commit 9496db0255d743fe978a744c59b53929689f3edb
Author: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date:   Thu Oct 19 18:42:05 2023 +0200

    Iterators

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..ae869a8
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "submatrix"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..128fd24
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "submatrix"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..c8ff5f8
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,41 @@
+mod matrix;
+use matrix::Matrix;
+    
+fn main() {
+    let mut mat = Matrix::<_>::new(4,3, 0.0f64);
+    println!("nrows : {}", mat.nrows());
+    println!("ncols : {}", mat.ncols());
+    let mut k=0;
+    for x in mat.iter_1d_col_mut() {
+        *x = k as f64;
+        k += 1;
+    }
+
+    println!("{:#?}", mat);
+    for i in mat.iter_1d_col() {
+        print!("{} ", *i);
+    }
+    println!("");
+
+    println!("");
+    for r in 0..mat.nrows() {
+        for i in mat.iter_row(r) {
+            print!("{} ", *i);
+        }
+        println!("");
+    }
+
+    println!("");
+    for r in 0..mat.ncols() {
+        for i in mat.iter_col(r) {
+            print!("{} ", *i);
+        }
+        println!("");
+    }
+    println!("");
+
+    for i in mat.iter_1d_row() {
+        print!("{} ", *i);
+    }
+    println!("");
+}
diff --git a/src/matrix.rs b/src/matrix.rs
new file mode 100644
index 0000000..f85274d
--- /dev/null
+++ b/src/matrix.rs
@@ -0,0 +1,259 @@
+#[derive(Debug)]
+pub struct Matrix<T> {
+    nrows: usize,
+    ncols: usize,
+    data: Vec<T>,
+}
+
+
+impl<T> Matrix<T>
+where
+    T: Clone,
+{
+
+    pub fn new(nrows:usize, ncols:usize, init:T) -> Self {
+        Matrix {
+            nrows, ncols,
+            data: vec![ init ; nrows*ncols ]
+        }
+    }
+
+    pub fn nrows(&self) -> usize {
+        self.nrows
+    }
+
+    pub fn ncols(&self) -> usize {
+        self.ncols
+    }
+
+    pub fn as_slice(&self) -> &[T] {
+        self.data.as_slice()
+    }
+
+    pub fn as_mut_slice(&mut self) -> &mut [T] {
+        self.data.as_mut_slice()
+    }
+
+}
+
+
+// One-dimensional iterators
+
+pub struct MatrixIter1DCol<'a, T> {
+    iter: std::slice::Iter<'a, T>,
+}
+
+impl<'a, T> Iterator for MatrixIter1DCol<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+
+pub struct MatrixIter1DColMut<'a, T> {
+    iter: std::slice::IterMut<'a, T>,
+}
+
+
+impl<'a, T> Iterator for MatrixIter1DColMut<'a, T> {
+    type Item = &'a mut T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+impl<T> Matrix<T> {
+    pub fn iter_1d_col(&self) -> MatrixIter1DCol<'_, T> {
+        MatrixIter1DCol {
+            iter: self.data.iter(),
+        }
+    }
+
+    pub fn iter_1d_col_mut(&mut self) -> MatrixIter1DColMut<'_, T> {
+        MatrixIter1DColMut {
+            iter: self.data.iter_mut(),
+        }
+    }
+}
+
+
+
+// Row iterators
+
+pub struct MatrixIterRow<'a, T> {
+    iter: std::iter::StepBy<std::slice::Iter<'a, T>>,
+}
+
+impl<'a, T> Iterator for MatrixIterRow<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+
+pub struct MatrixIterRowMut<'a, T> {
+    iter: std::iter::StepBy<std::slice::IterMut<'a, T>>,
+}
+
+
+impl<'a, T> Iterator for MatrixIterRowMut<'a, T> {
+    type Item = &'a mut T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+
+impl<T> Matrix<T> {
+    pub fn iter_row(&self, row: usize) -> MatrixIterRow<'_, T> {
+        MatrixIterRow {
+            iter: self.data[row..].iter().step_by(self.nrows),
+        }
+    }
+
+    pub fn iter_row_mut(&mut self, row: usize) -> MatrixIterRowMut<'_, T> {
+        MatrixIterRowMut {
+            iter: self.data[row..].iter_mut().step_by(self.nrows),
+        }
+    }
+}
+
+
+// Column iterators
+
+pub struct MatrixIterCol<'a, T> {
+    iter: std::slice::Iter<'a, T>,
+}
+
+impl<'a, T> Iterator for MatrixIterCol<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+
+pub struct MatrixIterColMut<'a, T> {
+    iter: std::slice::IterMut<'a, T>,
+}
+
+
+impl<'a, T> Iterator for MatrixIterColMut<'a, T> {
+    type Item = &'a mut T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+
+impl<T> Matrix<T> {
+    pub fn iter_col(&self, col: usize) -> MatrixIterCol<'_, T> {
+        let nrows = self.nrows;
+        let start = col*nrows;
+        let end = start+nrows;
+        MatrixIterCol {
+            iter: self.data[start..end].iter(),
+        }
+    }
+
+    pub fn iter_col_mut(&mut self, col: usize) -> MatrixIterColMut<'_, T> {
+        let nrows = self.nrows;
+        let start = col*nrows;
+        let end = start+nrows;
+        MatrixIterColMut {
+            iter: self.data[start..end].iter_mut(),
+        }
+    }
+}
+
+
+
+// One-dimensional iterator by row
+
+pub struct MatrixIter1DRow<'a, T> {
+    mat: &'a Matrix<T>,
+    iter: MatrixIterRow<'a, T>,
+    row: std::ops::Range <usize>,
+}
+
+impl<'a, T> Iterator for MatrixIter1DRow<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let v = self.iter.next();
+        match v {
+            Some(_) => v,
+            None => {
+                let new_row = self.row.next();
+                match new_row {
+                    None => None,
+                    Some(i) => {
+                        self.iter = self.mat.iter_row(i);
+                        self.iter.next()
+                    }
+                }
+            }
+        }
+    }
+}
+
+pub struct MatrixIter1DRowMut<'a, T> {
+    mat: &'a mut Matrix<T>,
+    iter: MatrixIterRowMut<'a, T>,
+    row: std::ops::Range <usize>,
+}
+
+
+/*
+impl<'a, T> Iterator for MatrixIter1DRowMut<'a, T> {
+    type Item = &'a mut T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let v = self.iter.next();
+        match v {
+            Some(_) => v,
+            None => {
+                let new_row = self.row.next();
+                match new_row {
+                    None => None,
+                    Some(i) => {
+                        self.iter = self.mat.iter_row_mut(i);
+                        self.iter.next()
+                    }
+                }
+            }
+        }
+    }
+}
+*/
+
+impl<T> Matrix<T> {
+    pub fn iter_1d_row(&self) -> MatrixIter1DRow<'_, T> {
+        MatrixIter1DRow {
+            mat: self,
+            iter: self.iter_row(0),
+            row: 1..self.nrows,
+        }
+    }
+
+    /*
+    pub fn iter_1d_row_mut(&mut self) -> MatrixIter1DRowMut<'_, T> {
+        MatrixIter1DRowMut {
+            mat: self,
+            iter: self.iter_row_mut(0),
+            row: 1..self.nrows,
+        }
+    }
+    */
+}
+
+
+