egs: add support for MPI-based multi-component solves

1 files changed, 73 insertions, 0 deletions

diff --git a/components.h b/components.h
new file mode 100644
index 0000000..bc3c38f
--- /dev/null
+++ b/components.h
@@ -0,0 +1,73 @@
+/*
+ * Multi-component utility code
+ * Copyright 2019 Anton Khirnov <anton@khirnov.net>
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef MG2D_COMPONENTS_H
+#define MG2D_COMPONENTS_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+typedef struct Rect {
+    ptrdiff_t start[2];
+    size_t    size[2];
+} Rect;
+
+typedef struct DomainComponent {
+    /* points that belong to this component */
+    Rect interior;
+    /* interior + ghost points on the physical boundaries */
+    Rect exterior;
+    int  bnd_is_outer[4];
+} DomainComponent;
+
+typedef struct DomainGeometry {
+    size_t domain_size[2];
+
+    unsigned int  nb_components;
+    DomainComponent *components;
+} DomainGeometry;
+
+DomainGeometry *mg2di_dg_alloc(unsigned int nb_components);
+void            mg2di_dg_free(DomainGeometry **dg);
+
+int             mg2di_dg_copy(DomainGeometry **dst, const DomainGeometry *src);
+
+/**
+ * Compute the intersection of src1 and src2, store the result in dst.
+ */
+int mg2di_rect_intersect(Rect *dst, const Rect *src1, const Rect *src2);
+
+/**
+ * For the component <comp> in domain geometry <dg>, internal edges are
+ * rectangles along each non-outer boundary. Edge overlap with component <comp1>
+ * is the intersection of internal edges of <comp> and exterior of <comp1> (must
+ * necessarily be a rectangle).
+ *
+ * NB: edge overlap of a component with itself is empty.
+ *
+ * This function computes, for the given component <comp>
+ * - edge overlaps of <comp> with every component in dg (i.e. the ghost points
+ *   to be received from each remote component) - written into overlaps_recv
+ * - edge overlaps of every component in dg with <comp> (i.e. the ghost points
+ *   to be set to each remote component) - written into overlaps_send
+ */
+int mg2di_dg_edge_overlaps(Rect *overlaps_recv, Rect *overlaps_send,
+                           const DomainGeometry *dg, unsigned int comp,
+                           unsigned int edge_width);
+
+#endif // MG2D_COMPONENTS_H