diff --git a/Cargo.toml b/Cargo.toml
index aa9db4a..e98959a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sitk-registration-sys"
-version = "2025.3.1"
+version = "2025.3.2"
 edition = "2024"
 license = "MIT OR Apache-2.0"
 description = "register and interpolate images"
@@ -14,11 +14,11 @@ keywords = ["registration", "affine", "bspline", "transform"]
 categories = ["multimedia::images", "science"]
 
 [lib]
-name = "sitk_regsitration_sys"
+name = "sitk_registration_sys"
 crate-type = ["cdylib", "rlib"]
 
 [dependencies]
-anyhow = "1.0.96"
+anyhow = "1.0.97"
 libc = "0.2.170"
 ndarray = "0.16.1"
 num = "0.4.3"
@@ -28,4 +28,7 @@ serde_yaml = "0.9.33"
 
 [build-dependencies]
 cmake = "0.1.54"
-git2 = "0.20.0"
\ No newline at end of file
+git2 = "0.20.0"
+
+[dev-dependencies]
+tempfile = "3.18.0"
\ No newline at end of file
diff --git a/cpp/sitk_adapter.cxx b/cpp/sitk_adapter.cxx
index 52e9a85..b65d997 100644
--- a/cpp/sitk_adapter.cxx
+++ b/cpp/sitk_adapter.cxx
@@ -286,8 +286,8 @@ reg(
     try {
         string kind = (t_or_a == false) ? "translation" : "affine";
 //         std::filesystem::path output_path = std::filesystem::temp_directory_path() / gen_random(12);
-        std::filesystem::path output_path = std::filesystem::temp_directory_path();
 //         std::filesystem::create_directory(output_path);
+        std::filesystem::path output_path = std::filesystem::temp_directory_path();
 
         sitk::ElastixImageFilter tfilter = sitk::ElastixImageFilter();
         tfilter.LogToConsoleOff();
@@ -298,11 +298,7 @@ reg(
         tfilter.SetParameterMap(sitk::GetDefaultParameterMap(kind));
         tfilter.SetParameter("WriteResultImage", "false");
         tfilter.SetOutputDirectory(output_path);
-//         cout << "output_path: " << output_path << endl;
-    //     tfilter.PrintParameterMap();
-//         cout << "r6 " << std::flush;
         tfilter.Execute();
-//         cout << "r7 " << std::flush;
         sitk::ElastixImageFilter::ParameterMapType parameter_map = tfilter.GetTransformParameterMap(0);
         for (sitk::ElastixImageFilter::ParameterMapType::iterator parameter = parameter_map.begin(); parameter != parameter_map.end(); ++parameter) {
             if (parameter->first == "TransformParameters") {
@@ -323,7 +319,6 @@ reg(
           break;
           }
         }
-//         cout << "r8 " << std::flush;
     } catch (const std::exception &exc) {
         cerr << exc.what();
     }
@@ -334,14 +329,14 @@ extern "C" void
 register_u8(
   unsigned int width,
   unsigned int height,
-  uint8_t* fixed_arr,
-  uint8_t* moving_arr,
+  uint8_t** fixed_arr,
+  uint8_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkUInt8;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -349,14 +344,14 @@ extern "C" void
 register_i8(
   unsigned int width,
   unsigned int height,
-  int8_t* fixed_arr,
-  int8_t* moving_arr,
+  int8_t** fixed_arr,
+  int8_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkInt8;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -364,14 +359,14 @@ extern "C" void
 register_u16(
   unsigned int width,
   unsigned int height,
-  uint16_t* fixed_arr,
-  uint16_t* moving_arr,
+  uint16_t** fixed_arr,
+  uint16_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkUInt16;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -379,14 +374,14 @@ extern "C" void
 register_i16(
   unsigned int width,
   unsigned int height,
-  int16_t* fixed_arr,
-  int16_t* moving_arr,
+  int16_t** fixed_arr,
+  int16_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkInt16;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -394,14 +389,14 @@ extern "C" void
 register_u32(
   unsigned int width,
   unsigned int height,
-  uint32_t* fixed_arr,
-  uint32_t* moving_arr,
+  uint32_t** fixed_arr,
+  uint32_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkUInt32;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -409,14 +404,14 @@ extern "C" void
 register_i32(
   unsigned int width,
   unsigned int height,
-  int32_t* fixed_arr,
-  int32_t* moving_arr,
+  int32_t** fixed_arr,
+  int32_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkInt32;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -424,14 +419,14 @@ extern "C" void
 register_u64(
   unsigned int width,
   unsigned int height,
-  uint64_t* fixed_arr,
-  uint64_t* moving_arr,
+  uint64_t** fixed_arr,
+  uint64_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkUInt64;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -439,14 +434,14 @@ extern "C" void
 register_i64(
   unsigned int width,
   unsigned int height,
-  int64_t* fixed_arr,
-  int64_t* moving_arr,
+  int64_t** fixed_arr,
+  int64_t** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkInt64;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -454,14 +449,14 @@ extern "C" void
 register_f32(
   unsigned int width,
   unsigned int height,
-  float* fixed_arr,
-  float* moving_arr,
+  float** fixed_arr,
+  float** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkFloat32;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
 
@@ -469,13 +464,13 @@ extern "C" void
 register_f64(
   unsigned int width,
   unsigned int height,
-  double* fixed_arr,
-  double* moving_arr,
+  double** fixed_arr,
+  double** moving_arr,
   bool t_or_a,
   double** transform
 ) {
   sitk::PixelIDValueEnum id = sitk::PixelIDValueEnum::sitkFloat64;
-  sitk::Image fixed = make_image(width, height, fixed_arr, id);
-  sitk::Image moving = make_image(width, height, moving_arr, id);
+  sitk::Image fixed = make_image(width, height, *fixed_arr, id);
+  sitk::Image moving = make_image(width, height, *moving_arr, id);
   reg(fixed, moving, t_or_a, transform);
 }
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index d813138..057a7e7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,14 +1,52 @@
 mod sys;
 
-use crate::sys::{PixelType, interp, register};
+use crate::sys::{interp, register};
 use anyhow::{Result, anyhow};
-use ndarray::{Array2, ArrayView2, array, s};
+use ndarray::{Array2, ArrayView2, AsArray, Ix2, array, s};
 use serde::{Deserialize, Serialize};
 use serde_yaml::{from_reader, to_writer};
 use std::fs::File;
 use std::ops::Mul;
 use std::path::PathBuf;
 
+/// a trait marking number types that can be used in sitk:
+/// (u/i)(8/16/32/64), (u/i)size, f(32/64)
+pub trait PixelType: Clone {
+    const PT: u8;
+}
+
+macro_rules! sitk_impl {
+    ($($T:ty: $sitk:expr $(,)?)*) => {
+        $(
+            impl PixelType for $T {
+                const PT: u8 = $sitk;
+            }
+        )*
+    };
+}
+
+sitk_impl! {
+    u8: 1,
+    i8: 2,
+    u16: 3,
+    i16: 4,
+    u32: 5,
+    i32: 6,
+    u64: 7,
+    i64: 8,
+    f32: 9,
+    f64: 10,
+}
+
+#[cfg(target_pointer_width = "64")]
+sitk_impl!(usize: 7);
+#[cfg(target_pointer_width = "32")]
+sitk_impl!(usize: 5);
+#[cfg(target_pointer_width = "64")]
+sitk_impl!(isize: 8);
+#[cfg(target_pointer_width = "32")]
+sitk_impl!(isize: 6);
+
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct Transform {
     pub parameters: [f64; 6],
@@ -47,6 +85,17 @@ impl Mul for Transform {
     }
 }
 
+impl PartialEq<Self> for Transform {
+    fn eq(&self, other: &Self) -> bool {
+        self.parameters == other.parameters
+            && self.dparameters == other.dparameters
+            && self.origin == other.origin
+            && self.shape == other.shape
+    }
+}
+
+impl Eq for Transform {}
+
 impl Transform {
     /// parameters: flat 2x2 part of matrix, translation; origin: center of rotation
     pub fn new(parameters: [f64; 6], origin: [f64; 2], shape: [usize; 2]) -> Self {
@@ -59,10 +108,11 @@ impl Transform {
     }
 
     /// find the affine transform which transforms moving into fixed
-    pub fn register_affine<T: PixelType>(
-        fixed: ArrayView2<T>,
-        moving: ArrayView2<T>,
-    ) -> Result<Transform> {
+    pub fn register_affine<'a, A, T>(fixed: A, moving: A) -> Result<Transform>
+    where
+        T: 'a + PixelType,
+        A: AsArray<'a, T, Ix2>,
+    {
         let (parameters, origin, shape) = register(fixed, moving, true)?;
         Ok(Transform {
             parameters,
@@ -73,10 +123,11 @@ impl Transform {
     }
 
     /// find the translation which transforms moving into fixed
-    pub fn register_translation<T: PixelType>(
-        fixed: ArrayView2<T>,
-        moving: ArrayView2<T>,
-    ) -> Result<Transform> {
+    pub fn register_translation<'a, A, T>(fixed: A, moving: A) -> Result<Transform>
+    where
+        T: 'a + PixelType,
+        A: AsArray<'a, T, Ix2>,
+    {
         let (parameters, origin, shape) = register(fixed, moving, false)?;
         Ok(Transform {
             parameters,
@@ -104,7 +155,11 @@ impl Transform {
 
     /// write a transform to a file
     pub fn to_file(&self, path: PathBuf) -> Result<()> {
-        let mut file = File::open(path)?;
+        let mut file = std::fs::OpenOptions::new()
+            .create(true)
+            .write(true)
+            .truncate(true)
+            .open(path)?;
         to_writer(&mut file, self)?;
         Ok(())
     }
@@ -115,23 +170,30 @@ impl Transform {
     }
 
     /// transform an image using nearest neighbor interpolation
-    pub fn transform_image_bspline<T: PixelType>(&self, image: ArrayView2<T>) -> Result<Array2<T>> {
+    pub fn transform_image_bspline<'a, A, T>(&self, image: A) -> Result<Array2<T>>
+    where
+        T: 'a + PixelType,
+        A: AsArray<'a, T, Ix2>,
+    {
         interp(self.parameters, self.origin, image, false)
     }
 
     /// transform an image using bspline interpolation
-    pub fn transform_image_nearest_neighbor<T: PixelType>(
-        &self,
-        image: ArrayView2<T>,
-    ) -> Result<Array2<T>> {
+    pub fn transform_image_nearest_neighbor<'a, A, T>(&self, image: A) -> Result<Array2<T>>
+    where
+        T: 'a + PixelType,
+        A: AsArray<'a, T, Ix2>,
+    {
         interp(self.parameters, self.origin, image, true)
     }
 
     /// get coordinates resulting from transforming input coordinates
-    pub fn transform_coordinates<T>(&self, coordinates: ArrayView2<T>) -> Result<Array2<f64>>
+    pub fn transform_coordinates<'a, A, T>(&self, coordinates: A) -> Result<Array2<f64>>
     where
-        T: Clone + Into<f64>,
+        T: 'a + Clone + Into<f64>,
+        A: AsArray<'a, T, Ix2>,
     {
+        let coordinates = coordinates.into();
         let s = coordinates.shape();
         if s[1] != 2 {
             return Err(anyhow!("coordinates must have two columns"));
@@ -233,6 +295,7 @@ mod tests {
     use anyhow::Result;
     use ndarray::Array2;
     use num::Complex;
+    use tempfile::NamedTempFile;
 
     /// An example of generating julia fractals.
     fn julia_image(shift_x: f32, shift_y: f32) -> Result<Array2<u8>> {
@@ -263,25 +326,35 @@ mod tests {
         Ok(im)
     }
 
+    #[test]
+    fn test_serialization() -> Result<()> {
+        let file = NamedTempFile::new()?;
+        let t = Transform::new([1.2, 0.3, -0.4, 0.9, 10.2, -9.5], [59.5, 49.5], [120, 100]);
+        t.to_file(file.path().to_path_buf())?;
+        let s = Transform::from_file(file.path().to_path_buf())?;
+        assert_eq!(s, t);
+        Ok(())
+    }
+
     macro_rules! interp_tests_bspline {
         ($($name:ident: $t:ty $(,)?)*) => {
-        $(
-            #[test]
-            fn $name() -> Result<()> {
-                let j = julia_image(-120f32, 10f32)?.mapv(|x| x as $t);
-                let k = julia_image(0f32, 0f32)?.mapv(|x| x as $t);
-                let shape = j.shape();
-                let origin = [
-                    ((shape[1] - 1) as f64) / 2f64,
-                    ((shape[0] - 1) as f64) / 2f64,
-                ];
-                let transform = Transform::new([1., 0., 0., 1., 120., -10.], origin, [shape[0], shape[1]]);
-                let n = transform.transform_image_bspline(j.view())?;
-                let d = (k.mapv(|x| x as f64) - n.mapv(|x| x as f64)).powi(2).sum();
-                assert!(d <= (shape[0] * shape[1]) as f64);
-                Ok(())
-            }
-        )*
+            $(
+                #[test]
+                fn $name() -> Result<()> {
+                    let j = julia_image(-120f32, 10f32)?.mapv(|x| x as $t);
+                    let k = julia_image(0f32, 0f32)?.mapv(|x| x as $t);
+                    let shape = j.shape();
+                    let origin = [
+                        ((shape[1] - 1) as f64) / 2f64,
+                        ((shape[0] - 1) as f64) / 2f64,
+                    ];
+                    let transform = Transform::new([1., 0., 0., 1., 120., -10.], origin, [shape[0], shape[1]]);
+                    let n = transform.transform_image_bspline(j.view())?;
+                    let d = (k.mapv(|x| x as f64) - n.mapv(|x| x as f64)).powi(2).sum();
+                    assert!(d <= (shape[0] * shape[1]) as f64);
+                    Ok(())
+                }
+            )*
         }
     }
 
@@ -300,23 +373,28 @@ mod tests {
 
     macro_rules! interp_tests_nearest_neighbor {
         ($($name:ident: $t:ty $(,)?)*) => {
-        $(
-            #[test]
-            fn $name() -> Result<()> {
-                let j = julia_image(-120f32, 10f32)?.mapv(|x| x as $t);
-                let k = julia_image(0f32, 0f32)?.mapv(|x| x as $t);
-                let shape = j.shape();
-                let origin = [
-                    ((shape[1] - 1) as f64) / 2f64,
-                    ((shape[0] - 1) as f64) / 2f64,
-                ];
-                let transform = Transform::new([1., 0., 0., 1., 120., -10.], origin, [shape[0], shape[1]]);
-                let n = transform.transform_image_nearest_neighbor(j.view())?;
-                let d = (k.mapv(|x| x as f64) - n.mapv(|x| x as f64)).powi(2).sum();
-                assert!(d <= (shape[0] * shape[1]) as f64);
-                Ok(())
-            }
-        )*
+            $(
+                #[test]
+                fn $name() -> Result<()> {
+                    let j = julia_image(-120f32, 10f32)?.mapv(|x| x as $t);
+                    let k = julia_image(0f32, 0f32)?.mapv(|x| x as $t);
+                    let shape = j.shape();
+                    let origin = [
+                        ((shape[1] - 1) as f64) / 2f64,
+                        ((shape[0] - 1) as f64) / 2f64,
+                    ];
+                    let j0 = j.clone();
+                    let k0 = k.clone();
+                    let transform = Transform::new([1., 0., 0., 1., 120., -10.], origin, [shape[0], shape[1]]);
+                    // make sure j & k weren't mutated
+                    assert!(j.iter().zip(j0.iter()).map(|(a, b)| a == b).all(|x| x));
+                    assert!(k.iter().zip(k0.iter()).map(|(a, b)| a == b).all(|x| x));
+                    let n = transform.transform_image_nearest_neighbor(j.view())?;
+                    let d = (k.mapv(|x| x as f64) - n.mapv(|x| x as f64)).powi(2).sum();
+                    assert!(d <= (shape[0] * shape[1]) as f64);
+                    Ok(())
+                }
+            )*
         }
     }
 
@@ -340,7 +418,12 @@ mod tests {
                 fn $name() -> Result<()> {
                     let j = julia_image(0f32, 0f32)?.mapv(|x| x as $t);
                     let k = julia_image(10f32, 20f32)?.mapv(|x| x as $t);
+                    let j0 = j.clone();
+                    let k0 = k.clone();
                     let t = Transform::register_translation(j.view(), k.view())?;
+                    // make sure j & k weren't mutated
+                    assert!(j.iter().zip(j0.iter()).map(|(a, b)| a == b).all(|x| x));
+                    assert!(k.iter().zip(k0.iter()).map(|(a, b)| a == b).all(|x| x));
                     let mut m = Array2::eye(3);
                     m[[0, 2]] = -10f64;
                     m[[1, 2]] = -20f64;
diff --git a/src/sys.rs b/src/sys.rs
index 7802a5a..ef34bdc 100644
--- a/src/sys.rs
+++ b/src/sys.rs
@@ -1,6 +1,7 @@
+use crate::PixelType;
 use anyhow::Result;
 use libc::{c_double, c_uint};
-use ndarray::{Array2, ArrayView2};
+use ndarray::{Array2, AsArray, Ix2};
 use one_at_a_time_please::one_at_a_time;
 use std::ptr;
 
@@ -62,48 +63,17 @@ unsafe extern "C" {
     }
 }
 
-pub trait PixelType: Clone {
-    const PT: u8;
-}
-
-macro_rules! sitk_impl {
-    ($($T:ty: $sitk:expr $(,)?)*) => {
-        $(
-            impl PixelType for $T {
-                const PT: u8 = $sitk;
-            }
-        )*
-    };
-}
-
-sitk_impl! {
-    u8: 1,
-    i8: 2,
-    u16: 3,
-    i16: 4,
-    u32: 5,
-    i32: 6,
-    u64: 7,
-    i64: 8,
-    f32: 9,
-    f64: 10,
-}
-
-#[cfg(target_pointer_width = "64")]
-sitk_impl!(usize: 7);
-#[cfg(target_pointer_width = "32")]
-sitk_impl!(usize: 5);
-#[cfg(target_pointer_width = "64")]
-sitk_impl!(isize: 8);
-#[cfg(target_pointer_width = "32")]
-sitk_impl!(isize: 6);
-
-pub(crate) fn interp<T: PixelType>(
+pub(crate) fn interp<'a, A, T>(
     parameters: [f64; 6],
     origin: [f64; 2],
-    image: ArrayView2<T>,
+    image: A,
     bspline_or_nn: bool,
-) -> Result<Array2<T>> {
+) -> Result<Array2<T>>
+where
+    T: 'a + PixelType,
+    A: AsArray<'a, T, Ix2>,
+{
+    let image = image.into();
     let shape: Vec<usize> = image.shape().to_vec();
     let width = shape[1] as c_uint;
     let height = shape[0] as c_uint;
@@ -220,16 +190,22 @@ pub(crate) fn interp<T: PixelType>(
 }
 
 #[one_at_a_time]
-pub(crate) fn register<T: PixelType>(
-    fixed: ArrayView2<T>,
-    moving: ArrayView2<T>,
+pub(crate) fn register<'a, A, T>(
+    fixed: A,
+    moving: A,
     translation_or_affine: bool,
-) -> Result<([f64; 6], [f64; 2], [usize; 2])> {
+) -> Result<([f64; 6], [f64; 2], [usize; 2])>
+where
+    T: 'a + PixelType,
+    A: AsArray<'a, T, Ix2>,
+{
+    let fixed = fixed.into();
+    let moving = moving.into();
     let shape: Vec<usize> = fixed.shape().to_vec();
     let width = shape[1] as c_uint;
     let height = shape[0] as c_uint;
-    let fixed: Vec<_> = fixed.into_iter().cloned().collect();
-    let moving: Vec<_> = moving.into_iter().cloned().collect();
+    let fixed: Vec<_> = fixed.into_iter().collect();
+    let moving: Vec<_> = moving.into_iter().collect();
     let fixed_ptr = fixed.as_ptr();
     let moving_ptr = moving.as_ptr();
     let mut transform: Vec<c_double> = vec![0.0; 6];