From 3182a07ee230aa26d86c239c7a68aa6f55e9c855 Mon Sep 17 00:00:00 2001
From: Sungho Shin <sshin@anl.gov>
Date: Fri, 12 Apr 2024 09:44:08 -0500
Subject: [PATCH] fix for empty hessian/jacobian

---
 lib/MadNLPGPU/src/interface.jl     | 26 +++++++++++++++++---------
 lib/MadNLPTests/src/MadNLPTests.jl | 23 ++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/lib/MadNLPGPU/src/interface.jl b/lib/MadNLPGPU/src/interface.jl
index 73d12d43..d97e9cd6 100644
--- a/lib/MadNLPGPU/src/interface.jl
+++ b/lib/MadNLPGPU/src/interface.jl
@@ -143,13 +143,15 @@ function MadNLP.mul!(
     MadNLP.mul!(wx, kkt.hess_com , xx, alpha, beta)
     MadNLP.mul!(wx, kkt.hess_com', xx, alpha, one(T))
     MadNLP.mul!(wx, kkt.jt_csc,  xz, alpha, beta)
-    diag_operation(CUDABackend())(
-        wx, kkt.hess_com.nzVal, xx, alpha,
-        kkt.ext.diag_map_to,
-        kkt.ext.diag_map_fr;
-        ndrange = length(kkt.ext.diag_map_to)
-    )
-    synchronize(CUDABackend())
+    if !isempty(kkt.ext.diag_map_to)
+        diag_operation(CUDABackend())(
+            wx, kkt.hess_com.nzVal, xx, alpha,
+            kkt.ext.diag_map_to,
+            kkt.ext.diag_map_fr;
+            ndrange = length(kkt.ext.diag_map_to)
+        )
+        synchronize(CUDABackend())
+    end
 
     MadNLP.mul!(wz, kkt.jt_csc', xx, alpha, one(T))
     MadNLP.axpy!(-alpha, xz, ws)
@@ -190,7 +192,11 @@ function get_diagonal_mapping(colptr, rowval)
     inds1 = findall(map((x,y)-> ((x <= nnz) && (x != y)), @view(colptr[1:end-1]), @view(colptr[2:end])))
     ptrs = colptr[inds1]
     rows = rowval[ptrs]
-    inds2 = findall(inds1 .== rows)
+    inds2 = if isempty(rows)
+        similar(rowval,0)
+    else
+        findall(inds1 .== rows)
+    end
 
     return rows[inds2], ptrs[inds2]
 end
@@ -311,7 +317,9 @@ end
 
 
 function MadNLP.force_lower_triangular!(I::CuVector{T},J) where T
-    _force_lower_triangular!(CUDABackend())(I,J; ndrange=length(I))
+    if !isempty(I)
+        _force_lower_triangular!(CUDABackend())(I,J; ndrange=length(I))
+    end
 end
 
 @kernel function _set_colptr_kernel!(colptr, @Const(sym2), @Const(ptr2), @Const(guide))
diff --git a/lib/MadNLPTests/src/MadNLPTests.jl b/lib/MadNLPTests/src/MadNLPTests.jl
index 5062cd24..157fc3cf 100644
--- a/lib/MadNLPTests/src/MadNLPTests.jl
+++ b/lib/MadNLPTests/src/MadNLPTests.jl
@@ -111,7 +111,7 @@ end
 
 function test_madnlp(name,optimizer_constructor::Function,exclude; Arr = Array)
     @testset "$name" begin
-        for f in [infeasible,unbounded,lootsma,eigmina]
+        for f in [infeasible,unbounded,lootsma,eigmina,lp]
             !(string(f) in exclude) && f(optimizer_constructor; Arr = Arr)
         end
     end
@@ -331,6 +331,27 @@ function eigmina(optimizer_constructor::Function; Arr = Array)
     end
 end
 
+function lp(optimizer_constructor::Function; Arr = Array)
+    @testset "lp" begin
+        
+        model = Model()
+        @variable(model, x >= 0)
+        @variable(model, 0 <= y <= 3)
+        @objective(model, Min, 12x + 20y)
+        @constraint(model, c1, 6x + 8y >= 100)
+        @constraint(model, c2, 7x + 12y >= 120)
+
+        nlp = SparseWrapperModel(
+            Arr,
+            NLPModelsJuMP.MathOptNLPModel(m)
+        )
+        optimizer = optimizer_constructor()
+        result = MadNLP.madnlp(nlp; optimizer.options...)
+
+        @test result.status == MadNLP.SOLVE_SUCCEEDED
+    end
+end
+
 include("Instances/dummy_qp.jl")
 include("Instances/hs15.jl")
 include("Instances/nls.jl")