sudden6 / m-queens

Very fast n-queens solver with OpenMP support

m-queens

Multi-queens, a very fast solver for the general eight queens problem with OpenMP support.

Based on code from https://rosettacode.org/wiki/N-queens_problem#C but much more optimized.

If you find a way to make the code even faster, please let me know. Also feel free to open a Pull Request to add your own benchmarks.

Benchmarks

Single-Thread

Compiled with gcc-7 -o m-queens.bin main.c -O2 -march=native -mtune=native -std=c99 and run with ./m-queens 18.

CPU	N	Time to solve
Intel(R) Core(TM) i7-4600M CPU@ 3.5 GHz (single core)	18	129.56s

Multi-Thread

Compiled with gcc-7 -o m-queens.bin main.c -O2 -march=native -mtune=native -std=c99 -fopenmp and run with ./m-queens 18.

CPU	Cores (real/virtual)	N	Time to solve	Speedup from Single-Thread
Intel(R) Core(TM) i7-4600M CPU@ 3.4 GHz (all cores)	2/4	18	52.56s	2.46

Future Improvements

Use the optimized placement mentioned in https://github.com/preusser/q27 to reduce symmetries.

probably very hard to do with the current implementation

Use OpenCL to make use of GPUs

Work in progress in the sieves, split2_debug and ringbuffer branches.

m-queens's Issues

error: variadic macros not supported in OpenCL

I'm trying out the binaries in https://github.com/sudden6/m-queens/releases/tag/m-queens-ocl-v0.3

Is it possible to recompile without the printf() without loss of functionality?

Output:

m-queens2.exe -m ocl -s 18

Platform version: OpenCL 3.0 CUDA 12.1.109
Device:           NVIDIA GeForce RTX 4090
Device version:   OpenCL 3.0 CUDA
OpenCL 3.x supported
Device events:    0
Device memory:    24563MB
Allocation limit: 6140MB

Aligning to SUM_REDUCTION_FACTOR: 50331648
OPTIONS: -cl-std=CL2.0 -DBOARDSIZE=18 -DGPU_DEPTH=11 -DWORKSPACE_SIZE=50331648 -DWORKGROUP_SIZE=64 -DSUM_REDUCTION_FACTOR=8192 -DDEBUG_PRINT=0
1 error generated.
1 error generated.
OpenCL build log:
<kernel>:25:16: error: variadic macros not supported in OpenCL
#define printf(...)
               ^

program.build failed: -11
Solver init failed

---

On a side-note, I'm trying to figure out how to compile this project on Windows. I'm not sure what to change "BOINC_DIR = ../../static_boinc" in the Makefile to, since I couldn't find a static_boinc directory anywhere.

Rdna 3

hey! I've just tested the v0.3 version on Radeon 7900 xtx and here's the result:

Platform name: AMD Accelerated Parallel Processing
Platform version: OpenCL 2.1 AMD-APP (3516.0)
Device: gfx1100
Device version: OpenCL 2.0 AMD-APP (3516.0)
OpenCL 2.x supported
Device events: 1024
Device memory: 24560MB
Allocation limit: 24560MB

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
PASS N 5, Solutions 10, Expected 10, Time 0.896884, Solutions/s 11.1

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 6, Solutions 32, Expected 4, Time 15.170354, Solutions/s 2.11

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 7, Solutions 74, Expected 40, Time 12.819202, Solutions/s 5.77

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
PASS N 8, Solutions 92, Expected 92, Time 0.955100, Solutions/s 96.3

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
PASS N 9, Solutions 352, Expected 352, Time 0.831018, Solutions/s 424

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 10, Solutions 364, Expected 724, Time 12.739464, Solutions/s 28.6

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 11, Solutions 536, Expected 2680, Time 12.865021, Solutions/s 41.7

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 12, Solutions 756, Expected 14200, Time 12.939747, Solutions/s 58.4

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 13, Solutions 1030, Expected 73712, Time 12.558832, Solutions/s 82

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 14, Solutions 1364, Expected 365596, Time 12.777974, Solutions/s 107

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 15, Solutions 13980, Expected 2279184, Time 12.678566, Solutions/s 1.1e+03

Launching reduction sum kernels, count: 6144, workspace_size: 50331648, SUM_REDUCTION_FACTOR: 8192
FAIL N 16, Solutions 141812, Expected 14772512, Time 12.827804, Solutions/s 1.11e+04

there're errors and I know this card isn't officially supported, but maybe there's something evident from the pattern? I can't probably fix it by myself, but I can help test it, provide logs etc..

Latest Version of GPU Software not downloading ATI units from BOINC (RX 580)

Hello,

Recently I acquired a XFX RX 580 since it was cheap and I wanted to help push the yoyo mqueens project to completion. I imaged a PC with a fresh Win 10 home install yesterday (02/04) and did the update dance. I got BOINC installed, downloaded the compiled 0.3 package, and followed the readme to drop the exe along with the appconfig and libOpenCL in the proper ProgramData folder, as my install follows yours. However, it does not seem to work correctly.

When I look in the BOINC logs, it looks like it is asking for both CPU and ATI tasks. No issue. However, it will only download CPU workunits and not the ATI ones. It says it requests, then gets 0 units. Since yoyo@home has never run GPU projects in the past, there is no way in the project itself to force the GPU.

However, when I run 0.2 doing the same steps, it works perfectly fine. It no longer downloads CPU units which is fine, and the GPU is kept fed. The tasks are also carrying to completion without issue.

Not exactly sure what is happening with 0.3 since the appconfig is basically the same between the 2. Please let me know what else you would need from me. I assume I must be doing something wrong. I would like to try and use the latest version of the software if possible just to see if it runs faster for me.

i get Not an OpenCL 2.x device, version: OpenCL 3.0 CUDA Failed to create solver

My gpu reports
OpenCL: NVIDIA GPU 0: NVIDIA GeForce GTX 1650 (driver version 466.11, device version OpenCL 3.0 CUDA, 4096MB, 3327MB available, 2849 GFLOPS peak)

RX 6600 XT

Hello,
how about RX 6600 XT?

error log:
<stderr_out>
<core_client_version>7.16.20</core_client_version>

(unknown error) - exit code 3221225477 (0xc0000005) Platform name: AMD Accelerated Parallel Processing Platform version: OpenCL 2.1 AMD-APP (3354.13) Device: gfx1032 Device version: OpenCL 2.0 AMD-APP (3354.13) Device memory: 8176MB OPTIONS: -cl-std=CL2.0 -DBOARDSIZE=27 -DGPU_DEPTH=11 -DWORKSPACE_SIZE=20971520 -DWORKGROUP_SIZE=64 Unhandled Exception Detected... - Unhandled Exception Record - Reason: Access Violation (0xc0000005) at address 0x00007ff97d4c1f4c read attempt to address 0x00000000 Engaging BOINC Windows Runtime Debugger... ******************** BOINC Windows Runtime Debugger Version 7.16.14 Dump Timestamp : 02/17/22 03:55:59 Install Directory : C:\Program Files\BOINC\ Data Directory : C:\ProgramData\BOINC Project Symstore : LoadLibraryA( C:\ProgramData\BOINC\dbghelp.dll ): GetLastError = 126 Loaded Library : dbghelp.dll LoadLibraryA( C:\ProgramData\BOINC\symsrv.dll ): GetLastError = 126 LoadLibraryA( symsrv.dll ): GetLastError = 126 LoadLibraryA( C:\ProgramData\BOINC\srcsrv.dll ): GetLastError = 126 LoadLibraryA( srcsrv.dll ): GetLastError = 126 LoadLibraryA( C:\ProgramData\BOINC\version.dll ): GetLastError = 126 Loaded Library : version.dll Debugger Engine : 4.0.5.0 Symbol Search Path: C:\ProgramData\BOINC\slots\0;C:\ProgramData\BOINC\projects\www.rechenkraft.net_yoyo Get Product Name Failed. ModLoad: 0000000040000000 000000000019d000 C:\ProgramData\BOINC\projects\www.rechenkraft.net_yoyo\m-queens2-boinc-ocl.exe (1.0.0.0) (-nosymbols- Symbols Loaded) File Version : 1, 0, 0, 0 Company Name : MingW-W64 Project. All rights reserved. Product Name : Product Version : 1, 0, 0, 0 ModLoad: 00000000d1070000 00000000001f5000 C:\Windows\SYSTEM32\ntdll.dll (10.0.19041.1466) (-exported- Symbols Loaded) File Version : 10.0.19041.1466 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1466 ModLoad: 00000000d0470000 00000000000be000 C:\Windows\System32\KERNEL32.DLL (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1503 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1503 ModLoad: 00000000ce7b0000 00000000002c8000 C:\Windows\System32\KERNELBASE.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1503 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1503 ModLoad: 00000000cfb60000 00000000000ae000 C:\Windows\System32\ADVAPI32.dll (10.0.19041.1466) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000d0e60000 000000000009e000 C:\Windows\System32\msvcrt.dll (7.0.19041.546) (-exported- Symbols Loaded) File Version : 7.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 7.0.19041.546 ModLoad: 00000000d09e0000 000000000009c000 C:\Windows\System32\sechost.dll (10.0.19041.1466) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000d0f00000 0000000000125000 C:\Windows\System32\RPCRT4.dll (10.0.19041.1466) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000cf0c0000 0000000000744000 C:\Windows\System32\SHELL32.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.964 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.964 ModLoad: 00000000ceb20000 000000000009d000 C:\Windows\System32\msvcp_win.dll (10.0.19041.789) (-exported- Symbols Loaded) File Version : 10.0.19041.789 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.789 ModLoad: 00000000cee00000 0000000000100000 C:\Windows\System32\ucrtbase.dll (10.0.19041.789) (-exported- Symbols Loaded) File Version : 10.0.19041.789 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.789 ModLoad: 00000000d0590000 00000000001a0000 C:\Windows\System32\USER32.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000ce780000 0000000000022000 C:\Windows\System32\win32u.dll (10.0.19041.1526) (-exported- Symbols Loaded) File Version : 10.0.19041.1526 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1526 ModLoad: 00000000cfb30000 000000000002b000 C:\Windows\System32\GDI32.dll (10.0.19041.1202) (-exported- Symbols Loaded) File Version : 10.0.19041.1202 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1202 ModLoad: 00000000cefb0000 000000000010d000 C:\Windows\System32\gdi32full.dll (10.0.19041.1466) (-exported- Symbols Loaded) File Version : 10.0.19041.1466 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1466 ModLoad: 0000000061d00000 0000000000012000 C:\ProgramData\BOINC\projects\www.rechenkraft.net_yoyo\libOpenCL.dll (2.2.6.0) (-exported- Symbols Loaded) File Version : 2.2.6.0 Company Name : Khronos Group Product Name : Khronos OpenCL ICD Loader Product Version : ModLoad: 00000000ced20000 000000000004e000 C:\Windows\System32\CFGMGR32.dll (10.0.19041.1151) (-exported- Symbols Loaded) File Version : 10.0.19041.1151 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1151 ModLoad: 00000000cfa00000 000000000012a000 C:\Windows\System32\ole32.dll (10.0.19041.1202) (-exported- Symbols Loaded) File Version : 10.0.19041.1320 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1320 ModLoad: 00000000d0a80000 0000000000355000 C:\Windows\System32\combase.dll (10.0.19041.1348) (-exported- Symbols Loaded) File Version : 10.0.19041.1320 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1320 ModLoad: 00000000d0900000 0000000000030000 C:\Windows\System32\IMM32.DLL (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 000000007fac0000 00000000040fa000 C:\Windows\System32\DriverStore\FileRepository\u0376255.inf_amd64_b67dbc7531b4ea7c\B376137\amdocl64.dll (10.0.3354.13) (-exported- Symbols Loaded) File Version : 10.0.3354.13 Company Name : Advanced Micro Devices Inc. Product Name : OpenCL 2.0 AMD-APP (3354.13) Product Version : 10.0.3354.13 ModLoad: 00000000b5a80000 0000000000125000 C:\Windows\SYSTEM32\OPENGL32.dll (10.0.19041.1081) (-exported- Symbols Loaded) File Version : 10.0.19041.1081 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1081 ModLoad: 00000000b6a20000 000000000002c000 C:\Windows\SYSTEM32\GLU32.dll (10.0.19041.1081) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000cff20000 0000000000472000 C:\Windows\System32\SETUPAPI.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000cea80000 0000000000027000 C:\Windows\System32\bcrypt.dll (10.0.19041.1023) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000d0530000 0000000000055000 C:\Windows\System32\SHLWAPI.dll (10.0.19041.1023) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000cc490000 000000000002f000 C:\Windows\SYSTEM32\dwmapi.dll (10.0.19041.746) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000ce4b0000 0000000000034000 C:\Windows\SYSTEM32\DEVOBJ.dll (10.0.19041.1151) (-exported- Symbols Loaded) File Version : 10.0.19041.1151 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1151 ModLoad: 00000000ceab0000 0000000000069000 C:\Windows\System32\WINTRUST.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1503 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1503 ModLoad: 00000000cebc0000 0000000000156000 C:\Windows\System32\CRYPT32.dll (10.0.19041.1320) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000ce2f0000 0000000000012000 C:\Windows\SYSTEM32\MSASN1.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 000000007a5b0000 000000000550b000 C:\Windows\System32\DriverStore\FileRepository\u0376255.inf_amd64_b67dbc7531b4ea7c\B376137\amd_comgr.dll (-exported- Symbols Loaded) ModLoad: 00000000d03a0000 00000000000cd000 C:\Windows\System32\OLEAUT32.dll (10.0.19041.985) (-exported- Symbols Loaded) File Version : 10.0.19041.985 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.985 ModLoad: 00000000c55c0000 000000000000a000 C:\Windows\SYSTEM32\VERSION.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 00000000b6a50000 0000000000067000 C:\Windows\SYSTEM32\IntelOpenCL64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel(R) OpenCL(TM) SDK Product Version : 20.19.15.4531 ModLoad: 00000000a9030000 00000000001c2000 C:\Program Files (x86)\Common Files\Intel\OpenCL\bin\x64\intelocl64.dll (5.2.0.10094) (-exported- Symbols Loaded) File Version : 5.2.0.10094 Company Name : Intel Corporation Product Name : Intel(R) SDK for OpenCL* Applications Product Version : 5.2.0.10094 ModLoad: 00000000aa840000 000000000009d000 C:\Program Files (x86)\Common Files\Intel\OpenCL\bin\x64\task_executor64.dll (5.2.0.10094) (-exported- Symbols Loaded) File Version : 5.2.0.10094 Company Name : Intel Corporation Product Name : Intel(R) OpenCL(TM) SDK Product Version : 5.2.0.10094 ModLoad: 000000009ab60000 00000000000d8000 C:\Program Files (x86)\Common Files\Intel\OpenCL\bin\x64\cpu_device64.dll (5.2.0.10094) (-exported- Symbols Loaded) File Version : 5.2.0.10094 Company Name : Intel Corporation Product Name : Intel(R) OpenCL(TM) SDK Product Version : 5.2.0.10094 ModLoad: 000000008cc50000 00000000004c1000 C:\Windows\SYSTEM32\igdrcl64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel HD Graphics Drivers for Windows(R) Product Version : 20.19.15.4531 ModLoad: 00000000cd2d0000 00000000000f4000 C:\Windows\SYSTEM32\dxgi.dll (10.0.19041.1266) (-exported- Symbols Loaded) File Version : 10.0.19041.1266 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1266 ModLoad: 00000000cd020000 0000000000012000 C:\Windows\SYSTEM32\kernel.appcore.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 00000000cc780000 0000000000794000 C:\Windows\SYSTEM32\windows.storage.dll (10.0.19041.1503) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000ce100000 000000000002e000 C:\Windows\SYSTEM32\Wldp.dll (10.0.19041.1320) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000cf820000 00000000000ad000 C:\Windows\System32\SHCORE.dll (10.0.19041.1387) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000c06f0000 000000000003b000 C:\Windows\SYSTEM32\dxcore.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 00000000bc660000 0000000000043000 C:\Windows\SYSTEM32\igdfcl64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel HD Graphics Drivers for Windows(R) Product Version : 20.19.15.4531 ModLoad: 000000008c4f0000 0000000000577000 C:\Windows\SYSTEM32\igdmcl64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel HD Graphics Drivers for Windows(R) Product Version : 20.19.15.4531 ModLoad: 00000000c7f30000 00000000001e4000 C:\Windows\SYSTEM32\dbghelp.dll (10.0.19041.867) (-exported- Symbols Loaded) File Version : 10.0.19041.867 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.867 ModLoad: 00000000b0070000 000000000006d000 C:\Windows\SYSTEM32\igdbcl64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel HD Graphics Drivers for Windows(R) Product Version : 20.19.15.4531 ModLoad: 00000000bece0000 0000000000a40000 C:\Windows\SYSTEM32\igdusc64.dll (20.19.15.4531) (-exported- Symbols Loaded) File Version : 20.19.15.4531 Company Name : Intel Corporation Product Name : Intel HD Graphics Drivers for Windows(R) Product Version : 20.19.15.4531 ModLoad: 00000000ce050000 0000000000018000 C:\Windows\SYSTEM32\CRYPTSP.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 00000000cd7e0000 0000000000034000 C:\Windows\system32\rsaenh.dll (10.0.19041.1052) (-exported- Symbols Loaded) File Version : 10.0.19041.1 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1 ModLoad: 00000000ce070000 000000000000c000 C:\Windows\SYSTEM32\CRYPTBASE.dll (10.0.19041.546) (-exported- Symbols Loaded) File Version : 10.0.19041.546 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.546 ModLoad: 00000000ced70000 0000000000082000 C:\Windows\System32\bcryptPrimitives.dll (10.0.19041.1415) (-exported- Symbols Loaded) File Version : 10.0.19041.1415 (WinBuild.160101.0800) Company Name : Microsoft Corporation Product Name : Microsoft® Windows® Operating System Product Version : 10.0.19041.1415

Survey Question on the For loop in source file /main.c line 136

Hello Sir/ Madam
We are from a research group at Iowa State University, USA. We want to do a survey on Github developers on the methods they used for paralleling their code. To do the survey, We want to ask three questions about this for loop:

1. Can you briefly explain the purpose of using pragma for this case? If the pragma contained reduction and private clauses, can you briefly mention the purposes of variables in those clauses?

2. How much confidence do you have about the correctness of this implementation? You can choose from 1-5 with 1 as the lowest confidence score and 5 as the highest confidence score.

3. (Optional) Do you actually run (interpret the code with compilation and pass input/get output) the code and see the optimization of parallelization? Yes/No

• If yes, can you provide the information of what are the input and expected output of this program (the input that caused the program to run through this for-loop).

The for loop is from line 136 of file https:/github.com/sudden6/m-queens/blob/master//main.c
Here is a part of the code:

omp parallel for reduction(+ : num) schedule(dynamic)
for (uint_fast32_t cnt = 0; cnt < start_level3_cnt; cnt++)
{
uint_fast32_t cols[29];
uint_fast32_t posibs[29];
uint_fast32_t diagl[29];
uint_fast32_t diagr[29];
int8_t rest[29];
int_fast16_t d = 1;
cols[d] = start_level3[cnt][0];
diagl[d] = start_level3[cnt][1];
diagr[d] = start_level3[cnt][2];
rest[d] = ((n - 2) - 3) - 1;
uint_fast32_t posib = (cols[d] | diagl[d]) | diagr[d];
diagl[d] <<= 1;
diagr[d] >>= 1;
while (d > 0)
{
int8_t l_rest = rest[d];
while (po

Sincerely thanks