1 files changed, 56 insertions, 0 deletions
diff --git a/demos/mix_eigen_and_c/example.c b/demos/mix_eigen_and_c/example.c
new file mode 100644
index 000000000..431808c81
--- /dev/null
+++ b/demos/mix_eigen_and_c/example.c
@@ -0,0 +1,56 @@
+#include "binary_library.h"
+#include "stdio.h"
+
+void demo_MatrixXd()
+{
+  struct C_MatrixXd *matrix1, *matrix2, *result;
+  printf("*** demo_MatrixXd ***\n");
+  
+  matrix1 = MatrixXd_new(3, 3);
+  MatrixXd_set_zero(matrix1);
+  MatrixXd_set_coeff(matrix1, 0, 1, 2.5);
+  MatrixXd_set_coeff(matrix1, 1, 0, 1.4);
+  printf("Here is matrix1:\n");
+  MatrixXd_print(matrix1);
+
+  matrix2 = MatrixXd_new(3, 3);
+  MatrixXd_multiply(matrix1, matrix1, matrix2);
+  printf("Here is matrix1*matrix1:\n");
+  MatrixXd_print(matrix2);
+
+  MatrixXd_delete(matrix1);
+  MatrixXd_delete(matrix2);
+}
+
+// this helper function takes a plain C array and prints it in one line
+void print_array(double *array, int n)
+{
+  struct C_Map_MatrixXd *m = Map_MatrixXd_new(array, 1, n);
+  Map_MatrixXd_print(m);
+  Map_MatrixXd_delete(m);
+}
+
+void demo_Map_MatrixXd()
+{
+  struct C_Map_MatrixXd *map;
+  double array[5];
+  int i;
+  printf("*** demo_Map_MatrixXd ***\n");
+  
+  for(i = 0; i < 5; ++i) array[i] = i;
+  printf("Initially, the array is:\n");
+  print_array(array, 5);
+  
+  map = Map_MatrixXd_new(array, 5, 1);
+  Map_MatrixXd_add(map, map, map);
+  Map_MatrixXd_delete(map);
+
+  printf("Now the array is:\n");
+  print_array(array, 5);
+}
+
+int main()
+{
+  demo_MatrixXd();
+  demo_Map_MatrixXd();
+}