add Result to csolve output

src/splines/spline_f64.rs

@@ -3,6 +3,8 @@ use ndarray::{Array1, Array2};
 use num_traits::{Signed, Zero};
 use std::iter::Sum;
 use std::ops::{Mul, Sub};
+use pyo3::PyErr;
+use pyo3::exceptions::PyValueError;
 
 pub fn bsplev_single_f64(x: &f64, i: usize, k: &usize, t: &Vec<f64>, org_k: Option<usize>) -> f64 {
     let org_k: usize = org_k.unwrap_or(*k);
@@ -164,18 +166,23 @@ where
         left_n: usize,
         right_n: usize,
         allow_lsq: bool,
-    )
+    ) -> Result<(), PyErr>
     {
         if tau.len() != self.n && !(allow_lsq && tau.len() > self.n) {
-            panic!("`csolve` cannot complete if length of `tau` < n or `allow_lsq` is false.")
+            return Err(PyValueError::new_err(
+                "`csolve` cannot complete if length of `tau` < n or `allow_lsq` is false."
+            ))
         }
         if tau.len() != y.len() {
-            panic!("`tau` and `y` must have the same length.")
+            return Err(PyValueError::new_err(
+                "`tau` and `y` must have the same length."
+            ))
         }
         let b: Array2<f64> = self.bsplmatrix(tau, left_n, right_n);
         let ya: Array1<T> = Array1::from_vec(y.clone());
         let c: Array1<T> = fdsolve(&b.view(), &ya.view(), allow_lsq);
         self.c = Some(c);
+        Ok(())
     }
 
     pub fn bsplev(&self, x: &Vec<f64>, i: &usize) -> Vec<f64> {

src/splines/spline_py.rs

@@ -54,7 +54,7 @@ macro_rules! create_interface {
                 left_n: usize,
                 right_n: usize,
                 allow_lsq: bool
-            ) {
+            ) -> PyResult<()> {
                 self.inner.csolve(&tau, &y, left_n, right_n, allow_lsq)
             }