Reorder hints in dsolve

[Mohitbalwani26]

References to other Issues or PRs

SEE #18348

Brief description of what is fixed or changed

Ordering of hints is changed in dsolve.

Other comments

Release Notes

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SEE #18348 

#### Brief description of what is fixed or changed
Ordering of hints is changed in dsolve.

#### Other comments


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[github-actions]

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

       before           after         ratio
     [5a5904ed]       [4538c33e]
-         1.26±0s        129±0.2ms     0.10  dsolve.TimeDsolve01.time_dsolve

Significantly changed benchmark results (master vs previous release)

       before           after         ratio
     [ed9a550f]       [5a5904ed]
     <sympy-1.8^0>                 
-      8.79±0.01s       4.25±0.01s     0.48  integrate.TimeIntegrationRisch02.time_doit(100)
-         8.84±0s          4.23±0s     0.48  integrate.TimeIntegrationRisch02.time_doit_risch(100)
-     14.3±0.01ms      9.49±0.02ms     0.66  logic.LogicSuite.time_load_file
-      74.8±0.2μs      30.2±0.06μs     0.40  matrices.TimeDiagonalEigenvals.time_eigenvals
-      91.7±0.4μs       59.8±0.4μs     0.65  matrices.TimeMatrixGetItem.time_ImmutableDenseMatrix_getitem
-      91.4±0.4μs       59.9±0.3μs     0.66  matrices.TimeMatrixGetItem.time_ImmutableSparseMatrix_getitem
-      89.8±0.3μs       58.8±0.2μs     0.66  matrices.TimeMatrixGetItem.time_MutableSparseMatrix_getitem
-     84.6±0.09μs       52.1±0.1μs     0.62  solve.TimeMatrixArithmetic.time_dense_add(10, 0)
+     11.6±0.01μs      18.9±0.04μs     1.63  solve.TimeMatrixArithmetic.time_dense_add(3, 0)
+     14.0±0.08μs       30.6±0.1μs     2.18  solve.TimeMatrixArithmetic.time_dense_add(3, 5)
+     20.7±0.06μs      39.3±0.07μs     1.90  solve.TimeMatrixArithmetic.time_dense_add(4, 5)
+      37.4±0.1μs       63.3±0.1μs     1.69  solve.TimeMatrixArithmetic.time_dense_add(6, 5)
-        1.24±0ms        220±0.6μs     0.18  solve.TimeMatrixArithmetic.time_dense_multiply(10, 0)
-      48.0±0.1μs      25.1±0.02μs     0.52  solve.TimeMatrixArithmetic.time_dense_multiply(3, 0)
+      75.3±0.2μs        133±0.3μs     1.76  solve.TimeMatrixArithmetic.time_dense_multiply(3, 5)
-       101±0.2μs      31.8±0.04μs     0.31  solve.TimeMatrixArithmetic.time_dense_multiply(4, 0)
-         298±1μs      64.3±0.06μs     0.22  solve.TimeMatrixArithmetic.time_dense_multiply(6, 0)
-      91.4±0.3μs       43.1±0.2μs     0.47  solve.TimeMatrixOperations.time_det(3, 0)
-       166±0.2μs       98.9±0.2μs     0.59  solve.TimeMatrixOperations.time_det(3, 2)
-       157±0.3μs      90.7±0.06μs     0.58  solve.TimeMatrixOperations.time_det(3, 5)
-      91.8±0.3μs       43.2±0.2μs     0.47  solve.TimeMatrixOperations.time_det_bareiss(3, 0)
-       167±0.4μs       99.2±0.3μs     0.59  solve.TimeMatrixOperations.time_det_bareiss(3, 2)
-       158±0.1μs       90.6±0.1μs     0.57  solve.TimeMatrixOperations.time_det_bareiss(3, 5)
-      92.1±0.3μs       43.3±0.2μs     0.47  solve.TimeMatrixOperations.time_det_berkowitz(3, 0)
-       167±0.3μs       98.9±0.3μs     0.59  solve.TimeMatrixOperations.time_det_berkowitz(3, 2)
-       158±0.4μs      90.7±0.05μs     0.58  solve.TimeMatrixOperations.time_det_berkowitz(3, 5)
+         723±2μs         1.10±0ms     1.52  solve.TimeMatrixOperations.time_det_berkowitz(4, 0)
+         867±1μs         1.60±0ms     1.84  solve.TimeMatrixOperations.time_det_berkowitz(4, 2)
+         902±1μs         1.70±0ms     1.89  solve.TimeMatrixOperations.time_det_berkowitz(4, 5)
+       266±0.8μs          426±2μs     1.60  solve.TimeMatrixOperations.time_rank(3, 0)
+         419±3μs        646±0.7μs     1.54  solve.TimeMatrixOperations.time_rank(4, 0)
+       122±0.2μs        183±0.3μs     1.50  solve.TimeMatrixOperations.time_rref(3, 0)
-        5.10±0ms         2.82±0ms     0.55  solve.TimeRationalSystem.time_linsolve(10)
-        1.03±0ms          652±1μs     0.63  solve.TimeRationalSystem.time_linsolve(5)
+     6.25±0.02ms      9.40±0.02ms     1.50  solve.TimeSparseSystem.time_linear_eq_to_matrix(30)
-        1.20±0ms          796±1μs     0.66  solve.TimeSparseSystem.time_linsolve_eqs(10)
-        2.26±0ms         1.44±0ms     0.64  solve.TimeSparseSystem.time_linsolve_eqs(20)
-        3.36±0ms         2.10±0ms     0.63  solve.TimeSparseSystem.time_linsolve_eqs(30)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

[oscarbenjamin]

Ideally odesimp or constantsimp would make the output the same here regardless of which hint is used.

[oscarbenjamin]

I see that the dsolve benchmark has improved but there are only limited examples there.

Can you give timings for particular ODEs?

Does the time needed for the test suite change because of this?

With these improvements what takes the most time now if you profile dsolve?

[oscarbenjamin]

Looks good!