Add BLI_math_solver, where non-linear solvers should be.

For now, only has an eigen solver for 3×3 (symmetric) matrix.

1 files changed, 61 insertions, 0 deletions

diff --git a/source/blender/blenlib/intern/math_solvers.c b/source/blender/blenlib/intern/math_solvers.c
new file mode 100644
index 00000000000..2f962714c8c
--- /dev/null
+++ b/source/blender/blenlib/intern/math_solvers.c
@@ -0,0 +1,61 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2015 by Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ * */
+
+/** \file blender/blenlib/intern/math_solvers.c
+ *  \ingroup bli
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_math.h"
+#include "BLI_utildefines.h"
+
+#include "BLI_strict_flags.h"
+
+#include "eigen3_capi.h"
+
+/********************************** Eigen Solvers *********************************/
+
+/**
+ * \brief Compute the eigen values and/or vectors of given 3D symmetric (aka adjoint) matrix.
+ *
+ * \param m3 the 3D symmetric matrix.
+ * \return r_eigen_values the computed eigen values (NULL if not needed).
+ * \return r_eigen_vectors the computed eigen vectors (NULL if not needed).
+ */
+bool BLI_eigen_solve_selfadjoint_m3(const float m3[3][3], float r_eigen_values[3], float r_eigen_vectors[3][3])
+{
+#ifndef NDEBUG
+	/* We must assert given matrix is self-adjoint (i.e. symmetric) */
+	if ((m3[0][1] != m3[1][0]) ||
+	    (m3[0][2] != m3[2][0]) ||
+	    (m3[1][2] != m3[2][1]))
+	{
+		BLI_assert(0);
+	}
+#endif
+
+	return EG3_self_adjoint_eigen_solve(3, (const float *)m3, r_eigen_values, (float *)r_eigen_vectors);
+}