1 files changed, 52 insertions, 0 deletions
diff --git a/src/strats.c b/src/strats.c
new file mode 100644
index 0000000..1c5ce53
--- /dev/null
+++ b/src/strats.c
@@ -0,0 +1,52 @@
+#include <stdlib.h>
+
+static inline void
+product (size_t n,
+	 size_t omega,
+	 const double *restrict temporal_dependency,
+	 const double *restrict vector,
+	 double *restrict out)
+{
+  size_t i;
+  #pragma omp parallel for
+  for (i = 0; i < n; i++)
+    {
+      size_t j;
+      out[i] = 0;
+      /* Backward: */
+      for (j = 0; j < omega; j++)
+	{
+	  if (i > j)
+	    {
+	      const double x = vector[i - j - 1];
+	      const double coefficient = temporal_dependency[j];
+	      out[i] += coefficient * (vector[i] - x);
+	    }
+	}
+      /* Forward: */
+      for (j = 0; j < omega; j++)
+	{
+	  if (i + j + 1 < n)
+	    {
+	      const double x = vector[i + j + 1];
+	      const double coefficient = temporal_dependency[j];
+	      out[i] += coefficient * (vector[i] - x);
+	    }
+	}
+    }
+}
+
+void
+strats_compute_laplacian_matrix_product (int *n,
+					 int *d,
+					 int *omega,
+					 double *temporal_dependency,
+					 double *x,
+					 double *out)
+{
+  int j;
+  for (j = 0; j < *d; j++)
+    {
+      product (*n, *omega, temporal_dependency, x + j * (*n), out + j * (*n));
+    }
+}