[GRASS-SVN] r61237 - grass-addons/grass7/raster3d/r3.flow

[svn_grass at osgeo.org]

Author: annakrat
Date: 2014-07-10 16:00:30 -0700 (Thu, 10 Jul 2014)
New Revision: 61237

Added:
   grass-addons/grass7/raster3d/r3.flow/gradient.c
   grass-addons/grass7/raster3d/r3.flow/gradient.h
Modified:
   grass-addons/grass7/raster3d/r3.flow/r3flow_structs.h
Log:
r3.flow: added gradient computation (not used yet)

Added: grass-addons/grass7/raster3d/r3.flow/gradient.c
===================================================================
--- grass-addons/grass7/raster3d/r3.flow/gradient.c	                        (rev 0)
+++ grass-addons/grass7/raster3d/r3.flow/gradient.c	2014-07-10 23:00:30 UTC (rev 61237)
@@ -0,0 +1,84 @@
+/*!
+   \file gradient.c
+
+   \brief Gradient computation
+
+    Gradient computation (second order approximation)
+    using central differencing scheme (plus forward and backward
+    difference of second order approx.)
+   
+   (C) 2014 by the GRASS Development Team
+
+   This program is free software under the GNU General Public
+   License (>=v2).  Read the file COPYING that comes with GRASS
+   for details.
+
+   \author Anna Petrasova
+ */
+#include "r3flow_structs.h"
+
+void gradient(struct Array *array, double *step,
+	      struct Array *grad_x, struct Array *grad_y,
+	      struct Array *grad_z)
+{
+    int col, row, depth;
+
+    for (depth = 0; depth < array->sz; depth++) {
+	for (row = 0; row < array->sy; row++) {
+	    ACCESS(grad_x, 0, row, depth) =
+		(-3 * ACCESS(array, 0, row, depth) +
+		 4 * ACCESS(array, 1, row, depth) -
+		 ACCESS(array, 2, row, depth)) / (2 * step[0]);
+
+	    ACCESS(grad_x, array->sx - 1, row, depth) =
+		(3 * ACCESS(array, array->sx - 1, row, depth) -
+		 4 * ACCESS(array, array->sx - 2, row, depth) +
+		 ACCESS(array, array->sx - 3, row, depth)) / (2 * step[0]);
+
+	    for (col = 0; col < array->sx; col++) {
+		ACCESS(grad_x, col, row, depth) =
+		    (ACCESS(array, col + 1, row, depth) -
+		     ACCESS(array, col - 1, row, depth)) / (2 * step[0]);
+	    }
+	}
+    }
+    for (depth = 0; depth < array->sz; depth++) {
+	for (col = 0; col < array->sx; col++) {
+	    ACCESS(grad_y, col, 0, depth) =
+		(-3 * ACCESS(array, col, 0, depth) +
+		 4 * ACCESS(array, col, 1, depth) -
+		 ACCESS(array, col, 2, depth)) / (2 * step[1]);
+
+	    ACCESS(grad_y, col, array->sy - 1, depth) =
+		(3 * ACCESS(array, col, array->sy - 1, depth) -
+		 4 * ACCESS(array, col, array->sy - 2, depth) +
+		 ACCESS(array, col, array->sy - 3, depth)) / (2 * step[1]);
+
+	    for (row = 0; row < array->sy; row++) {
+		ACCESS(grad_y, col, row, depth) =
+		    (ACCESS(array, col, row + 1, depth) -
+		     ACCESS(array, col, row - 1, depth)) / (2 * step[1]);
+	    }
+	}
+    }
+    for (row = 0; row < array->sy; row++) {
+	for (col = 0; col < array->sx; col++) {
+	    ACCESS(grad_z, col, row, 0) =
+		(-3 * ACCESS(array, col, row, 0) +
+		 4 * ACCESS(array, col, row, 1) -
+		 ACCESS(array, col, row, 2)) / (2 * step[2]);
+
+	    ACCESS(grad_z, col, row, array->sz - 1) =
+		(3 * ACCESS(array, col, row, array->sz - 1) -
+		 4 * ACCESS(array, col, row, array->sz - 2) +
+		 ACCESS(array, col, row, array->sz - 3)) / (2 * step[2]);
+
+	    for (depth = 0; depth < array->sz; depth++) {
+		/* is minus here? */
+		ACCESS(grad_y, col, row, depth) =
+		    -(ACCESS(array, col, row, depth + 1) -
+		      ACCESS(array, col, row, depth - 1)) / (2 * step[2]);
+	    }
+	}
+    }
+}


Property changes on: grass-addons/grass7/raster3d/r3.flow/gradient.c
___________________________________________________________________
Added: svn:mime-type
   + text/x-csrc
Added: svn:eol-style
   + native

Added: grass-addons/grass7/raster3d/r3.flow/gradient.h
===================================================================
--- grass-addons/grass7/raster3d/r3.flow/gradient.h	                        (rev 0)
+++ grass-addons/grass7/raster3d/r3.flow/gradient.h	2014-07-10 23:00:30 UTC (rev 61237)
@@ -0,0 +1,9 @@
+#ifndef GRADIENT_H
+#define GRADIENT_H
+
+#include "r3flow_structs.h"
+
+void gradient(struct Array *array, double *step,
+	      struct Array *grad_x, struct Array *grad_y,
+	      struct Array *grad_z);
+#endif // GRADIENT_H


Property changes on: grass-addons/grass7/raster3d/r3.flow/gradient.h
___________________________________________________________________
Added: svn:mime-type
   + text/x-chdr
Added: svn:eol-style
   + native

Modified: grass-addons/grass7/raster3d/r3.flow/r3flow_structs.h
===================================================================
--- grass-addons/grass7/raster3d/r3.flow/r3flow_structs.h	2014-07-10 19:03:00 UTC (rev 61236)
+++ grass-addons/grass7/raster3d/r3.flow/r3flow_structs.h	2014-07-10 23:00:30 UTC (rev 61237)
@@ -21,4 +21,14 @@
     int limit;
 };
 
+struct Array
+{
+    double *array;
+    int sx;
+    int sy;
+    int sz;
+};
+
+#define ACCESS(arr, x, y, z) ((arr)->array[(arr)->sx * (arr)->sy * (z) + (arr)->sx * (y) + (x)])
+
 #endif // R3FLOW_STRUCTS_H