avx

问题 Given the classic formula for rotating a point in 2D space: cv::Point pt[NPOINTS]; cv::Point rotated[NPOINTS]; float angle = WHATEVER; float cosine = cos(angle); float sine = sin(angle); for (int i = 0; i < NPOINTS; i++) { rotated[i].x = pt[i].x * cosine - pt[i].y * sine; rotated[i].y = pt[i].x * sine + pt[i].y * cosine; } Given NPOINTS is 32 and the arrays are aligned, how would one go about optimising the code for SSE or AVX? Searching around here and elsewhere didn't turn up anything

问题 I am finding difficulties in creating a code for this seemingly easy problem. Given a packed 8 bits integer, substitute one byte with another if present. For instance, I want to substitute 0x06 with 0x01 , so I can do the following with res as the input to find 0x06 : // Bytes to be manipulated res = _mm_set_epi8(0x00, 0x03, 0x02, 0x06, 0x0F, 0x02, 0x02, 0x06, 0x0A, 0x03, 0x02, 0x06, 0x00, 0x00, 0x02, 0x06); // Target value and substitution val = _mm_set1_epi8(0x06); sub = _mm_set1_epi8(0x01)

问题 I found that _mm256_log_ps can't be used with GCC7. Most common suggestions on stackoverflow is to use ICC or leveraging OpenCL SDK. After downloading SDK and extracting RPM file, there are three .so files: __ocl_svml_l9.so, __ocl_svml_e9.so, __ocl_svml_h8.so Can someone teach me how to call _mm256_log_ps with these .so files? Thank you. 回答1: You can use the log function from the Eigen library: #include <Eigen/Core> void foo(float* data, int size) { Eigen::Map<Eigen::ArrayXf> arr(data, size);

问题 I'm using AVX intrinsics, but since for everything other than _mm256 based intrinsics MSVC generates non-vex instructions, I need to compiler the whole source code with /arch:AVX. The rest of the project is compiled with /arch:SSE2, so that it works on older CPUs and I'm manually checking if AVX is available. The source containing AVX code (compiled for AVX) includes a huge library of templates and other stuff, just to have the definitions. Is there a possibility that the compiler/linker

问题 as Paul. R sugguested that there are plenty of resources about SSE2 , AVX on apple developer but I couldn't find it. Could anyone helps me ? BTW, I also looking for the archive of mail-list of altivec. thanks! Intel SSE and AVX Examples and Tutorials 来源： https://stackoverflow.com/questions/22978362/cant-find-materials-about-sse2-altivec-vmx-on-apple-developer

问题 This question already has answers here : Why _umul128 works slower than scalar code for mul128x64x2 function? (1 answer) SIMD signed with unsigned multiplication for 64-bit * 64-bit to 128-bit (2 answers) Is there hardware support for 128bit integers in modern processors? (3 answers) Is there a 128 bit integer in gcc? (3 answers) Closed 3 months ago . I'm trying to implement multiplication of 128 unsigned int on two 64 unsigned integers by Intel AVX. The problem is that non vectorised version

问题 I am trying to learn AVX instructions and while running a basic code I recieve Illegal instruction (core dumped) The code is mentioned below and I am compiling it using g++ -mavx512f 1.cpp What exactly is the problem and how to overcome it? Thank You! #include <immintrin.h> #include<iostream> using namespace std; void add(const float a[], const float b[], float res[], int n) { int i = 0; for(; i < (n&(~0x31)) ; i+=32 ) { __m512 x = _mm512_loadu_ps( &a[i] ); __m512 y = _mm512_loadu_ps( &b[i] )

问题 I am writing a page rank program. I am writing a method for updating the rankings. I have successful got it working with nested for loops and also a threaded version. However I would like to instead use SIMD/AVX. This is the code I would like to change into a SIMD/AVX implementation. #define IDX(a, b) ((a * npages) + b) // 2D matrix indexing for (size_t i = 0; i < npages; i++) { temp[i] = 0.0; for (size_t j = 0; j < npages; j++) { temp[i] += P[j] * matrix_cap[IDX(i,j)]; } } For this code P[]

问题 I'm developing a QT widget that makes use of SIMD instruction sets. I've compiled 3 versions: SSE3, AVX, and AVX2(simdpp allows to switch between them by a single #define). Now, what I want is for my widget to switch automatically between these implementations, according to best supported instruction set. Guide that is provided with simdpp makes use of some makefile magic: CXXFLAGS="" test: main.o test_sse2.o test_sse3.o test_sse4_1.o test_null.o g++ $^ -o test main.o: main.cc g++ main.cc $

问题 I am trying to run SIMD instruction over data types int , float and double . I need multiply, add and load operation. For float and double I successfully managed to make those instructions work: _mm256_add_ps , _mm256_mul_ps and _mm256_load_ps (ending *pd for double). (Direct FMADD operation isn't supported) But for integer I couldn't find a working instruction. All of those showed at intel AVX manual give similar error by GCC 4.7 like "‘_mm256_mul_epu32’ was not declared in this scope". For