From 347af1c908b3382b3762cfc442fc84716ada93c1 Mon Sep 17 00:00:00 2001
From: Anders Olsson <anders.e.olsson@gmail.com>
Date: Thu, 28 Apr 2022 10:23:37 +0200
Subject: [PATCH] Added test for linalg::solve. Fix bug in fitter (wrong
 argument order)

---
 src/fitter/recursive.rs | 14 +++++++-------
 src/linalg.rs           | 26 +++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/src/fitter/recursive.rs b/src/fitter/recursive.rs
index ee65beb..44326d7 100644
--- a/src/fitter/recursive.rs
+++ b/src/fitter/recursive.rs
@@ -264,9 +264,10 @@ impl<K: Kernel> Fitter for Recursive<K> {
                 };
 
                 // RTS update using the right neighbor.
-                let a = self.kernel.transition(ts[i], self.ts[(j + 1) as usize]);
-                let a = a.dot(&p);
-                let b = self.p_p[(j + 1) as usize].clone();
+                let a = self.p_p[(j + 1) as usize].clone();
+
+                let b = self.kernel.transition(ts[i], self.ts[(j + 1) as usize]);
+                let b = b.dot(&p);
 
                 let g = crate::linalg::solve(a, b);
                 let g = g.t();
@@ -327,7 +328,6 @@ mod tests {
     extern crate blas_src;
 
     use approx::assert_relative_eq;
-    use rand::{distributions::Standard, thread_rng, Rng};
 
     use crate::kernel::Matern32;
 
@@ -463,7 +463,7 @@ mod tests {
         fitter.fit();
 
         // Estimation
-        eprintln!("{:#?}", fitter.ms);
+        // eprintln!("{:#?}", fitter.ms);
 
         assert_relative_eq!(
             Array1::from(fitter.ms.clone()),
@@ -479,8 +479,8 @@ mod tests {
         // Prediction.
         let (ms, vs) = fitter.predict(data_ts_pred());
 
-        assert_relative_eq!(Array1::from(ms), data_mean_pred(), max_relative = 0.0000001);
-        assert_relative_eq!(Array1::from(vs), data_var_pred(), max_relative = 0.0000001);
+        assert_relative_eq!(Array1::from(ms), data_mean_pred(), max_relative = 0.000001);
+        assert_relative_eq!(Array1::from(vs), data_var_pred(), max_relative = 0.000001);
 
         /*
         # Log-likelihood.
diff --git a/src/linalg.rs b/src/linalg.rs
index 1d4a5dd..9127cbf 100644
--- a/src/linalg.rs
+++ b/src/linalg.rs
@@ -29,7 +29,7 @@ pub fn solve(mut a: Array2<f64>, mut b: Array2<f64>) -> Array2<f64> {
     let mut ipiv = vec![0; n as usize];
 
     let (a_slice, layout) = as_slice_with_layout_mut(&mut a).expect("Matrix `a` not contiguous.");
-    let (b_slice, _) = as_slice_with_layout_mut(&mut b).expect("Matrix `a` not contiguous.");
+    let (b_slice, _) = as_slice_with_layout_mut(&mut b).expect("Matrix `b` not contiguous.");
 
     unsafe {
         info = lapacke::dgesv(layout, n, nrhs, a_slice, lda, &mut ipiv, b_slice, ldb);
@@ -39,3 +39,27 @@ pub fn solve(mut a: Array2<f64>, mut b: Array2<f64>) -> Array2<f64> {
 
     b
 }
+
+#[cfg(test)]
+mod tests {
+    use approx::assert_relative_eq;
+
+    use super::*;
+
+    #[test]
+    fn test_solve() {
+        let a = array![[2.0, 0.0], [0.0, 6.0]];
+        let b = array![[1.9645574, 0.56996938], [-0.56996938, 3.91924033]];
+
+        let e = array![[0.9822787, 0.28498469], [-0.0949949, 0.65320672]];
+
+        assert_relative_eq!(solve(a, b), e, max_relative = 0.0000001);
+
+        let a = array![[1.22650294, 0.67685001], [0.67685001, 5.34978493]];
+        let b = array![[1.00213885, 1.47494613], [-0.03356356, 2.14214437]];
+
+        let e = array![[0.88212208, 1.0552697], [-0.11787911, 0.26690514]];
+
+        assert_relative_eq!(solve(a, b), e, max_relative = 0.0000001);
+    }
+}