Skip to content

Add stan::json::write_json_value helper functions - #3456

Open
WardBrian wants to merge 7 commits into
developfrom
feat/json-writer-utils
Open

WardBrian wants to merge 7 commits into
developfrom
feat/json-writer-utils

Conversation

@WardBrian

@WardBrian WardBrian commented Oct 29, 2026 •

Copy link
Copy Markdown
Member

Submission Checklist

  • Run unit tests: ./runTests.py src/test/unit
  • Run cpplint: make cpplint
  • Declare copyright holder and open-source license: see below

Summary

Intended for use with stan-dev/stanc3#1747, but also cleans up our existing json writer and includes the fixes from #3434.

Intended Effect

How to Verify

Side Effects

Documentation

Copyright and Licensing

Please list the copyright holder for the work you are submitting (this will be you or your assignee, such as a university or company):

By submitting this pull request, the copyright holder is agreeing to license the submitted work under the following licenses:

@WardBrian

Copy link
Copy Markdown
Member Author

Running the stanc3 branch against this one here

@stan-buildbot

Copy link
Copy Markdown
Contributor
Name Old Result New Result Ratio Performance change( 1 - new / old )
stat_comp_benchmarks/benchmarks/gp_regr/gp_regr.stan 0.22 0.22 1.01 1.18% faster
stat_comp_benchmarks/benchmarks/gp_regr/gen_gp_data.stan 0.06 0.06 1.03 2.67% faster
stat_comp_benchmarks/benchmarks/low_dim_gauss_mix/low_dim_gauss_mix.stan 6.29 6.3 1.0 -0.1% slower
stat_comp_benchmarks/benchmarks/low_dim_corr_gauss/low_dim_corr_gauss.stan 0.02 0.02 1.04 3.51% faster
stat_comp_benchmarks/benchmarks/irt_2pl/irt_2pl.stan 8.24 8.25 1.0 -0.13% slower
stat_comp_benchmarks/benchmarks/gp_pois_regr/gp_pois_regr.stan 4.47 4.41 1.01 1.36% faster
stat_comp_benchmarks/benchmarks/sir/sir.stan 217.93 220.94 0.99 -1.38% slower
stat_comp_benchmarks/benchmarks/garch/garch.stan 0.9 0.88 1.02 2.38% faster
stat_comp_benchmarks/benchmarks/arma/arma.stan 0.61 0.61 1.0 0.47% faster
stat_comp_benchmarks/benchmarks/pkpd/one_comp_mm_elim_abs.stan 42.37 42.45 1.0 -0.2% slower
stat_comp_benchmarks/benchmarks/pkpd/sim_one_comp_mm_elim_abs.stan 0.61 0.59 1.03 2.49% faster
stat_comp_benchmarks/benchmarks/low_dim_gauss_mix_collapse/low_dim_gauss_mix_collapse.stan 20.92 20.74 1.01 0.86% faster
stat_comp_benchmarks/benchmarks/eight_schools/eight_schools.stan 0.11 0.11 0.97 -3.07% slower
stat_comp_benchmarks/benchmarks/arK/arK.stan 3.17 3.18 1.0 -0.14% slower
performance.compilation 364.3 367.28 0.99 -0.82% slower
Mean result: 1.0063771108271142

Jenkins Console Log
Jenkins Build Stages
Commit hash: 1dfac7ebd63e7747b7c9fe5984b0252ad312ebea

Machine information
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:                           43 bits physical, 48 bits virtual
CPU(s):                                  256
On-line CPU(s) list:                     0-255
Thread(s) per core:                      2
Core(s) per socket:                      64
Socket(s):                               2
NUMA node(s):                            2
Vendor ID:                               AuthenticAMD
CPU family:                              23
Model:                                   49
Model name:                              AMD EPYC 7742 64-Core Processor
Stepping:                                0
Frequency boost:                         enabled
CPU MHz:                                 1496.872
CPU max MHz:                             3416.0681
CPU min MHz:                             1500.0000
BogoMIPS:                                4491.85
Virtualization:                          AMD-V
L1d cache:                               4 MiB
L1i cache:                               4 MiB
L2 cache:                                64 MiB
L3 cache:                                512 MiB
NUMA node0 CPU(s):                       0-63,128-191
NUMA node1 CPU(s):                       64-127,192-255
Vulnerability Gather data sampling:      Not affected
Vulnerability Indirect target selection: Not affected
Vulnerability Itlb multihit:             Not affected
Vulnerability L1tf:                      Not affected
Vulnerability Mds:                       Not affected
Vulnerability Meltdown:                  Not affected
Vulnerability Mmio stale data:           Not affected
Vulnerability Old microcode:             Not affected
Vulnerability Reg file data sampling:    Not affected
Vulnerability Retbleed:                  Mitigation; untrained return thunk; SMT enabled with STIBP protection
Vulnerability Spec rstack overflow:      Mitigation; Safe RET
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; Retpolines; IBPB conditional; STIBP always-on; RSB filling; PBRSB-eIBRS Not affected; BHI Not affected
Vulnerability Srbds:                     Not affected
Vulnerability Tsa:                       Not affected
Vulnerability Tsx async abort:           Not affected
Vulnerability Vmscape:                   Mitigation; IBPB before exit to userspace
Flags:                                   fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd amd_ppin arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip rdpid overflow_recov succor smca sev sev_es

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

@WardBrian
WardBrian marked this pull request as ready for review October 30, 2026 15:52
@stan-buildbot

Copy link
Copy Markdown
Contributor
Name Old Result New Result Ratio Performance change( 1 - new / old )
stat_comp_benchmarks/benchmarks/low_dim_gauss_mix_collapse/low_dim_gauss_mix_collapse.stan 9.0 8.64 1.04 4.08% faster
stat_comp_benchmarks/benchmarks/gp_pois_regr/gp_pois_regr.stan 2.4 2.35 1.02 2.11% faster
stat_comp_benchmarks/benchmarks/eight_schools/eight_schools.stan 0.06 0.06 0.98 -2.26% slower
stat_comp_benchmarks/benchmarks/irt_2pl/irt_2pl.stan 4.7 4.64 1.01 1.25% faster
stat_comp_benchmarks/benchmarks/garch/garch.stan 0.48 0.48 1.0 0.04% faster
stat_comp_benchmarks/benchmarks/low_dim_gauss_mix/low_dim_gauss_mix.stan 2.89 2.85 1.01 1.36% faster
stat_comp_benchmarks/benchmarks/pkpd/sim_one_comp_mm_elim_abs.stan 0.24 0.24 1.02 1.87% faster
stat_comp_benchmarks/benchmarks/pkpd/one_comp_mm_elim_abs.stan 19.22 18.88 1.02 1.75% faster
stat_comp_benchmarks/benchmarks/gp_regr/gen_gp_data.stan 0.02 0.02 1.01 0.62% faster
stat_comp_benchmarks/benchmarks/gp_regr/gp_regr.stan 0.11 0.11 1.02 1.61% faster
stat_comp_benchmarks/benchmarks/sir/sir.stan 89.54 87.17 1.03 2.65% faster
stat_comp_benchmarks/benchmarks/arK/arK.stan 1.68 1.62 1.04 3.69% faster
stat_comp_benchmarks/benchmarks/low_dim_corr_gauss/low_dim_corr_gauss.stan 0.01 0.01 1.0 -0.13% slower
stat_comp_benchmarks/benchmarks/arma/arma.stan 0.31 0.32 0.96 -3.64% slower
performance.compilation 242.8 228.48 1.06 5.9% faster
Mean result: 1.0146796525232535

Jenkins Console Log
Jenkins Build Stages
Commit hash: e7cab1646d71f360d212c6aecb8537bca67ebe6f

Machine information
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 6248 CPU @ 2.50GHz
Stepping:                                7
CPU MHz:                                 999.590
CPU max MHz:                             3900.0000
CPU min MHz:                             1000.0000
BogoMIPS:                                5000.00
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 Indirect target selection: Mitigation; Aligned branch/return thunks
Vulnerability Itlb multihit:             KVM: Mitigation: Split huge pages
Vulnerability L1tf:                      Not affected
Vulnerability Mds:                       Not affected
Vulnerability Meltdown:                  Not affected
Vulnerability Mmio stale data:           Mitigation; Clear CPU buffers; SMT vulnerable
Vulnerability Old microcode:             Not affected
Vulnerability Reg file data sampling:    Not affected
Vulnerability Retbleed:                  Mitigation; Enhanced IBRS
Vulnerability Spec rstack overflow:      Not affected
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; Enhanced / Automatic IBRS; IBPB conditional; PBRSB-eIBRS SW sequence; BHI SW loop, KVM SW loop
Vulnerability Srbds:                     Not affected
Vulnerability Tsa:                       Not affected
Vulnerability Tsx async abort:           Mitigation; TSX disabled
Vulnerability Vmscape:                   Mitigation; IBPB before exit to userspace
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 intel_ppin ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid 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 vnmi pku ospke avx512_vnni 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

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants