Added missing example file

nalgebra-sparse/example/spmm.rs

@@ -0,0 +1,25 @@
+extern crate nalgebra_sparse;
+use nalgebra_sparse::CsrMatrix;
+use std::time::{Duration, Instant};
+
+#[cfg(feature = "io")]
+use nalgebra_sparse::io::load_coo_from_matrix_market_file;
+fn main() {
+    #[cfg(feature = "io")]
+    {
+        let sparse_input_matrix =
+            load_coo_from_matrix_market_file::<f64, _>("./data/crankseg_1.mtx").unwrap();
+        let sparse_input_matrix = CsrMatrix::from(&sparse_input_matrix);
+        let spmm_result = &sparse_input_matrix * &sparse_input_matrix;
+        let now = Instant::now();
+        let spmm_result = &sparse_input_matrix * &sparse_input_matrix;
+        let spmm_time = now.elapsed().as_millis();
+        println!("SGEMM time was {}", spmm_time);
+        let sum: f64 = spmm_result.triplet_iter().map(|(_, _, v)| v).sum();
+        println!("sum of product is {}", sum);
+    }
+    #[cfg(not(feature = "io"))]
+    {
+        panic!("Run with IO feature only");
+    }
+}