kfr

commit dfb5ea94d8c96e4d3384a1c7dc9fac109881a4a6
parent f3bc9bb02773324731c59ea811b8ca4c616b0212
Author: Stephen Larew <stephen@slarew.net>
Date:   Thu, 20 Feb 2020 12:28:51 -0800

add gen_expj

Diffstat:
M
include/kfr/base/generators.hpp
 | 
41
+++++++++++++++++++++++++++++++++++++++++
M
tests/base_test.cpp
 | 
12
++++++++++++

2 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/include/kfr/base/generators.hpp b/include/kfr/base/generators.hpp
@@ -136,6 +136,35 @@ protected:
     T vstep;
 };
 
+template <typename T, size_t width = vector_width<T>* bitness_const(1, 2),
+          std::enable_if_t<std::is_same<complex<deep_subtype<T>>, T>::value, int> = 0>
+struct generator_expj : generator<T, width, generator_expj<T, width>>
+{
+    using ST = deep_subtype<T>;
+
+    generator_expj(ST start_, ST step_)
+        : step(step_), alpha(2 * sqr(sin(width * step / 2))), beta(-sin(width * step))
+    {
+        this->resync(T(start_));
+    }
+    KFR_MEM_INTRINSIC void sync(T start) const CMT_NOEXCEPT { this->value = init_cossin(step, start.real()); }
+
+    KFR_MEM_INTRINSIC void next() const CMT_NOEXCEPT
+    {
+        this->value = ccomp(cdecom(this->value) -
+                            subadd(alpha * cdecom(this->value), beta * swap<2>(cdecom(this->value))));
+    }
+
+protected:
+    ST const step;
+    ST const alpha;
+    ST const beta;
+    CMT_NOINLINE static vec<T, width> init_cossin(ST w, ST phase)
+    {
+        return ccomp(cossin(dup(phase + enumerate<ST, width>() * w)));
+    }
+};
+
 template <typename T, size_t width = vector_width<T>* bitness_const(1, 2)>
 struct generator_exp2 : generator<T, width, generator_exp2<T, width>>
 {
@@ -255,6 +284,18 @@ KFR_FUNCTION internal::generator_exp<TF> gen_exp(T1 start, T2 step)
 /**
  * @brief Returns template expression that generates values using the following formula:
  * \f[
+    x_i = e^{ j ( start + i \cdot step ) }
+   \f]
+ */
+template <typename T1, typename T2, typename TF = complex<ftype<common_type<T1, T2>>>>
+KFR_FUNCTION internal::generator_expj<TF> gen_expj(T1 start, T2 step)
+{
+    return internal::generator_expj<TF>(start, step);
+}
+
+/**
+ * @brief Returns template expression that generates values using the following formula:
+ * \f[
     x_i = 2^{ start + i \cdot step }
    \f]
  */
diff --git a/tests/base_test.cpp b/tests/base_test.cpp
@@ -92,6 +92,18 @@ TEST(test_basic)
     CHECK(inrange(pack(1, 2, 3), 1, 1) == make_mask<int>(true, false, false));
 }
 
+TEST(test_gen_expj)
+{
+    kfr::univector<cbase> v = kfr::truncate(kfr::gen_expj(0.f, constants<float>::pi_s(2) * 0.1f), 1000);
+    CHECK(rms(cabs(v.slice(990) -
+                   univector<cbase>({ cbase(1., +0.00000000e+00), cbase(0.80901699, +5.87785252e-01),
+                                      cbase(0.30901699, +9.51056516e-01), cbase(-0.30901699, +9.51056516e-01),
+                                      cbase(-0.80901699, +5.87785252e-01), cbase(-1., +1.22464680e-16),
+                                      cbase(-0.80901699, -5.87785252e-01),
+                                      cbase(-0.30901699, -9.51056516e-01), cbase(0.30901699, -9.51056516e-01),
+                                      cbase(0.80901699, -5.87785252e-01) }))) < 0.00001);
+}
+
 } // namespace CMT_ARCH_NAME
 
 #ifndef KFR_NO_MAIN