optimize similarity template (#2227)

* optimize similarity template
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* code opt
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

core/src/index/thirdparty/faiss/impl/ScalarQuantizerCodec.h

@@ -313,70 +313,18 @@ struct SimilarityL2<1> {
 
 /* as same as SimilarityL2<1>, let build pass */
 template<>
-struct SimilarityL2<8> {
+struct SimilarityL2<8> : SimilarityL2<1> {
     static constexpr int simdwidth = 1;
     static constexpr MetricType metric_type = METRIC_L2;
-
-    const float *y, *yi;
-
-    explicit SimilarityL2 (const float * y): y(y) {}
-
-    /******* scalar accumulator *******/
-
-    float accu;
-
-    void begin () {
-        accu = 0;
-        yi = y;
-    }
-
-    void add_component (float x) {
-        float tmp = *yi++ - x;
-        accu += tmp * tmp;
-    }
-
-    void add_component_2 (float x1, float x2) {
-        float tmp = x1 - x2;
-        accu += tmp * tmp;
-    }
-
-    float result () {
-        return accu;
-    }
+    explicit SimilarityL2 (const float * y) : SimilarityL2<1>(y) {}
 };
 
 /* as same as SimilarityL2<1>, let build pass */
 template<>
-struct SimilarityL2<16> {
+struct SimilarityL2<16> : SimilarityL2<1> {
     static constexpr int simdwidth = 1;
     static constexpr MetricType metric_type = METRIC_L2;
-
-    const float *y, *yi;
-
-    explicit SimilarityL2 (const float * y): y(y) {}
-
-    /******* scalar accumulator *******/
-
-    float accu;
-
-    void begin () {
-        accu = 0;
-        yi = y;
-    }
-
-    void add_component (float x) {
-        float tmp = *yi++ - x;
-        accu += tmp * tmp;
-    }
-
-    void add_component_2 (float x1, float x2) {
-        float tmp = x1 - x2;
-        accu += tmp * tmp;
-    }
-
-    float result () {
-        return accu;
-    }
+    explicit SimilarityL2 (const float * y) : SimilarityL2<1>(y) {}
 };
 
 
@@ -414,62 +362,18 @@ struct SimilarityIP<1> {
 
 /* as same as SimilarityIP<1>, let build pass */
 template<>
-struct SimilarityIP<8> {
+struct SimilarityIP<8> : SimilarityIP<1> {
     static constexpr int simdwidth = 1;
     static constexpr MetricType metric_type = METRIC_INNER_PRODUCT;
-    const float *y, *yi;
-
-    float accu;
-
-    explicit SimilarityIP (const float * y):
-        y (y) {}
-
-    void begin () {
-        accu = 0;
-        yi = y;
-    }
-
-    void add_component (float x) {
-        accu +=  *yi++ * x;
-    }
-
-    void add_component_2 (float x1, float x2) {
-        accu +=  x1 * x2;
-    }
-
-    float result () {
-        return accu;
-    }
+    explicit SimilarityIP (const float * y) : SimilarityIP<1>(y) {}
 };
 
 /* as same as SimilarityIP<1>, let build pass */
 template<>
-struct SimilarityIP<16> {
+struct SimilarityIP<16> : SimilarityIP<1> {
     static constexpr int simdwidth = 1;
     static constexpr MetricType metric_type = METRIC_INNER_PRODUCT;
-    const float *y, *yi;
-
-    float accu;
-
-    explicit SimilarityIP (const float * y):
-        y (y) {}
-
-    void begin () {
-        accu = 0;
-        yi = y;
-    }
-
-    void add_component (float x) {
-        accu +=  *yi++ * x;
-    }
-
-    void add_component_2 (float x1, float x2) {
-        accu +=  x1 * x2;
-    }
-
-    float result () {
-        return accu;
-    }
+    explicit SimilarityIP (const float * y) : SimilarityIP<1>(y) {}
 };
 
 

core/src/index/thirdparty/faiss/impl/ScalarQuantizerCodec_avx.h

@@ -482,40 +482,10 @@ struct SimilarityL2_avx<8> {
 
 /* as same as SimilarityL2<8>, let build pass */
 template<>
-struct SimilarityL2_avx<16> {
+struct SimilarityL2_avx<16> : SimilarityL2_avx<8>{
     static constexpr int simdwidth = 8;
     static constexpr MetricType metric_type = METRIC_L2;
-
-    const float *y, *yi;
-
-    explicit SimilarityL2_avx (const float * y): y(y) {}
-    __m256 accu8;
-
-    void begin_8 () {
-        accu8 = _mm256_setzero_ps();
-        yi = y;
-    }
-
-    void add_8_components (__m256 x) {
-        __m256 yiv = _mm256_loadu_ps (yi);
-        yi += 8;
-        __m256 tmp = yiv - x;
-        accu8 += tmp * tmp;
-    }
-
-    void add_8_components_2 (__m256 x, __m256 y) {
-        __m256 tmp = y - x;
-        accu8 += tmp * tmp;
-    }
-
-    float result_8 () {
-        __m256 sum = _mm256_hadd_ps(accu8, accu8);
-        __m256 sum2 = _mm256_hadd_ps(sum, sum);
-        // now add the 0th and 4th component
-        return
-            _mm_cvtss_f32 (_mm256_castps256_ps128(sum2)) +
-            _mm_cvtss_f32 (_mm256_extractf128_ps(sum2, 1));
-    }
+    explicit SimilarityL2_avx (const float * y) : SimilarityL2_avx<8>(y) {}
 };
 #endif
 
@@ -596,42 +566,10 @@ struct SimilarityIP_avx<8> {
 
 /* as same as SimilarityIP<8>, let build pass */
 template<>
-struct SimilarityIP_avx<16> {
+struct SimilarityIP_avx<16> : SimilarityIP_avx<8> {
     static constexpr int simdwidth = 8;
     static constexpr MetricType metric_type = METRIC_INNER_PRODUCT;
-
-    const float *y, *yi;
-
-    float accu;
-
-    explicit SimilarityIP_avx (const float * y):
-        y (y) {}
-
-    __m256 accu8;
-
-    void begin_8 () {
-        accu8 = _mm256_setzero_ps();
-        yi = y;
-    }
-
-    void add_8_components (__m256 x) {
-        __m256 yiv = _mm256_loadu_ps (yi);
-        yi += 8;
-        accu8 += yiv * x;
-    }
-
-    void add_8_components_2 (__m256 x1, __m256 x2) {
-        accu8 += x1 * x2;
-    }
-
-    float result_8 () {
-        __m256 sum = _mm256_hadd_ps(accu8, accu8);
-        __m256 sum2 = _mm256_hadd_ps(sum, sum);
-        // now add the 0th and 4th component
-        return
-            _mm_cvtss_f32 (_mm256_castps256_ps128(sum2)) +
-            _mm_cvtss_f32 (_mm256_extractf128_ps(sum2, 1));
-    }
+    explicit SimilarityIP_avx (const float * y) : SimilarityIP_avx<8>(y) {}
 };
 #endif