnz(arr: &Array2<f32>) -> usize {
+    arr.iter().map(|&f| usize::from(f != 0.0)).sum()
+}
+
+#[test]
+#[should_panic(expected = "Index type is not large enough to hold")]
+fn main() {
+    // create matrix so that row index doesn't fit into column index type after transposition
+    let mut x_sprs = Mat::zero((1_usize << 18, usize::from(1_u16 << 4)));
+    x_sprs.insert(1_usize << 17, usize::from(1_u16 << 2), 1.0);
+
+    // compute X^T * X in the sparse representation
+    let x_t_sprs = x_sprs.transpose_view();
+    let x_t_x_sprs = &x_t_sprs * &x_sprs;
+
+    // compute X^T * X in the dense representation
+    let x_dense = x_sprs.to_dense();
+    let x_t_x_dense = x_dense.t().dot(&x_dense);
+
+    // convert sparse result to dense representation for comparison
+    let x_t_x_sprs_to_dense = x_t_x_sprs.to_dense();
+
+    assert_eq!(x_sprs.nnz(), 1);
+    assert_eq!(x_t_x_sprs.nnz(), 1);
+    assert_eq!(dense_nnz(&x_dense), 1);
+    assert_eq!(dense_nnz(&x_t_x_dense), 1);
+    assert_eq!(dense_nnz(&x_t_x_sprs_to_dense), 1);
+}