From 9e222734a8a7cfae28792bcfd311e955caf6eac8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Villemot?= <sebastien@dynare.org>
Date: Wed, 27 Nov 2019 16:54:01 +0100
Subject: [PATCH] Bytecode: fix logic in routine that substracts two sparse
matrices
The logic of the dynSparseMatrix::Sparse_substract_SA_SB() routine was
incorrect.
In some cases, it would read past the last nonzero elements of the A matrix,
and consequently write past the number of allocated nonzero elements of the C
matrix.
This would lead to crashes and, probably, to wrong results under certain
circumstances.
Closes: #1652
---
mex/sources/bytecode/SparseMatrix.cc | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mex/sources/bytecode/SparseMatrix.cc b/mex/sources/bytecode/SparseMatrix.cc
index 1f4cb7fb67..322b6943f2 100644
--- a/mex/sources/bytecode/SparseMatrix.cc
+++ b/mex/sources/bytecode/SparseMatrix.cc
@@ -2618,7 +2618,7 @@ dynSparseMatrix::Sparse_substract_SA_SB(mxArray *A_m, mxArray *B_m)
C_j[A_col+1] = nze_C++;
C_col = A_col;
}
- else if (A_row < B_row || (nze_B >= total_nze_B && nze_A < total_nze_A))
+ else if ((A_row < B_row && nze_A < total_nze_A) || nze_B == total_nze_B)
{
C_d[nze_C] = A_d[nze_A++];
C_i[nze_C] = A_row;
@@ -2637,7 +2637,7 @@ dynSparseMatrix::Sparse_substract_SA_SB(mxArray *A_m, mxArray *B_m)
C_col = B_col;
}
}
- else if (A_col < B_col || (nze_B >= total_nze_B && nze_A < total_nze_A))
+ else if ((A_col < B_col && nze_A < total_nze_A) || nze_B == total_nze_B)
{
C_d[nze_C] = A_d[nze_A++];
C_i[nze_C] = A_row;
--
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