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Optimized taylorCos

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This commit is contained in:
Christophe Riccio 2016-11-21 00:06:05 +01:00
parent 3945098589
commit 1a95482b50
2 changed files with 117 additions and 3 deletions
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6
glm/gtx/fast_trigonometry.inl
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@ -9,9 +9,9 @@ namespace detail
{
return static_cast<T>(1)
- (x * x) * (1.f / 2.f)
+ (x * x * x * x) * (1.f / 24.f)
- (x * x * x * x * x * x) * (1.f / 720.f)
+ (x * x * x * x * x * x * x * x) (1.f / 40320.f);
+ ((x * x) * (x * x)) * (1.f / 24.f)
- (((x * x) * (x * x)) * (x * x)) * (1.f / 720.f)
+ (((x * x) * (x * x)) * ((x * x) * (x * x))) * (1.f / 40320.f);
}
template <typename T>

114
test/gtx/gtx_fast_trigonometry.cpp
View file

@ -426,10 +426,124 @@ namespace taylorCos
}
}//namespace taylorCos
namespace taylor2
{
glm::vec4 const AngleShift(0.0f, glm::pi<float>() * 0.5f, glm::pi<float>() * 1.0f, glm::pi<float>() * 1.5f);
float taylorCosA(float x)
{
return 1.f
- (x * x) * (1.f / 2.f)
+ (x * x * x * x) * (1.f / 24.f)
- (x * x * x * x * x * x) * (1.f / 720.f)
+ (x * x * x * x * x * x * x * x) * (1.f / 40320.f);
}
float taylorCosB(float x)
{
return 1.f
- (x * x) * (1.f / 2.f)
+ (x * x * x * x) * (1.f / 24.f)
- (x * x * x * x * x * x) * (1.f / 720.f)
+ (x * x * x * x * x * x * x * x) * (1.f / 40320.f);
}
float taylorCosC(float x)
{
return 1.f
- (x * x) * (1.f / 2.f)
+ ((x * x) * (x * x)) * (1.f / 24.f)
- (((x * x) * (x * x)) * (x * x)) * (1.f / 720.f)
+ (((x * x) * (x * x)) * ((x * x) * (x * x))) * (1.f / 40320.f);
}
int perf_taylorCosA(float Begin, float End, std::size_t Samples)
{
std::vector<float> Results;
Results.resize(Samples);
float Steps = (End - Begin) / Samples;
std::clock_t const TimeStampBegin = std::clock();
for(std::size_t i = 0; i < Samples; ++i)
Results[i] = taylorCosA(AngleShift.x + Begin + Steps * i);
std::clock_t const TimeStampEnd = std::clock();
std::printf("taylorCosA %ld clocks\n", TimeStampEnd - TimeStampBegin);
int Error = 0;
for(std::size_t i = 0; i < Samples; ++i)
Error += Results[i] >= -1.0f && Results[i] <= 1.0f ? 0 : 1;
return Error;
}
int perf_taylorCosB(float Begin, float End, std::size_t Samples)
{
std::vector<float> Results;
Results.resize(Samples);
float Steps = (End - Begin) / Samples;
std::clock_t const TimeStampBegin = std::clock();
for(std::size_t i = 0; i < Samples; ++i)
Results[i] = taylorCosB(AngleShift.x + Begin + Steps * i);
std::clock_t const TimeStampEnd = std::clock();
std::printf("taylorCosB %ld clocks\n", TimeStampEnd - TimeStampBegin);
int Error = 0;
for(std::size_t i = 0; i < Samples; ++i)
Error += Results[i] >= -1.0f && Results[i] <= 1.0f ? 0 : 1;
return Error;
}
int perf_taylorCosC(float Begin, float End, std::size_t Samples)
{
std::vector<float> Results;
Results.resize(Samples);
float Steps = (End - Begin) / Samples;
std::clock_t const TimeStampBegin = std::clock();
for(std::size_t i = 0; i < Samples; ++i)
Results[i] = taylorCosC(AngleShift.x + Begin + Steps * i);
std::clock_t const TimeStampEnd = std::clock();
std::printf("taylorCosC %ld clocks\n", TimeStampEnd - TimeStampBegin);
int Error = 0;
for(std::size_t i = 0; i < Samples; ++i)
Error += Results[i] >= -1.0f && Results[i] <= 1.0f ? 0 : 1;
return Error;
}
int perf(std::size_t Samples)
{
int Error = 0;
float const Begin = -glm::pi<float>();
float const End = glm::pi<float>();
Error += perf_taylorCosA(Begin, End, Samples);
Error += perf_taylorCosB(Begin, End, Samples);
Error += perf_taylorCosC(Begin, End, Samples);
return Error;
}
}//namespace taylor2
int main()
{
int Error(0);
Error += ::taylor2::perf(1000);
Error += ::taylorCos::test();
Error += ::taylorCos::perf(1000);