Better support for symbolic ranges #21932

oscargus · 2021-08-23T11:05:42Z

References to other Issues or PRs

Closes #18400

Brief description of what is fixed or changed

I started playing around with symbolic ranges and this seems to pass all the tests I ran at home.

If this seems like a way forward, I will add tests for #18400. (And try to fix any failing test...)

Other comments

Release Notes

sets
- Better support for symbolic Range.

sympy-bot · 2021-08-23T11:05:50Z

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sets
- Better support for symbolic Range. (#21932 by @oscargus and @smichr)

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Closes #18400

#### Brief description of what is fixed or changed
I started playing around with symbolic ranges and this seems to pass all the tests I ran at home.

If this seems like a way forward, I will add tests for #18400. (And try to fix any failing test...)

#### Other comments


#### Release Notes

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  * Added a new solver for logarithmic equations.

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  * Fixed a bug with log of integers.

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* sets
   * Better support for symbolic `Range`.
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Update

The release notes on the wiki have been updated.

oscargus · 2021-08-23T11:21:13Z

I understand this is by convention, but not really obvious anyway (and a bit annoying here):

In [29]: oo.is_positive
Out[29]: False

In [30]: oo > 0
Out[30]: True

oscarbenjamin · 2021-08-23T11:26:28Z

In [1]: oo.is_extended_positive
Out[1]: True

New docs explaining this:
https://docs.sympy.org/dev/guides/assumptions.html#predicates

github-actions · 2021-08-23T12:29:20Z

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)

Significantly changed benchmark results (master vs previous release)

       before           after         ratio
     [ed9a550f]       [b4c1da60]
     <sympy-1.8^0>                 
-         913±4ms        125±0.8ms     0.14  dsolve.TimeDsolve01.time_dsolve
-      7.71±0.03s       4.01±0.01s     0.52  integrate.TimeIntegrationRisch02.time_doit(100)
-      7.75±0.01s       4.02±0.01s     0.52  integrate.TimeIntegrationRisch02.time_doit_risch(100)
-      65.9±0.9μs       25.4±0.3μs     0.39  matrices.TimeDiagonalEigenvals.time_eigenvals
-        78.1±2μs       51.0±0.8μs     0.65  matrices.TimeMatrixGetItem.time_ImmutableDenseMatrix_getitem
-      80.5±0.7μs       51.4±0.8μs     0.64  matrices.TimeMatrixGetItem.time_ImmutableSparseMatrix_getitem
-      79.1±0.5μs       51.0±0.5μs     0.64  matrices.TimeMatrixGetItem.time_MutableSparseMatrix_getitem
+        76.8±1μs          123±1μs     1.60  solve.TimeMatrixArithmetic.time_dense_add(10, 5)
+     10.4±0.07μs       17.0±0.2μs     1.63  solve.TimeMatrixArithmetic.time_dense_add(3, 0)
+      12.3±0.2μs       27.3±0.5μs     2.22  solve.TimeMatrixArithmetic.time_dense_add(3, 5)
+      18.1±0.3μs         34.8±1μs     1.92  solve.TimeMatrixArithmetic.time_dense_add(4, 5)
+      33.0±0.3μs       57.6±0.8μs     1.75  solve.TimeMatrixArithmetic.time_dense_add(6, 5)
-     1.10±0.01ms          226±3μs     0.21  solve.TimeMatrixArithmetic.time_dense_multiply(10, 0)
-      40.9±0.5μs       22.3±0.4μs     0.54  solve.TimeMatrixArithmetic.time_dense_multiply(3, 0)
+      64.7±0.3μs          117±2μs     1.80  solve.TimeMatrixArithmetic.time_dense_multiply(3, 5)
-        88.1±1μs       29.5±0.3μs     0.33  solve.TimeMatrixArithmetic.time_dense_multiply(4, 0)
-         263±2μs       63.9±0.3μs     0.24  solve.TimeMatrixArithmetic.time_dense_multiply(6, 0)
-      82.5±0.3μs       37.4±0.3μs     0.45  solve.TimeMatrixOperations.time_det(3, 0)
-       154±0.4μs       89.5±0.5μs     0.58  solve.TimeMatrixOperations.time_det(3, 2)
-         143±3μs       80.2±0.5μs     0.56  solve.TimeMatrixOperations.time_det(3, 5)
-      82.8±0.7μs       37.8±0.8μs     0.46  solve.TimeMatrixOperations.time_det_bareiss(3, 0)
-         154±1μs         91.5±1μs     0.59  solve.TimeMatrixOperations.time_det_bareiss(3, 2)
-         144±2μs       82.5±0.7μs     0.57  solve.TimeMatrixOperations.time_det_bareiss(3, 5)
-        82.6±1μs       37.5±0.3μs     0.45  solve.TimeMatrixOperations.time_det_berkowitz(3, 0)
-         153±2μs       89.6±0.9μs     0.58  solve.TimeMatrixOperations.time_det_berkowitz(3, 2)
-         145±1μs       80.3±0.7μs     0.55  solve.TimeMatrixOperations.time_det_berkowitz(3, 5)
+         684±5μs      1.09±0.01ms     1.59  solve.TimeMatrixOperations.time_det_berkowitz(4, 0)
+        856±10μs      1.55±0.02ms     1.81  solve.TimeMatrixOperations.time_det_berkowitz(4, 2)
+        883±10μs      1.65±0.02ms     1.86  solve.TimeMatrixOperations.time_det_berkowitz(4, 5)
+         250±8μs          412±3μs     1.64  solve.TimeMatrixOperations.time_rank(3, 0)
+         390±7μs          619±9μs     1.59  solve.TimeMatrixOperations.time_rank(4, 0)
+         113±2μs          172±2μs     1.52  solve.TimeMatrixOperations.time_rref(3, 0)
-      4.51±0.1ms      2.76±0.08ms     0.61  solve.TimeRationalSystem.time_linsolve(10)
+         908±8μs      1.36±0.02ms     1.50  solve.TimeSparseSystem.time_linear_eq_to_matrix(10)

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

oscargus · 2021-08-23T12:35:03Z

Thanks! Forgot about those extended ones...

oscargus · 2021-08-24T13:07:18Z

One may want to consider a SymbolicRangeError which inherits from ValueError (or maybe TypeError sometimes that is thrown as well).

smichr · 2021-08-24T14:37:01Z

sympy/sets/tests/test_fancysets.py

+    assert Range(n)[0] == 0
+    assert Range(n, n+1)[0] == n
+    assert Range(n).size == n
+    assert Range(n, n+1).size == 1


nice progression of tests!

sympy/sets/fancysets.py

smichr · 2021-08-24T14:47:14Z

lgtm

oscargus added the sets label Aug 23, 2021

Better support for symbolic ranges

0d4208d

oscargus force-pushed the symbolicranges branch from b763e68 to 0d4208d Compare August 23, 2021 11:15

oscargus mentioned this pull request Aug 24, 2021

imageset over Range does not work #18400

Closed

oscargus force-pushed the symbolicranges branch from 8fb28a7 to 102dab5 Compare August 24, 2021 13:02

Fixed some minor issues and added tests

b54c0ad

oscargus force-pushed the symbolicranges branch from 102dab5 to b54c0ad Compare August 24, 2021 13:03

smichr reviewed Aug 24, 2021

View reviewed changes

sympy/sets/fancysets.py Outdated Show resolved Hide resolved

typo

f714f78

smichr merged commit 6fdba11 into sympy:master Aug 24, 2021

oscargus mentioned this pull request Aug 25, 2021

sets - fixes imageset does not work over range #21794

Closed

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oscargus commented Aug 23, 2021

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Release Notes

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