set static const values to static constexpr by SteveBronder · Pull Request #2830 · stan-dev/math

SteveBronder · 2022-10-20T16:07:25Z

Summary

This is to fix a bug where some static initialization fiascos can happen when compiling at -O0. I went through and set many of the values from static const to static constexpr. This should only affect things when compiling at -O0 since all the other optimizations levels treat static const values as known at compile time.

Tests

No new tests

Side Effects

Nope. Though I'm away from my desktop atm so these might fail the OpenCL tests as I was not able to test them locally.

Release notes

replaces static const objects with static constexpr when available.

Checklist

Math issue #(issue number)
Copyright holder: Steve Bronder

The copyright holder is typically you or your assignee, such as a university or company. By submitting this pull request, the copyright holder is agreeing to the license the submitted work under the following licenses:
- Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
- Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
the basic tests are passing
- unit tests pass (to run, use: ./runTests.py test/unit)
- header checks pass, (make test-headers)
- dependencies checks pass, (make test-math-dependencies)
- docs build, (make doxygen)
- code passes the built in C++ standards checks (make cpplint)
the code is written in idiomatic C++ and changes are documented in the doxygen
the new changes are tested

…imization still treats them as known as compile time

…to fix/constexpr-constants

…nstants

andrjohns · 2022-12-05T12:24:20Z

@SteveBronder is this ready for review?

andrjohns

Few q's and comments

stan/math/opencl/kernel_generator/multi_result_kernel.hpp

andrjohns · 2023-05-26T08:38:35Z

stan/math/opencl/kernels/add.hpp


 // \cond
-static const std::string add_batch_kernel_code = STRINGIFY(
+static constexpr const char *add_batch_kernel_code = STRINGIFY(


Suggested change

static constexpr const char *add_batch_kernel_code = STRINGIFY(

static constexpr const char* add_batch_kernel_code = STRINGIFY(

For consistency

andrjohns · 2023-05-26T08:38:56Z

stan/math/opencl/kernels/check_symmetric.hpp

 namespace opencl_kernels {
 // \cond
-static const std::string is_symmetric_kernel_code = STRINGIFY(
+static constexpr const char *is_symmetric_kernel_code = STRINGIFY(


Suggested change

static constexpr const char *is_symmetric_kernel_code = STRINGIFY(

static constexpr const char* is_symmetric_kernel_code = STRINGIFY(

andrjohns · 2023-05-26T08:39:18Z

stan/math/opencl/kernels/cumulative_sum.hpp


 // \cond
-static const char *cumulative_sum1_kernel_code = STRINGIFY(
+static constexpr const char *cumulative_sum1_kernel_code = STRINGIFY(


Suggested change

static constexpr const char *cumulative_sum1_kernel_code = STRINGIFY(

static constexpr const char* cumulative_sum1_kernel_code = STRINGIFY(

andrjohns · 2023-05-26T08:39:34Z

stan/math/opencl/kernels/cumulative_sum.hpp


 // \cond
-static const char *cumulative_sum2_kernel_code = STRINGIFY(
+static constexpr const char *cumulative_sum2_kernel_code = STRINGIFY(


Suggested change

static constexpr const char *cumulative_sum2_kernel_code = STRINGIFY(

static constexpr const char* cumulative_sum2_kernel_code = STRINGIFY(

andrjohns · 2023-05-26T08:50:12Z

stan/math/prim/fun/constants.hpp

+static constexpr double LOG_PI
+    = 1.14472988584940017414342735135305871164729481291531157151362;


This is a bit of a departure from how we've stored these constants so far, and not something I'm a huge fan of tbh, is it an essential change here?

Not a blocking comment if there's no alternative, just personal preference

Actually! We can do this directly using boost's constants:

static constexpr double LOG_PI = 2 * boost::math::constants::log_root_two_pi<double>() - LOG_TWO;

andrjohns · 2023-05-26T08:57:31Z

stan/math/prim/fun/log.hpp

+  static constexpr double inf = std::numeric_limits<double>::infinity();
+  static constexpr double nan = std::numeric_limits<double>::quiet_NaN();


This header should just use the NOT_A_NUMBER and INFTY constants directly

andrjohns · 2023-05-26T09:00:19Z

stan/math/prim/fun/log10.hpp

 template <typename V>
 inline std::complex<V> complex_log10(const std::complex<V>& z) {
-  static const double inv_log_10 = 1 / std::log(10);
+  static constexpr double inv_log_10 = 1 / 2.30258509299404568401799145468;


Suggested change

static constexpr double inv_log_10 = 1 / 2.30258509299404568401799145468;

static constexpr double inv_log_10 = 1 / LOG_TEN;

andrjohns · 2023-05-26T09:08:22Z

stan/math/prim/prob/wiener_lpdf.hpp

+  static constexpr double LOG_PI_LOG_WIENER_ERR
+      = LOG_PI + -13.81551055796427410410794872810618524;


Suggested change

static constexpr double LOG_PI_LOG_WIENER_ERR

= LOG_PI + -13.81551055796427410410794872810618524;

static constexpr double LOG_PI_LOG_WIENER_ERR

= LOG_PI - 6 * LOG_TEN;

andrjohns · 2023-05-26T09:09:52Z

stan/math/prim/prob/wiener_lpdf.hpp

+  static constexpr double SQUARE_PI_OVER_TWO
+      = 9.869604401089358618834490999876151135 * 0.5;


Suggested change

static constexpr double SQUARE_PI_OVER_TWO

= 9.869604401089358618834490999876151135 * 0.5;

static constexpr double SQUARE_PI_OVER_TWO = (pi() * pi()) / 2;

andrjohns · 2023-05-26T09:13:01Z

stan/math/prim/fun/constants.hpp

+static constexpr double LOG_SQRT_PI
+    = 0.5723649429247000870717136756765293558236474064576557857568115357;


Suggested change

static constexpr double LOG_SQRT_PI

= 0.5723649429247000870717136756765293558236474064576557857568115357;

static constexpr double LOG_SQRT_PI = LOG_PI / 2;

One more simplification I thought of

…tants

stan-buildbot · 2024-02-16T22:18:51Z

Name	Old Result	New Result	Ratio	Performance change( 1 - new / old )
arma/arma.stan	0.3	0.21	1.43	30.04% faster
low_dim_corr_gauss/low_dim_corr_gauss.stan	0.01	0.01	1.01	0.64% faster
gp_regr/gen_gp_data.stan	0.03	0.03	0.95	-4.99% slower
gp_regr/gp_regr.stan	0.13	0.12	1.06	5.65% faster
sir/sir.stan	86.53	83.2	1.04	3.85% faster
irt_2pl/irt_2pl.stan	4.56	4.19	1.09	8.3% faster
eight_schools/eight_schools.stan	0.06	0.05	1.07	6.72% faster
pkpd/sim_one_comp_mm_elim_abs.stan	0.29	0.26	1.15	12.75% faster
pkpd/one_comp_mm_elim_abs.stan	24.26	18.79	1.29	22.53% faster
garch/garch.stan	0.62	0.49	1.27	21.32% faster
low_dim_gauss_mix/low_dim_gauss_mix.stan	3.13	3.01	1.04	3.79% faster
arK/arK.stan	1.98	2.09	0.95	-5.35% slower
gp_pois_regr/gp_pois_regr.stan	2.76	2.65	1.04	3.95% faster
low_dim_gauss_mix_collapse/low_dim_gauss_mix_collapse.stan	9.96	9.63	1.03	3.28% faster
performance.compilation	196.48	200.74	0.98	-2.17% slower
Mean result: 1.093415632208503

Jenkins Console Log
Blue Ocean
Commit hash: e0626a595a3bddd83ac6d0ec401fba4e39c8c5ea

Machine information

No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 20.04.3 LTS Release: 20.04 Codename: focal

CPU:
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
Address sizes: 46 bits physical, 48 bits virtual
CPU(s): 80
On-line CPU(s) list: 0-79
Thread(s) per core: 2
Core(s) per socket: 20
Socket(s): 2
NUMA node(s): 2
Vendor ID: GenuineIntel
CPU family: 6
Model: 85
Model name: Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz
Stepping: 4
CPU MHz: 3328.328
CPU max MHz: 3700.0000
CPU min MHz: 1000.0000
BogoMIPS: 4800.00
Virtualization: VT-x
L1d cache: 1.3 MiB
L1i cache: 1.3 MiB
L2 cache: 40 MiB
L3 cache: 55 MiB
NUMA node0 CPU(s): 0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78
NUMA node1 CPU(s): 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,53,55,57,59,61,63,65,67,69,71,73,75,77,79
Vulnerability Gather data sampling: Mitigation; Microcode
Vulnerability Itlb multihit: KVM: Mitigation: VMX disabled
Vulnerability L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT vulnerable
Vulnerability Mds: Mitigation; Clear CPU buffers; SMT vulnerable
Vulnerability Meltdown: Mitigation; PTI
Vulnerability Mmio stale data: Mitigation; Clear CPU buffers; SMT vulnerable
Vulnerability Retbleed: Mitigation; IBRS
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; IBRS, IBPB conditional, STIBP conditional, RSB filling, PBRSB-eIBRS Not affected
Vulnerability Srbds: Not affected
Vulnerability Tsx async abort: Mitigation; Clear CPU buffers; SMT vulnerable
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single pti intel_ppin ssbd mba ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts hwp hwp_act_window hwp_epp hwp_pkg_req pku ospke md_clear flush_l1d arch_capabilities

G++:
g++ (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Clang:
clang version 10.0.0-4ubuntu1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

SteveBronder · 2024-02-19T19:45:38Z

@andrjohns thank you for taking this over the finish line!

SteveBronder and others added 25 commits October 20, 2022 12:03

set all static const values to static constexpr so that -O0 level opt…

35e3127

…imization still treats them as known as compile time

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

dbe2429

change static const strings to static constexpr const char*

ca0ca56

change static const strings to static constexpr const char*

9c35e89

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8d95623

update

f200221

Merge branch 'fix/constexpr-constants' of github.com:stan-dev/math in…

dbf86a0

…to fix/constexpr-constants

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

f6b5c52

Fix namespace for bool_constant

b8f8a60

Fix namespace for bool_constant

04c1c98

Merge commit '4d2b936d6686586376bbc8a99ecdf7c0937c251f' into HEAD

9f2af5a

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

e21588e

remove constexpr from opencl double_d type

265f0cf

cpplint fixes

9af3659

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ca927a1

fix weiner_lpdf

0bc2be0

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1d2d4aa

header fix for hypergeometric_2F1

67d3781

Merge branch 'fix/constexpr-constants' of github.com:stan-dev/math in…

9a12c77

…to fix/constexpr-constants

fix index_rev missing }

fa56ba8

Merge commit 'f4c68170c1f1e9bc1284520560204ea9e76c62cd' into HEAD

7fbffe0

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

184978f

ignore whitespace cpplint for opencl kernel

88c4211

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

1a9b1c1

Merge remote-tracking branch 'upstream/develop' into fix/constexpr-co…

bef2174

…nstants

andrjohns and others added 4 commits May 26, 2023 11:26

Merge branch 'develop' into fix/constexpr-constants

7ea0296

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

8779172

Missed cpplint in merge

7f2b34e

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

5ca9e19

andrjohns requested changes May 26, 2023

View reviewed changes

andrjohns reviewed May 26, 2023

View reviewed changes

SteveBronder and others added 19 commits July 20, 2023 16:46

merge to develop

1e503a4

update with simplifications for constant values

12597ce

Merge remote-tracking branch 'origin/develop' into fix/constexpr-cons…

10514e1

…tants

merge conflict

a16df24

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

092c0be

update headers

e9cf9cf

Merge branch 'develop' into fix/constexpr-constants

b527a01

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

ef5fbdc

Fix header tests

d2d4cee

Fix merge breakage

b634978

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

5be6653

Update char * to char*

57cc140

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

87245ad

Cpplint

c7dd4fd

Merge branch 'develop' into fix/constexpr-constants

1cf8c04

const char* updates

952ea3a

[Jenkins] auto-formatting by clang-format version 10.0.0-4ubuntu1

f365972

Temporarily disable problematic test

e9987b6

Revert use of Boost's constants for LOG_PI

44dd969

andrjohns approved these changes Feb 19, 2024

View reviewed changes

andrjohns merged commit c12fff9 into develop Feb 19, 2024

SteveBronder deleted the fix/constexpr-constants branch February 19, 2024 19:45

	static constexpr const char *add_batch_kernel_code = STRINGIFY(
	static constexpr const char* add_batch_kernel_code = STRINGIFY(

	static constexpr const char *is_symmetric_kernel_code = STRINGIFY(
	static constexpr const char* is_symmetric_kernel_code = STRINGIFY(

	static constexpr const char *cumulative_sum1_kernel_code = STRINGIFY(
	static constexpr const char* cumulative_sum1_kernel_code = STRINGIFY(

		static constexpr double LOG_PI
		= 1.14472988584940017414342735135305871164729481291531157151362;

		static constexpr double inf = std::numeric_limits<double>::infinity();
		static constexpr double nan = std::numeric_limits<double>::quiet_NaN();

	static constexpr double inv_log_10 = 1 / 2.30258509299404568401799145468;
	static constexpr double inv_log_10 = 1 / LOG_TEN;

		static constexpr double LOG_PI_LOG_WIENER_ERR
		= LOG_PI + -13.81551055796427410410794872810618524;

		static constexpr double SQUARE_PI_OVER_TWO
		= 9.869604401089358618834490999876151135 * 0.5;

		static constexpr double LOG_SQRT_PI
		= 0.5723649429247000870717136756765293558236474064576557857568115357;

	static constexpr double LOG_SQRT_PI
	= 0.5723649429247000870717136756765293558236474064576557857568115357;
	static constexpr double LOG_SQRT_PI = LOG_PI / 2;

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SteveBronder commented Oct 20, 2022

Summary

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andrjohns commented Dec 5, 2022

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stan-buildbot commented Feb 16, 2024

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