Mention ptr_fun in docs for .unaryExpr()

1 files changed, 20 insertions, 0 deletions

diff --git a/doc/examples/class_CwiseUnaryOp_ptrfun.cpp b/doc/examples/class_CwiseUnaryOp_ptrfun.cpp
new file mode 100644
index 000000000..36706d8ed
--- /dev/null
+++ b/doc/examples/class_CwiseUnaryOp_ptrfun.cpp
@@ -0,0 +1,20 @@
+#include <Eigen/Core>
+#include <iostream>
+using namespace Eigen;
+using namespace std;
+
+// define function to be applied coefficient-wise
+double ramp(double x)
+{
+  if (x > 0)
+    return x;
+  else 
+    return 0;
+}
+
+int main(int, char**)
+{
+  Matrix4d m1 = Matrix4d::Random();
+  cout << m1 << endl << "becomes: " << endl << m1.unaryExpr(ptr_fun(ramp)) << endl;
+  return 0;
+}