From 4a8ef93786f697ca122aeafe2088d6bdffe512db Mon Sep 17 00:00:00 2001
From: Vaibhav Yenamandra <vaibhav-y@users.noreply.github.com>
Date: Wed, 15 Jun 2016 10:02:36 +0530
Subject: [PATCH] Add ability to assign ruby complex types to
 GSL::Matrix::Complex (#38)

* * Added a case for `T_COMPLEX` in rb_gsl_complex_new(1..2) and rb_gsl_obj_to_gsl_complex(1)
* Currently the ops on `::Complex` number is handled via rb_funcall(2..)

* Added a test for creating `GSL::Complex` by passing `Complex ` type to `GSL::Complex#alloc`

* There is an added cost due to the call to rb_funcall(2..) being used since the @real, @image ivars appear to be unset, in addition to this, struct RComplex is not publicly exposed and to use TypedData_Get_Struct(3) this struct would need to be replicated along with all its dependants.

* Fixed a typo that led to failing tests
---
 ext/gsl_native/complex.c | 12 +++++++++++-
 test/gsl/complex_test.rb | 13 ++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/ext/gsl_native/complex.c b/ext/gsl_native/complex.c
index 40b1ac5e..a637787d 100644
--- a/ext/gsl_native/complex.c
+++ b/ext/gsl_native/complex.c
@@ -41,6 +41,11 @@ gsl_complex rb_gsl_obj_to_gsl_complex(VALUE obj, gsl_complex *z)
     if (!NIL_P(vre)) GSL_SET_REAL(z, NUM2DBL(vre));
     if (!NIL_P(vim)) GSL_SET_IMAG(z, NUM2DBL(vim));
     break;
+  case T_COMPLEX:
+    vre = rb_funcall(obj, rb_intern("real"), 0);
+    vim = rb_funcall(obj, rb_intern("imag"), 0);
+    *z = gsl_complex_rect(NUM2DBL(vre), NUM2DBL(vim));
+    break;
   case T_FLOAT:
   case T_FIXNUM:
   case T_BIGNUM:
@@ -63,7 +68,7 @@ gsl_complex rb_gsl_obj_to_gsl_complex(VALUE obj, gsl_complex *z)
 static VALUE rb_gsl_complex_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_complex *c = NULL;
-  VALUE obj;
+  VALUE obj, vre, vim;
   obj = Data_Make_Struct(klass, gsl_complex, 0, free, c);
   switch (argc) {
   case 1:
@@ -71,6 +76,11 @@ static VALUE rb_gsl_complex_new(int argc, VALUE *argv, VALUE klass)
     case T_ARRAY:
       *c = ary2complex(argv[0]);
       break;
+    case T_COMPLEX:
+      vre = rb_funcall(argv[0], rb_intern("real"), 0);
+      vim = rb_funcall(argv[0], rb_intern("imag"), 0);
+      *c = gsl_complex_rect(NUM2DBL(vre), NUM2DBL(vim));
+      break;
     case T_FLOAT:
     case T_FIXNUM:
     case T_BIGNUM:
diff --git a/test/gsl/complex_test.rb b/test/gsl/complex_test.rb
index 07e996e4..a1a01167 100644
--- a/test/gsl/complex_test.rb
+++ b/test/gsl/complex_test.rb
@@ -16,5 +16,16 @@ def test_complex
         'gsl_complex_polar imag part at (r=%g,t=%g)' % [r, t]
     }
   end
-
+  
+  # Test if it is possible to create a GSL::Complex from ::Complex
+  def test_rb_complex_creation
+    rb_comp = Complex(rand, rand)
+    
+    z = GSL::Complex.alloc(rb_comp)
+    
+    assert_rel z.real, rb_comp.real, GSL::DBL_EPSILON,
+      "gsl_complex real part.  Re(#{rb_comp}) = #{z.real}"
+    assert_rel z.imag, rb_comp.imag, GSL::DBL_EPSILON,
+      "gsl_complex imag part.  Im(#{rb_comp}) = #{z.imag}"
+  end
 end