Improve conversion of complex numbers to PARI

sagemath · Mar 5, 2014 · 988c1f8 · 988c1f8
1 parent ccab985
commit 988c1f8
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 5 deletions.
diff --git a/src/sage/rings/complex_double.pyx b/src/sage/rings/complex_double.pyx
@@ -1054,21 +1054,28 @@ cdef class ComplexDoubleElement(FieldElement):
 
     cdef GEN _gen(self):
         cdef GEN y
-        y = cgetg(3, t_COMPLEX)    # allocate space for a complex number
-        set_gel(y, 1, pari.double_to_GEN(self._complex.dat[0]))
-        set_gel(y, 2, pari.double_to_GEN(self._complex.dat[1]))
+        if self._complex.dat[1] == 0:
+            # Return t_REAL
+            y = pari.double_to_GEN(self._complex.dat[0])
+        else:
+            # Return t_COMPLEX
+            y = cgetg(3, t_COMPLEX)
+            set_gel(y, 1, pari.double_to_GEN(self._complex.dat[0]))
+            set_gel(y, 2, pari.double_to_GEN(self._complex.dat[1]))
         return y
 
     def _pari_(self):
         """
-        Return PARI version of ``self``.
+        Return PARI version of ``self``, as ``t_COMPLEX`` or ``t_REAL``.
 
         EXAMPLES::
 
             sage: CDF(1,2)._pari_()
             1.00000000000000 + 2.00000000000000*I
             sage: pari(CDF(1,2))
             1.00000000000000 + 2.00000000000000*I
+            sage: pari(CDF(2.0))
+            2.00000000000000
         """
         pari_catch_sig_on()
         return pari.new_gen(self._gen())

diff --git a/src/sage/rings/complex_number.pyx b/src/sage/rings/complex_number.pyx
@@ -544,7 +544,8 @@ cdef class ComplexNumber(sage.structure.element.FieldElement):
 
     def _pari_(self):
         r"""
-        Coerces ``self`` into a Pari ``complex`` object.
+        Coerces ``self`` into a PARI ``t_COMPLEX`` object,
+        or a ``t_REAL`` if ``self`` is real.
 
         EXAMPLES:
 
@@ -553,13 +554,22 @@ cdef class ComplexNumber(sage.structure.element.FieldElement):
             sage: a = ComplexNumber(2,1)
             sage: pari(a)
             2.00000000000000 + 1.00000000000000*I
+            sage: pari(a).type()
+            't_COMPLEX'
             sage: type(pari(a))
             <type 'sage.libs.pari.gen.gen'>
             sage: a._pari_()
             2.00000000000000 + 1.00000000000000*I
             sage: type(a._pari_())
             <type 'sage.libs.pari.gen.gen'>
+            sage: a = CC(pi)
+            sage: pari(a)
+            3.14159265358979
+            sage: pari(a).type()
+            't_REAL'
         """
+        if self.is_real():
+            return self.real()._pari_()
         return sage.libs.pari.all.pari.complex(self.real()._pari_(), self.imag()._pari_())
 
     def _mpmath_(self, prec=None, rounding=None):