Upload files to "ex1G_dense_matrices_access"

ex1G_dense_matrices_access/sigmoid.h

@@ -0,0 +1,12 @@
+#pragma once
+#include <cmath>
+
+double sigmoid(double x)
+{
+    return 1./(1. + exp(-x));
+}
+
+double x_entry(size_t k, size_t nm)
+{
+    return (10.*k)/(nm - 1) - 5.;
+}