Possibly test HiGHS on RISC-V hardware

[orlitzky]

As requested! But keep in mind that the difference was only important with GCC at -O2, or with clang, and on ARM64 or RISC-V hardware.

edge_disjoint_spanning_trees.lp.txt
edge_disjoint_spanning_trees.mps.txt

[jajhall]

Sure. Are these compiler and architecture combinations that we support OK @galabovaa?

[jajhall]

HiGHS solves the .lp (MPS) file in 2.09 (0.92) seconds, with a clearly different algorithmic path. Seeing that they correspond to a feasibility problem, different solutions are very likely.

Different machine, but undoubtedly rather faster than GLPK

[galabovaa]

We have GCC and -O2 tested, as well as clang on ARM but we have not yet tested HiGHS on RISC-V hardware

[orlitzky]

jajhall changed the title Example MIP from SageMath Possibly test HiGHS on RISC-V hardware

I'm in the middle of it :P

[orlitzky]

Test project /home/mjo/src/HiGHS.git/build
        Start   1: capi_unit_tests
  1/150 Test   #1: capi_unit_tests ........................   Passed    0.18 sec
        Start   2: unit-test-build
  2/150 Test   #2: unit-test-build ........................   Passed    0.76 sec
        Start   3: unit_tests_all
  3/150 Test   #3: unit_tests_all .........................***Failed   43.85 sec
        Start   4: 25fv47--presolve=off
  4/150 Test   #4: 25fv47--presolve=off ...................***Failed  Required regular expression not found. Regex=[Simplex   iterations: 3149
Objective value     :  5.5018458883
]  0.93 sec
        Start   5: 25fv47--presolve=on
  5/150 Test   #5: 25fv47--presolve=on ....................   Passed    0.80 sec
        Start   6: 25fv47--random_seed=1
  6/150 Test   #6: 25fv47--random_seed=1 ..................   Passed    0.85 sec
        Start   7: 25fv47--random_seed=2
  7/150 Test   #7: 25fv47--random_seed=2 ..................   Passed    0.80 sec
        Start   8: 25fv47--random_seed=3
  8/150 Test   #8: 25fv47--random_seed=3 ..................   Passed    0.85 sec
        Start   9: 80bau3b--presolve=off
  9/150 Test   #9: 80bau3b--presolve=off ..................***Failed  Required regular expression not found. Regex=[Simplex   iterations: 3686
Objective value     :  9.8722419241
]  0.85 sec
        Start  10: 80bau3b--presolve=on
 10/150 Test  #10: 80bau3b--presolve=on ...................   Passed    0.87 sec
        Start  11: 80bau3b--random_seed=1
 11/150 Test  #11: 80bau3b--random_seed=1 .................   Passed    0.88 sec
        Start  12: 80bau3b--random_seed=2
 12/150 Test  #12: 80bau3b--random_seed=2 .................   Passed    0.93 sec
        Start  13: 80bau3b--random_seed=3
 13/150 Test  #13: 80bau3b--random_seed=3 .................   Passed    0.87 sec
        Start  14: adlittle--presolve=off
 14/150 Test  #14: adlittle--presolve=off .................   Passed    0.04 sec
        Start  15: adlittle--presolve=on
 15/150 Test  #15: adlittle--presolve=on ..................   Passed    0.05 sec
        Start  16: adlittle--random_seed=1
 16/150 Test  #16: adlittle--random_seed=1 ................   Passed    0.05 sec
        Start  17: adlittle--random_seed=2
 17/150 Test  #17: adlittle--random_seed=2 ................   Passed    0.05 sec
        Start  18: adlittle--random_seed=3
 18/150 Test  #18: adlittle--random_seed=3 ................   Passed    0.05 sec
        Start  19: afiro--presolve=off
 19/150 Test  #19: afiro--presolve=off ....................   Passed    0.03 sec
        Start  20: afiro--presolve=on
 20/150 Test  #20: afiro--presolve=on .....................   Passed    0.03 sec
        Start  21: afiro--random_seed=1
 21/150 Test  #21: afiro--random_seed=1 ...................   Passed    0.03 sec
        Start  22: afiro--random_seed=2
 22/150 Test  #22: afiro--random_seed=2 ...................   Passed    0.03 sec
        Start  23: afiro--random_seed=3
 23/150 Test  #23: afiro--random_seed=3 ...................   Passed    0.03 sec
        Start  24: etamacro--presolve=off
 24/150 Test  #24: etamacro--presolve=off .................***Failed  Required regular expression not found. Regex=[Simplex   iterations: 532
Objective value     : -7.5571523330
]  0.11 sec
        Start  25: etamacro--presolve=on
 25/150 Test  #25: etamacro--presolve=on ..................   Passed    0.12 sec
        Start  26: etamacro--random_seed=1
 26/150 Test  #26: etamacro--random_seed=1 ................   Passed    0.12 sec
        Start  27: etamacro--random_seed=2
 27/150 Test  #27: etamacro--random_seed=2 ................   Passed    0.12 sec
        Start  28: etamacro--random_seed=3
 28/150 Test  #28: etamacro--random_seed=3 ................   Passed    0.13 sec
        Start  29: greenbea--presolve=off
 29/150 Test  #29: greenbea--presolve=off .................***Failed  Required regular expression not found. Regex=[Simplex   iterations: 5109
Objective value     : -7.2555248130
]  3.24 sec
        Start  30: greenbea--presolve=on
 30/150 Test  #30: greenbea--presolve=on ..................   Passed    1.32 sec
        Start  31: greenbea--random_seed=1
 31/150 Test  #31: greenbea--random_seed=1 ................   Passed    1.24 sec
        Start  32: greenbea--random_seed=2
 32/150 Test  #32: greenbea--random_seed=2 ................   Passed    1.38 sec
        Start  33: greenbea--random_seed=3
 33/150 Test  #33: greenbea--random_seed=3 ................   Passed    1.33 sec
        Start  34: shell--presolve=off
 34/150 Test  #34: shell--presolve=off ....................   Passed    0.10 sec
        Start  35: shell--presolve=on
 35/150 Test  #35: shell--presolve=on .....................   Passed    0.15 sec
        Start  36: shell--random_seed=1
 36/150 Test  #36: shell--random_seed=1 ...................   Passed    0.15 sec
        Start  37: shell--random_seed=2
 37/150 Test  #37: shell--random_seed=2 ...................   Passed    0.15 sec
        Start  38: shell--random_seed=3
 38/150 Test  #38: shell--random_seed=3 ...................   Passed    0.15 sec
        Start  39: stair--presolve=off
 39/150 Test  #39: stair--presolve=off ....................***Failed  Required regular expression not found. Regex=[Simplex   iterations: 529
Objective value     : -2.5126695119
]  0.16 sec
        Start  40: stair--presolve=on
 40/150 Test  #40: stair--presolve=on .....................   Passed    0.15 sec
        Start  41: stair--random_seed=1
 41/150 Test  #41: stair--random_seed=1 ...................   Passed    0.15 sec
        Start  42: stair--random_seed=2
 42/150 Test  #42: stair--random_seed=2 ...................   Passed    0.15 sec
        Start  43: stair--random_seed=3
 43/150 Test  #43: stair--random_seed=3 ...................   Passed    0.15 sec
        Start  44: standata--presolve=off
 44/150 Test  #44: standata--presolve=off .................   Passed    0.06 sec
        Start  45: standata--presolve=on
 45/150 Test  #45: standata--presolve=on ..................   Passed    0.09 sec
        Start  46: standata--random_seed=1
 46/150 Test  #46: standata--random_seed=1 ................   Passed    0.09 sec
        Start  47: standata--random_seed=2
 47/150 Test  #47: standata--random_seed=2 ................   Passed    0.09 sec
        Start  48: standata--random_seed=3
 48/150 Test  #48: standata--random_seed=3 ................   Passed    0.09 sec
        Start  49: standgub--presolve=off
 49/150 Test  #49: standgub--presolve=off .................   Passed    0.07 sec
        Start  50: standgub--presolve=on
 50/150 Test  #50: standgub--presolve=on ..................   Passed    0.09 sec
        Start  51: standgub--random_seed=1
 51/150 Test  #51: standgub--random_seed=1 ................   Passed    0.10 sec
        Start  52: standgub--random_seed=2
 52/150 Test  #52: standgub--random_seed=2 ................   Passed    0.10 sec
        Start  53: standgub--random_seed=3
 53/150 Test  #53: standgub--random_seed=3 ................   Passed    0.09 sec
        Start  54: standmps--presolve=off
 54/150 Test  #54: standmps--presolve=off .................   Passed    0.08 sec
        Start  55: standmps--presolve=on
 55/150 Test  #55: standmps--presolve=on ..................   Passed    0.11 sec
        Start  56: standmps--random_seed=1
 56/150 Test  #56: standmps--random_seed=1 ................   Passed    0.11 sec
        Start  57: standmps--random_seed=2
 57/150 Test  #57: standmps--random_seed=2 ................   Passed    0.11 sec
        Start  58: standmps--random_seed=3
 58/150 Test  #58: standmps--random_seed=3 ................   Passed    0.11 sec
        Start  59: bgetam--presolve=off
 59/150 Test  #59: bgetam--presolve=off ...................   Passed    0.06 sec
        Start  60: bgetam--presolve=on
 60/150 Test  #60: bgetam--presolve=on ....................   Passed    0.08 sec
        Start  61: bgetam--random_seed=1
 61/150 Test  #61: bgetam--random_seed=1 ..................   Passed    0.08 sec
        Start  62: bgetam--random_seed=2
 62/150 Test  #62: bgetam--random_seed=2 ..................   Passed    0.08 sec
        Start  63: bgetam--random_seed=3
 63/150 Test  #63: bgetam--random_seed=3 ..................   Passed    0.08 sec
        Start  64: box1--presolve=off
 64/150 Test  #64: box1--presolve=off .....................   Passed    0.04 sec
        Start  65: box1--presolve=on
 65/150 Test  #65: box1--presolve=on ......................   Passed    0.05 sec
        Start  66: box1--random_seed=1
 66/150 Test  #66: box1--random_seed=1 ....................   Passed    0.05 sec
        Start  67: box1--random_seed=2
 67/150 Test  #67: box1--random_seed=2 ....................   Passed    0.05 sec
        Start  68: box1--random_seed=3
 68/150 Test  #68: box1--random_seed=3 ....................   Passed    0.05 sec
        Start  69: ex72a--presolve=off
 69/150 Test  #69: ex72a--presolve=off ....................   Passed    0.05 sec
        Start  70: ex72a--presolve=on
 70/150 Test  #70: ex72a--presolve=on .....................   Passed    0.04 sec
        Start  71: ex72a--random_seed=1
 71/150 Test  #71: ex72a--random_seed=1 ...................   Passed    0.04 sec
        Start  72: ex72a--random_seed=2
 72/150 Test  #72: ex72a--random_seed=2 ...................   Passed    0.04 sec
        Start  73: ex72a--random_seed=3
 73/150 Test  #73: ex72a--random_seed=3 ...................   Passed    0.04 sec
        Start  74: forest6--presolve=off
 74/150 Test  #74: forest6--presolve=off ..................   Passed    0.04 sec
        Start  75: forest6--presolve=on
 75/150 Test  #75: forest6--presolve=on ...................   Passed    0.05 sec
        Start  76: forest6--random_seed=1
 76/150 Test  #76: forest6--random_seed=1 .................   Passed    0.05 sec
        Start  77: forest6--random_seed=2
 77/150 Test  #77: forest6--random_seed=2 .................   Passed    0.04 sec
        Start  78: forest6--random_seed=3
 78/150 Test  #78: forest6--random_seed=3 .................   Passed    0.05 sec
        Start  79: galenet--presolve=off
 79/150 Test  #79: galenet--presolve=off ..................   Passed    0.03 sec
        Start  80: galenet--presolve=on
 80/150 Test  #80: galenet--presolve=on ...................   Passed    0.03 sec
        Start  81: galenet--random_seed=1
 81/150 Test  #81: galenet--random_seed=1 .................   Passed    0.03 sec
        Start  82: galenet--random_seed=2
 82/150 Test  #82: galenet--random_seed=2 .................   Passed    0.03 sec
        Start  83: galenet--random_seed=3
 83/150 Test  #83: galenet--random_seed=3 .................   Passed    0.03 sec
        Start  84: gams10am--presolve=off
 84/150 Test  #84: gams10am--presolve=off .................   Passed    0.04 sec
        Start  85: gams10am--presolve=on
 85/150 Test  #85: gams10am--presolve=on ..................   Passed    0.03 sec
        Start  86: gams10am--random_seed=1
 86/150 Test  #86: gams10am--random_seed=1 ................   Passed    0.03 sec
        Start  87: gams10am--random_seed=2
 87/150 Test  #87: gams10am--random_seed=2 ................   Passed    0.03 sec
        Start  88: gams10am--random_seed=3
 88/150 Test  #88: gams10am--random_seed=3 ................   Passed    0.03 sec
        Start  89: refinery--presolve=off
 89/150 Test  #89: refinery--presolve=off .................   Passed    0.08 sec
        Start  90: refinery--presolve=on
 90/150 Test  #90: refinery--presolve=on ..................   Passed    0.08 sec
        Start  91: refinery--random_seed=1
 91/150 Test  #91: refinery--random_seed=1 ................   Passed    0.08 sec
        Start  92: refinery--random_seed=2
 92/150 Test  #92: refinery--random_seed=2 ................   Passed    0.08 sec
        Start  93: refinery--random_seed=3
 93/150 Test  #93: refinery--random_seed=3 ................   Passed    0.08 sec
        Start  94: woodinfe--presolve=off
 94/150 Test  #94: woodinfe--presolve=off .................   Passed    0.03 sec
        Start  95: woodinfe--presolve=on
 95/150 Test  #95: woodinfe--presolve=on ..................   Passed    0.03 sec
        Start  96: woodinfe--random_seed=1
 96/150 Test  #96: woodinfe--random_seed=1 ................   Passed    0.03 sec
        Start  97: woodinfe--random_seed=2
 97/150 Test  #97: woodinfe--random_seed=2 ................   Passed    0.03 sec
        Start  98: woodinfe--random_seed=3
 98/150 Test  #98: woodinfe--random_seed=3 ................   Passed    0.03 sec
        Start  99: small_mip--presolve=off
 99/150 Test  #99: small_mip--presolve=off ................   Passed    0.04 sec
        Start 100: small_mip--presolve=on
100/150 Test #100: small_mip--presolve=on .................   Passed    0.03 sec
        Start 101: small_mip--random_seed=1
101/150 Test #101: small_mip--random_seed=1 ...............   Passed    0.03 sec
        Start 102: small_mip--random_seed=2
102/150 Test #102: small_mip--random_seed=2 ...............   Passed    0.03 sec
        Start 103: small_mip--random_seed=3
103/150 Test #103: small_mip--random_seed=3 ...............   Passed    0.03 sec
        Start 104: flugpl--presolve=off
104/150 Test #104: flugpl--presolve=off ...................   Passed    0.69 sec
        Start 105: flugpl--presolve=on
105/150 Test #105: flugpl--presolve=on ....................   Passed    1.03 sec
        Start 106: flugpl--random_seed=1
106/150 Test #106: flugpl--random_seed=1 ..................   Passed    0.87 sec
        Start 107: flugpl--random_seed=2
107/150 Test #107: flugpl--random_seed=2 ..................   Passed    1.01 sec
        Start 108: flugpl--random_seed=3
108/150 Test #108: flugpl--random_seed=3 ..................   Passed    1.10 sec
        Start 109: lseu--presolve=off
109/150 Test #109: lseu--presolve=off .....................   Passed    1.29 sec
        Start 110: lseu--presolve=on
110/150 Test #110: lseu--presolve=on ......................   Passed    3.29 sec
        Start 111: lseu--random_seed=1
111/150 Test #111: lseu--random_seed=1 ....................   Passed    4.88 sec
        Start 112: lseu--random_seed=2
112/150 Test #112: lseu--random_seed=2 ....................   Passed    3.79 sec
        Start 113: lseu--random_seed=3
113/150 Test #113: lseu--random_seed=3 ....................   Passed    2.80 sec
        Start 114: egout--presolve=off
114/150 Test #114: egout--presolve=off ....................   Passed    0.15 sec
        Start 115: egout--presolve=on
115/150 Test #115: egout--presolve=on .....................   Passed    0.12 sec
        Start 116: egout--random_seed=1
116/150 Test #116: egout--random_seed=1 ...................   Passed    0.12 sec
        Start 117: egout--random_seed=2
117/150 Test #117: egout--random_seed=2 ...................   Passed    0.12 sec
        Start 118: egout--random_seed=3
118/150 Test #118: egout--random_seed=3 ...................   Passed    0.12 sec
        Start 119: gt2--presolve=off
119/150 Test #119: gt2--presolve=off ......................   Passed    0.44 sec
        Start 120: gt2--presolve=on
120/150 Test #120: gt2--presolve=on .......................   Passed    0.57 sec
        Start 121: gt2--random_seed=1
121/150 Test #121: gt2--random_seed=1 .....................   Passed    0.78 sec
        Start 122: gt2--random_seed=2
122/150 Test #122: gt2--random_seed=2 .....................   Passed    0.37 sec
        Start 123: gt2--random_seed=3
123/150 Test #123: gt2--random_seed=3 .....................   Passed    0.39 sec
        Start 124: rgn--presolve=off
124/150 Test #124: rgn--presolve=off ......................   Passed    2.09 sec
        Start 125: rgn--presolve=on
125/150 Test #125: rgn--presolve=on .......................   Passed    2.05 sec
        Start 126: rgn--random_seed=1
126/150 Test #126: rgn--random_seed=1 .....................   Passed    1.68 sec
        Start 127: rgn--random_seed=2
127/150 Test #127: rgn--random_seed=2 .....................   Passed    1.94 sec
        Start 128: rgn--random_seed=3
128/150 Test #128: rgn--random_seed=3 .....................   Passed    2.16 sec
        Start 129: bell5--presolve=off
129/150 Test #129: bell5--presolve=off ....................   Passed    9.61 sec
        Start 130: bell5--presolve=on
130/150 Test #130: bell5--presolve=on .....................   Passed    8.96 sec
        Start 131: bell5--random_seed=1
131/150 Test #131: bell5--random_seed=1 ...................   Passed    6.33 sec
        Start 132: bell5--random_seed=2
132/150 Test #132: bell5--random_seed=2 ...................   Passed    7.59 sec
        Start 133: bell5--random_seed=3
133/150 Test #133: bell5--random_seed=3 ...................   Passed    6.46 sec
        Start 134: sp150x300d--presolve=off
134/150 Test #134: sp150x300d--presolve=off ...............   Passed    2.57 sec
        Start 135: sp150x300d--presolve=on
135/150 Test #135: sp150x300d--presolve=on ................   Passed    0.40 sec
        Start 136: sp150x300d--random_seed=1
136/150 Test #136: sp150x300d--random_seed=1 ..............   Passed    0.41 sec
        Start 137: sp150x300d--random_seed=2
137/150 Test #137: sp150x300d--random_seed=2 ..............   Passed    0.37 sec
        Start 138: sp150x300d--random_seed=3
138/150 Test #138: sp150x300d--random_seed=3 ..............   Passed    0.38 sec
        Start 139: p0548--presolve=off
139/150 Test #139: p0548--presolve=off ....................   Passed    0.77 sec
        Start 140: p0548--presolve=on
140/150 Test #140: p0548--presolve=on .....................   Passed    0.66 sec
        Start 141: p0548--random_seed=1
141/150 Test #141: p0548--random_seed=1 ...................   Passed    0.71 sec
        Start 142: p0548--random_seed=2
142/150 Test #142: p0548--random_seed=2 ...................   Passed    0.65 sec
        Start 143: p0548--random_seed=3
143/150 Test #143: p0548--random_seed=3 ...................   Passed    0.70 sec
        Start 144: dcmulti--presolve=off
144/150 Test #144: dcmulti--presolve=off ..................   Passed   15.91 sec
        Start 145: dcmulti--presolve=on
145/150 Test #145: dcmulti--presolve=on ...................   Passed    8.47 sec
        Start 146: dcmulti--random_seed=1
146/150 Test #146: dcmulti--random_seed=1 .................   Passed   11.02 sec
        Start 147: dcmulti--random_seed=2
147/150 Test #147: dcmulti--random_seed=2 .................   Passed   10.53 sec
        Start 148: dcmulti--random_seed=3
148/150 Test #148: dcmulti--random_seed=3 .................   Passed    6.31 sec
        Start 149: cxx_examples_call_highs_from_cpp
149/150 Test #149: cxx_examples_call_highs_from_cpp .......   Passed    0.04 sec
        Start 150: c_examples_call_highs_from_c_minimal
150/150 Test #150: c_examples_call_highs_from_c_minimal ...   Passed    0.07 sec

96% tests passed, 6 tests failed out of 150

Total Test time (real) = 201.84 sec

The following tests FAILED:
	 3 - unit_tests_all (Failed)
	 4 - 25fv47--presolve=off (Failed)
	 9 - 80bau3b--presolve=off (Failed)
	24 - etamacro--presolve=off (Failed)
	29 - greenbea--presolve=off (Failed)
	39 - stair--presolve=off (Failed)
Errors while running CTest

Let me see if I can find what went wrong.

[orlitzky]

One looks like,

/home/mjo/src/HiGHS.git/check/TestLpSolvers.cpp:286: FAILED:
  REQUIRE( info.simplex_iteration_count == 472 )
with expansion:
  437 (0x1b5) == 472 (0x1d8)

But all the others are variations on this regex-not-found:

Running HiGHS 1.8.0 (git hash: fcfb534): Copyright (c) 2024 HiGHS under MIT licence \
terms
LP   25fv47 has 821 rows; 1571 cols; 10400 nonzeros
Coefficient ranges:
  Matrix [2e-04, 2e+02]
  Cost   [1e-03, 1e+02]
  Bound  [0e+00, 0e+00]
  RHS    [2e-01, 2e+03]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -8.6641744311e+01 Ph1: 79(245.084); Du: 41(86.6417) 0s
       3103     5.5018458883e+03 Pr: 0(0); Du: 0(5.15143e-14) 1s
Model   status      : Optimal
Simplex   iterations: 3103
Objective value     :  5.5018458883e+03
HiGHS run time      :          0.82
<end of output>
Test time =   0.93 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 3149
Objective value     :  5.5018458883
]
"25fv47--presolve=off" end time: Oct 25 07:27 EDT
"25fv47--presolve=off" time elapsed: 00:00:00
----------------------------------------------------------

[jajhall]

These iteration count tests are indicators of a logical difference in the way that the simplex solver runs on a particular architecture: no error has occurred.

They can be caused by compiler optimizations

[galabovaa]

It is worth considering modifying our tests so the iteration counts are only checked on particular architectures that we have tested on. Since it is expected for them to differ.

I guess the objective values differ with a value below 1e-08.

For macOS arm I have added different objective values and iterations to ctest for the instances that differ, and the ones above seem to be a subset. In way what you show is expected.

Is it possible for you to run ctest --verbose and send me the (possibly rather large) output, so I could use the values to do the same?

[orlitzky]

Is it possible for you to run ctest --verbose and send me the (possibly rather large) output, so I could use the values to do the same?

No problem, here you go:

ctest-verbose.log.zip

[galabovaa]

Thank you! I will add the iteration counts for RICS-V in cmake :)

[galabovaa]

Hi @orlitzky

I have added the iteration count modifications to branch risc-v:

https://github.com/ERGO-Code/HiGHS/tree/risc-v

Could you please check whether there are any tests that are still failing?

Once those are cleared I can merge it in latest.

[orlitzky]

I admit I was trying to trick it, but I did succeed by switching to -O1 with gcc. Summary:

The following tests FAILED:
	 4 - 25fv47--presolve=off (Failed)
	 9 - 80bau3b--presolve=off (Failed)
	14 - etamacro--presolve=off (Failed)
	19 - greenbea--presolve=off (Failed)
	24 - stair--presolve=off (Failed)

Details:

Running HiGHS 1.8.0 (git hash: 7af271225): Copyright (c) 2024 HiGHS under MIT licence terms
LP   25fv47 has 821 rows; 1571 cols; 10400 nonzeros
Coefficient ranges:
  Matrix [2e-04, 2e+02]
  Cost   [1e-03, 1e+02]
  Bound  [0e+00, 0e+00]
  RHS    [2e-01, 2e+03]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -8.6641744311e+01 Ph1: 79(245.084); Du: 41(86.6417) 0s
       3149     5.5018458883e+03 Pr: 0(0); Du: 0(3.10862e-14) 1s
Model name          : 25fv47
Model status        : Optimal
Simplex   iterations: 3149
Objective value     :  5.5018458883e+03
Highs::reportSolvedLpQpStats Objective for 25fv47: primal =  5.5018458883e+03; dual =  5.5018458883e+03; rel gap =  1.8183791263e-15
HiGHS run time      :          0.91
<end of output>
Test time =   1.03 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 3103
Objective value     :  5.5018458883
]
"25fv47--presolve=off" end time: Oct 30 23:41 EDT
"25fv47--presolve=off" time elapsed: 00:00:01

Running HiGHS 1.8.0 (git hash: 7af271225): Copyright (c) 2024 HiGHS under MIT licence terms
LP   80bau3b has 2262 rows; 9799 cols; 21002 nonzeros
Coefficient ranges:
  Matrix [2e-04, 1e+02]
  Cost   [1e-03, 3e+03]
  Bound  [7e-05, 1e+06]
  RHS    [1e-03, 5e+03]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -3.4167145836e+02 Ph1: 101(295.75); Du: 208(341.671) 0s
       3686     9.8722419241e+05 Pr: 0(0); Du: 0(1.58429e-13) 1s
Model name          : 80bau3b
Model status        : Optimal
Simplex   iterations: 3686
Objective value     :  9.8722419241e+05
Highs::reportSolvedLpQpStats Objective for 80bau3b: primal =  9.8722419241e+05; dual =  9.8722419241e+05; rel gap =  5.8960934468e-16
HiGHS run time      :          0.65
<end of output>
Test time =   0.94 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 3705
Objective value     :  9.8722419241
]
"80bau3b--presolve=off" end time: Oct 30 23:41 EDT
"80bau3b--presolve=off" time elapsed: 00:00:00

Running HiGHS 1.8.0 (git hash: 7af271225): Copyright (c) 2024 HiGHS under MIT licence terms
LP   etamacro has 400 rows; 688 cols; 2409 nonzeros
Coefficient ranges:
  Matrix [2e-02, 2e+03]
  Cost   [8e-03, 8e+02]
  Bound  [3e-02, 1e+02]
  RHS    [1e+00, 1e+04]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -2.9562269393e+01 Ph1: 46(77.0946); Du: 45(29.5623) 0s
        530    -7.5571523130e+02 Pr: 0(0); Du: 0(1.87426e-07) 0s
        530    -7.5571523130e+02 Pr: 0(0); Du: 0(1.87426e-07) 0s
Using EKK primal simplex solver
  Iteration        Objective     Infeasibilities num(sum)
        530    -7.5571523130e+02 Pr: 0(0); Du: 1(1.46689e-06) 0s
        532    -7.5571523330e+02 Pr: 0(0); Du: 0(1.05135e-07) 0s
Model name          : etamacro
Model status        : Optimal
Simplex   iterations: 532
Objective value     : -7.5571523330e+02
Highs::reportSolvedLpQpStats Objective for etamacro: primal = -7.5571523330e+02; dual = -7.5571523330e+02; rel gap =  1.5043608057e-16
HiGHS run time      :          0.06
<end of output>
Test time =   0.12 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 531
Objective value     : -7.5571523330
]
"etamacro--presolve=off" end time: Oct 30 23:41 EDT
"etamacro--presolve=off" time elapsed: 00:00:00

Running HiGHS 1.8.0 (git hash: 7af271225): Copyright (c) 2024 HiGHS under MIT licence terms
LP   greenbea has 2392 rows; 5405 cols; 30877 nonzeros
Coefficient ranges:
  Matrix [6e-05, 1e+02]
  Cost   [6e-02, 1e+02]
  Bound  [1e+00, 1e+04]
  RHS    [0e+00, 0e+00]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -1.7539523835e+01 Ph1: 6(3.75); Du: 6(17.5395) 0s
       5109    -7.2555248130e+07 Pr: 0(0); Du: 0(1.01554e-11) 3s
       5109    -7.2555248130e+07 Pr: 0(0); Du: 0(1.01554e-11) 3s
Model name          : greenbea
Model status        : Optimal
Simplex   iterations: 5109
Objective value     : -7.2555248130e+07
Highs::reportSolvedLpQpStats Objective for greenbea: primal = -7.2555248130e+07; dual = -7.2555248130e+07; rel gap =  1.4376372633e-15
HiGHS run time      :          3.36
<end of output>
Test time =   3.62 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 5156
Objective value     : -7.2555248130
]
"greenbea--presolve=off" end time: Oct 30 23:41 EDT
"greenbea--presolve=off" time elapsed: 00:00:03

Running HiGHS 1.8.0 (git hash: 7af271225): Copyright (c) 2024 HiGHS under MIT licence terms
LP   stair has 356 rows; 467 cols; 3856 nonzeros
Coefficient ranges:
  Matrix [1e-05, 1e+01]
  Cost   [1e+00, 1e+00]
  Bound  [1e-01, 3e+02]
  RHS    [3e-02, 9e+01]
Solving LP without presolve, or with basis, or unconstrained
Using EKK dual simplex solver - serial
  Iteration        Objective     Infeasibilities num(sum)
          0    -5.1199799154e+02 Ph1: 36(27170.7); Du: 1(511.998) 0s
        529    -2.5126695119e+02 Pr: 0(0) 0s
Model name          : stair
Model status        : Optimal
Simplex   iterations: 529
Objective value     : -2.5126695119e+02
Highs::reportSolvedLpQpStats Objective for stair: primal = -2.5126695119e+02; dual = -2.5126695119e+02; rel gap =  9.0490880063e-16
HiGHS run time      :          0.09
<end of output>
Test time =   0.15 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[Simplex   iterations: 531
Objective value     : -2.5126695119
]
"stair--presolve=off" end time: Oct 30 23:41 EDT
"stair--presolve=off" time elapsed: 00:00:00

[galabovaa]

This trick is expected to work: changing levels of compiler optimizations is expected to change iteration counts. We've had a discusstion about it recently with some new compiler friends.

We only really test for the default -O2. So, apart from the trick, did ctest pass with the default setting? :)

[galabovaa]

I suppose it may be worth to modify CMake, so the iteration count tests are only executed if the level of -O is not modified by the user. I would be happy to do this on another branch. This bit I could test locally too, since it would also fail on macos ARM / windows or linux with amd64 too.

[orlitzky]

Yes, it worked with the same compiler/flags as in my original report.

Out of the box, CMake will actually use -O3 unless you override it. For example,

cd /home/mjo/src/HiGHS.git/build/src && /usr/lib/llvm/19/bin/clang++ -DNDEBUG -Dhighs_EXPORTS -I/home/mjo/src/HiGHS.git/src -I/home/mjo/src/HiGHS.git/build -I/home/mjo/src/HiGHS.git/extern -I/home/mjo/src/HiGHS.git/extern/filereader -I/home/mjo/src/HiGHS.git/extern/pdqsort -I/home/mjo/src/HiGHS.git/extern/zstr -I/home/mjo/src/HiGHS.git/src/interfaces -I/home/mjo/src/HiGHS.git/src/io -I/home/mjo/src/HiGHS.git/src/ipm -I/home/mjo/src/HiGHS.git/src/ipm/ipx -I/home/mjo/src/HiGHS.git/src/ipm/basiclu -I/home/mjo/src/HiGHS.git/src/lp_data -I/home/mjo/src/HiGHS.git/src/mip -I/home/mjo/src/HiGHS.git/src/model -I/home/mjo/src/HiGHS.git/src/parallel -I/home/mjo/src/HiGHS.git/src/pdlp -I/home/mjo/src/HiGHS.git/src/pdlp/cupdlp -I/home/mjo/src/HiGHS.git/src/presolve -I/home/mjo/src/HiGHS.git/src/qpsolver -I/home/mjo/src/HiGHS.git/src/simplex -I/home/mjo/src/HiGHS.git/src/test -I/home/mjo/src/HiGHS.git/src/util -O2 -pipe -mabi=lp64d -march=rv64gc -O3 -DNDEBUG -std=c++11 -flto=thin -fPIC -Wno-unused-variable -Wno-unused-const-variable -MD -MT src/CMakeFiles/highs.dir//extern/filereaderlp/reader.cpp.o -MF CMakeFiles/highs.dir//extern/filereaderlp/reader.cpp.o.d -o CMakeFiles/highs.dir/__/extern/filereaderlp/reader.cpp.o -c /home/mjo/src/HiGHS.git/extern/filereaderlp/reader.cpp

My CXXFLAGS are -O2 -pipe -mabi=lp64d -march=rv64gc but the rest (including -O3) were added by CMake, and the -O3 takes precedence because it comes later on the CLI.

IMO you're likely to run into the same sort of problem with changing CC/CXX as well.