fix #1205 - diag may return wrong sub- or superdiagonals

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 1.6.0 (UNRELEASED)
+
+### Fixed
+
+- [#1205](http://github.com/nelson-lang/nelson/issues/1205) `diag` may return wrong sub-diagonals.
+
 ## 1.5.0 (2024-05-31)
 
 ### Added

modules/constructors_functions/tests/bug_github_issue_#1205.m

@@ -0,0 +1,75 @@
+%=============================================================================
+% Copyright (c) 2017 Allan CORNET (Nelson)
+%=============================================================================
+% This file is part of the Nelson.
+%=============================================================================
+% LICENCE_BLOCK_BEGIN
+% SPDX-License-Identifier: LGPL-3.0-or-later
+% LICENCE_BLOCK_END
+%=============================================================================
+% <-- Issue URL -->
+% https://github.com/nelson-lang/nelson/issues/1205
+% <-- Short Description -->
+% `diag` may return wrong sub- or superdiagonals
+%=============================================================================
+A = vander(1:3);
+R = diag(A)';
+REF = [1 2 1];
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:3);
+R = diag(A, 1)';
+REF = [1 1];
+assert_isequal(R, REF);
+%=============================================================================
+R = diag(A, 2)';
+REF = 1;
+assert_isequal(R, REF);
+%=============================================================================
+R = diag(A, 3)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+R = diag(A, 4)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+R = diag(A, 5)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:4);
+R = diag(A, 4)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:4);
+R = diag(A, 5)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:4);
+R = diag(A, 45)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:3);
+R = diag(A, -1)';
+REF = [4 3];
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:3);
+R = diag(A, -2)';
+REF = 9;
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:3);
+R = diag(A, -3)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================
+A = vander(1:3);
+R = diag(A, -4)';
+REF = zeros(1, 0);
+assert_isequal(R, REF);
+%=============================================================================

modules/types/src/cpp/ArrayOf_Constructors.cpp

@@ -41,6 +41,10 @@ ArrayOf::getDiagonal(int64 diagonalOrder)
     int64 srcIndex;
     void* qp;
     if (diagonalOrder < 0) {
+        if (diagonalOrder < -(int64)(rows)) {
+            diagonalOrder = -(int64)(rows);
+        }
+
         outLen = (rows + diagonalOrder) < cols ? (rows + diagonalOrder) : cols;
         outLen = (outLen < 0) ? 0 : outLen;
         if (outLen == 0) {
@@ -57,6 +61,9 @@ ArrayOf::getDiagonal(int64 diagonalOrder)
             copyElements(srcIndex, qp, i, 1);
         }
     } else {
+        if (diagonalOrder > (int64)cols) {
+            diagonalOrder = (int64)cols;
+        }
         outLen = rows < (cols - diagonalOrder) ? rows : (cols - diagonalOrder);
         outLen = (outLen < 0) ? 0 : outLen;
         if (outLen == 0) {