From 77235f4f3fbb705d177fc36cadf2b247e913bef9 Mon Sep 17 00:00:00 2001
From: Toshiki Teramura <toshiki.teramura@gmail.com>
Date: Thu, 29 Sep 2022 20:54:44 +0900
Subject: [PATCH] InvWork

---
 lax/src/solve.rs | 63 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/lax/src/solve.rs b/lax/src/solve.rs
index d0f764fd..89dc1113 100644
--- a/lax/src/solve.rs
+++ b/lax/src/solve.rs
@@ -64,6 +64,69 @@ pub trait Solve_: Scalar + Sized {
     fn solve(l: MatrixLayout, t: Transpose, a: &[Self], p: &Pivot, b: &mut [Self]) -> Result<()>;
 }
 
+pub struct InvWork<T: Scalar> {
+    pub layout: MatrixLayout,
+    pub work: Vec<MaybeUninit<T>>,
+}
+
+pub trait InvWorkImpl: Sized {
+    type Elem: Scalar;
+    fn new(layout: MatrixLayout) -> Result<Self>;
+    fn calc(&mut self, a: &mut [Self::Elem], p: &Pivot) -> Result<()>;
+}
+
+macro_rules! impl_inv_work {
+    ($s:ty, $tri:path) => {
+        impl InvWorkImpl for InvWork<$s> {
+            type Elem = $s;
+
+            fn new(layout: MatrixLayout) -> Result<Self> {
+                let (n, _) = layout.size();
+                let mut info = 0;
+                let mut work_size = [Self::Elem::zero()];
+                unsafe {
+                    $tri(
+                        &n,
+                        std::ptr::null_mut(),
+                        &layout.lda(),
+                        std::ptr::null(),
+                        AsPtr::as_mut_ptr(&mut work_size),
+                        &(-1),
+                        &mut info,
+                    )
+                };
+                info.as_lapack_result()?;
+                let lwork = work_size[0].to_usize().unwrap();
+                let work = vec_uninit(lwork);
+                Ok(InvWork { layout, work })
+            }
+
+            fn calc(&mut self, a: &mut [Self::Elem], ipiv: &Pivot) -> Result<()> {
+                let lwork = self.work.len().to_i32().unwrap();
+                let mut info = 0;
+                unsafe {
+                    $tri(
+                        &self.layout.len(),
+                        AsPtr::as_mut_ptr(a),
+                        &self.layout.lda(),
+                        ipiv.as_ptr(),
+                        AsPtr::as_mut_ptr(&mut self.work),
+                        &lwork,
+                        &mut info,
+                    )
+                };
+                info.as_lapack_result()?;
+                Ok(())
+            }
+        }
+    };
+}
+
+impl_inv_work!(c64, lapack_sys::zgetri_);
+impl_inv_work!(c32, lapack_sys::cgetri_);
+impl_inv_work!(f64, lapack_sys::dgetri_);
+impl_inv_work!(f32, lapack_sys::sgetri_);
+
 macro_rules! impl_solve {
     ($scalar:ty, $getrf:path, $getri:path, $getrs:path) => {
         impl Solve_ for $scalar {