c++ - AVX segmentation fault on linux -

-

i trying run code , says segmentation fault when run it. compiles good. here code. (it works fine on windows).

#include<iostream> #include<vector> #include<immintrin.h>  const int size = 1000000;  std::vector<float>a(size); std::vector<float>b(size); std::vector<float>c(size);  void bar(int i){     const float = 2.0f;     __m256 _a = _mm256_broadcast_ss(&a);     __m256 _a = _mm256_load_ps(&a[0] + i*8);     __m256 _b = _mm256_load_ps(&b[0] + i*8);     __m256 _c = _mm256_add_ps(_b, _mm256_mul_ps(_a,_a));     _mm256_store_ps(&c[0] + i*8, _c); }   int main(){     std::fill(a.begin(), a.end(), 1.0f);     std::fill(b.begin(), b.end(), 2.0f);     bar(0);      return 0; }

compiling: g++ -mavx t2.cpp -o t2

it's exiting when hit first avx instruction. want review code.

here gdb trace

(gdb) run program received signal sigsegv, segmentation fault. 0x0000000000400aea in bar(int) () missing separate debuginfos, use: debuginfo-install glibc-2.17-78.el7.x86_64 libgcc-4.8.3-9.el7.x86_64 libstdc++-4.8.3-9.el7.x86_64 (gdb) bt #0  0x0000000000400aea in bar(int) () #1  0x0000000000400b95 in main () (gdb)

it data alignment issue. _mm256_load_ps requires 256-bit (32-bytes) aligned memory. default allocator std::vector doesn't meet requirement. you'll need supply aligned allocator or use instruction less stringent alignment requirement (such _mm256_loadu_ps).


Comments

Post a Comment

Popular posts from this blog

javascript - Chart.js (Radar Chart) different scaleLineColor for each scaleLine -

-
Image
i try , create radar chart using chart.js has various colours each scaleline, or coloured between scalelines. wondering if possible? from: to: i have working graph, though there doesn't seem method change individual scale lines. kind regards leigh you can extend radar chart type this, so chart.types.radar.extend({ name: "radaralt", initialize: function (data) { chart.types.radar.prototype.initialize.apply(this, arguments); var originalscaledraw = this.scale.draw; var ctx = this.chart.ctx; this.scale.draw = function () { var linewidth = this.linewidth; // bypasses line drawing in originalscaledraw this.linewidth = linewidth; originalscaledraw.apply(this, arguments); ctx.linewidth = this.linewidth; var scale = this; // draw chart.helpers.each(scale.ylabels, function (label, index) { // color of ...
Read more

apache - Error with PHP mail(): Multiple or malformed newlines found in additional_header -

-
suddenly have started receiving above error without changes having been made script. host 1and1 (i know...) the script still works fine on different server, , suspicion there must have been server config change has lead this, although hosts plead ignorance. there's no information on above error @ in google can find - have ideas? server running apache if helps. had similar problem. came out of blue. no php code changed. what changed: php upgraded 5.5.25-1 5.5.26. a security risk in php mail() function has been fixed , newlines in additional_headers allowed no more. because newlines mean: starts email message (and surely don't want inject newlines through headers followed evil message). what have worked fine, e.g. having newlines after headers or passing whole message additional_headers , function no more. solution : sanitize headers. no multiple newlines in additional_headers argument. these count "multiple or malformed newlines":...
Read more

android - Go back to previous fragment -

-
btw second fragment. appear once press button in first fragment. in fragment, if press button on phone, go previous fragment. need guys. in advance. public class listalldoctorfragment extends fragment { button close; @nullable @override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) { view view = inflater.inflate(r.layout.listalldoctor, container,false); close = (button) view.findviewbyid(r.id.button); close.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { android.app.fragmentmanager fm = getfragmentmanager(); fragmenttransaction ft = fm.begintransaction(); shit f2 = new shit(); ft.add(r.id.content_frame, f2); ft.addtobackstack(null); ft.commit(); } }); return view; } } assuming want g...
Read more