New Y-Boundaries for unified sheath code by dschwoerer · Pull Request #3308 · boutproject/BOUT-dev

dschwoerer · 2026-03-05T08:10:18Z

This allows to implement unified BCs for yup/ydown as well as FCI / FA.
Taking into acount things like whether the boundary is next to the domain, or between the parallel slices.

github-actions

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clang-tidy made some suggestions

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Makes it easier to reuse for other code

Mimicks the parallel case, to write FCI independent code

The boundary region does not match what is done for the parallel case, thus porting it to a iterator does not work.

hasBndryUpperY / hasBndryLowerY does not work for FCI and thus the request does not make sense / can be configured to throw. Thus it should not be checked if it is not needed.

BoundaryRegionIter has been delted

This allows to extend the boundary code to place the boundary further away from the boundary.

This is more general and takes the offset() into account, and thus works for cases where the boundary is between the first and second guard cell

Previously only the first boundary point was set

Taken from hermes-3, adopted for higher order

This allows to write code for FCI and non-FCI using templates.

Directly iterate over the points

github-actions

clang-tidy made some suggestions

There were too many comments to post at once. Showing the first 25 out of 79. Check the log or trigger a new build to see more.

github-actions · 2026-05-26T07:13:29Z

+#include "bout/assert.hxx"
+#include "bout/bout_types.hxx"
+#include "bout/build_defines.hxx"
+#include "bout/field2d.hxx"


warning: included header build_defines.hxx is not used directly [misc-include-cleaner]

Suggested change

#include "bout/field2d.hxx"

#include "bout/field2d.hxx"

github-actions · 2026-05-26T07:13:29Z

+  int y() const { return _y; }
+  int z() const { return _z; }
+
+protected:


warning: redundant access specifier has the same accessibility as the previous access specifier [readability-redundant-access-specifiers]

Suggested change

protected:

Additional context

include/bout/boundary_iterator.hxx:157: previously declared here

protected: ^

github-actions · 2026-05-26T07:13:29Z

+#include <functional>
+#include <string>
+#include <utility>
+


warning: included header utility is not used directly [misc-include-cleaner]

Suggested change

github-actions · 2026-05-26T07:13:30Z

+#include <utility>
+
+#include <bout/bout_enum_class.hxx>
+#include <bout/field2d.hxx>


warning: included header bout_enum_class.hxx is not used directly [misc-include-cleaner]

Suggested change

#include <bout/field2d.hxx>

#include <bout/field2d.hxx>

github-actions · 2026-05-26T07:13:30Z

+//BOUT_ENUM_CLASS(BoundaryFreeExtrapolation, limited, exponential, linear);
+
+template <typename impl>
+class BoundaryRegionIterBase { /// get the index at the last point in domain


warning: the implicit default constructor of the CRTP is publicly accessible; consider making it private and declaring the derived class as friend [bugprone-crtp-constructor-accessibility]

Suggested change

class BoundaryRegionIterBase { /// get the index at the last point in domain

class BoundaryRegionIterBase {

BoundaryRegionIterBase() = default;

/// get the index at the last point in domain

include/bout/boundary_region_iter.hxx:362:

- ; + ;friend impl;

github-actions · 2026-05-26T07:13:31Z

+private:
+  // TODO(dave) make non-const?
+  const BoundaryRegionFCI* region;
+  size_t pos{0};


warning: no header providing "size_t" is directly included [misc-include-cleaner]

include/bout/boundary_region_iter.hxx:2:

- #include <cstdint> + #include <cstddef> + #include <cstdint>

github-actions · 2026-05-26T07:13:31Z

+  BoundaryRegionIterFCI(const BoundaryRegionFCI* reg, bool isstart)
+      : region(reg), pos(isstart ? 0 : reg->bndry_points.size()) {}
+  void setValid(char valid) {
+    const_cast<BoundaryRegionFCI*>(region)->bndry_points[pos].valid = valid;


warning: do not use const_cast to remove const qualifier [cppcoreguidelines-pro-type-const-cast]

{ ^

github-actions · 2026-05-26T07:13:31Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[ind().yp(_off)];

}

;()

github-actions · 2026-05-26T07:13:31Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[ind().yp(_off)];

}

;()

github-actions · 2026-05-26T07:13:31Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[ind().yp(_off)];

}

;()

github-actions

clang-tidy made some suggestions

There were too many comments to post at once. Showing the first 25 out of 60. Check the log or trigger a new build to see more.

github-actions · 2026-05-26T08:36:29Z

+//BOUT_ENUM_CLASS(BoundaryFreeExtrapolation, limited, exponential, linear);
+
+template <typename impl>
+class BoundaryRegionIterBase { /// get the index at the last point in domain


warning: the implicit default constructor of the CRTP is publicly accessible; consider making it private and declaring the derived class as friend [bugprone-crtp-constructor-accessibility]

Suggested change

class BoundaryRegionIterBase { /// get the index at the last point in domain

class BoundaryRegionIterBase {

BoundaryRegionIterBase() = default;

/// get the index at the last point in domain

include/bout/boundary_region_iter.hxx:369:

- ; + ;friend impl;

github-actions · 2026-05-26T08:36:30Z

+  BoutReal extrapolate_boundary_free(const Field3D& f,
+                                     BoundaryFreeExtrapolation mode) const {
+    const auto fac = valid() > 0 ? limitFreeScale(prev(f), current(f), mode)
+                                 : (mode == BoundaryFreeExtrapolation::linear ? 0 : 1);


warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators [readability-avoid-nested-conditional-operator]

) ^

Additional context

include/bout/boundary_region_iter.hxx:251: parent conditional operator here

{ ^

github-actions · 2026-05-26T08:36:30Z

+  }
+
+  void set_free(Field3D& f, BoundaryFreeExtrapolation mode) const {
+    int fac;


warning: variable 'fac' is not initialized [cppcoreguidelines-init-variables]

include/bout/boundary_region_iter.hxx:343:

- ; + = 0;

github-actions · 2026-05-26T08:36:30Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[ind().yp(_off)];

}

;()

github-actions · 2026-05-26T08:36:30Z

+      ASSERT3(valid() > -off - 2);
+    }
+    auto _off = _offset() + off * region->_dir;
+    return f(_off, ind().yp(_off));


warning: '*' has higher precedence than '+'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f(_off, ind().yp(_off));

}

;()

github-actions · 2026-05-26T08:36:31Z

  BoundaryOpPar() = default;
-  BoundaryOpPar(BoundaryRegionPar* region, std::shared_ptr<FieldGenerator> value)
+  BoundaryOpPar(bout::boundary::BoundaryRegionFCI* region,
+                std::shared_ptr<FieldGenerator> value)


warning: no header providing "FieldGenerator" is directly included [misc-include-cleaner]

include/bout/parallel_boundary_op.hxx:10:

- #include "bout/unused.hxx" + #include "bout/sys/expressionparser.hxx" + #include "bout/unused.hxx"

github-actions · 2026-05-26T08:36:31Z

+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region, Field3D* value)
+      : bndryX(region), field_values(value), value_type(ValueType::FIELD) {}
+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region, BoutReal value)
+      : bndryX(region), real_value(value), value_type(ValueType::REAL) {}


warning: member initializer for 'value_type' is redundant [cppcoreguidelines-use-default-member-init]

Suggested change

: bndryX(region), real_value(value), value_type(ValueType::REAL) {}

: bndryX(region), real_value(value), {}

github-actions · 2026-05-26T08:36:31Z

+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region, BoutReal value)
+      : bndryX(region), real_value(value), value_type(ValueType::REAL) {}
+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region)
+      : bndryX(region), real_value(0.), value_type(ValueType::REAL) {}


warning: member initializer for 'real_value' is redundant [cppcoreguidelines-use-default-member-init]

Suggested change

: bndryX(region), real_value(0.), value_type(ValueType::REAL) {}

: bndryX(region), , value_type(ValueType::REAL) {}

github-actions · 2026-05-26T08:36:31Z

+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region, BoutReal value)
+      : bndryX(region), real_value(value), value_type(ValueType::REAL) {}
+  BoundaryOpPar(bout::boundary::BoundaryRegionX* region)
+      : bndryX(region), real_value(0.), value_type(ValueType::REAL) {}


warning: member initializer for 'value_type' is redundant [cppcoreguidelines-use-default-member-init]

Suggested change

: bndryX(region), real_value(0.), value_type(ValueType::REAL) {}

: bndryX(region), real_value(0.), {}

github-actions · 2026-05-26T08:36:31Z

+  BoundaryOpPar(BoundaryOpPar* region, Field3D* value)
+      : bndry(region->bndry), field_values(value), value_type(ValueType::FIELD) {}
+  BoundaryOpPar(BoundaryOpPar* region, BoutReal value)
+      : bndry(region->bndry), real_value(value), value_type(ValueType::REAL) {}


warning: member initializer for 'value_type' is redundant [cppcoreguidelines-use-default-member-init]

Suggested change

: bndry(region->bndry), real_value(value), value_type(ValueType::REAL) {}

: bndry(region->bndry), real_value(value), {}

This is required to enable staggering support

github-actions

clang-tidy made some suggestions

There were too many comments to post at once. Showing the first 25 out of 50. Check the log or trigger a new build to see more.

github-actions · 2026-05-26T10:28:50Z

+//BOUT_ENUM_CLASS(BoundaryFreeExtrapolation, limited, exponential, linear);
+
+template <typename impl>
+class BoundaryRegionIterBase { /// get the index at the last point in domain


warning: the implicit default constructor of the CRTP is publicly accessible; consider making it private and declaring the derived class as friend [bugprone-crtp-constructor-accessibility]

Suggested change

class BoundaryRegionIterBase { /// get the index at the last point in domain

class BoundaryRegionIterBase {

BoundaryRegionIterBase() = default;

/// get the index at the last point in domain

include/bout/boundary_region_iter.hxx:374:

- ; + ;friend impl;

github-actions · 2026-05-26T10:28:51Z

+  BoutReal extrapolate_boundary_free(const Field3D& f,
+                                     BoundaryFreeExtrapolation mode) const {
+    const auto fac = valid() > 0 ? limitFreeScale(prev(f), current(f), mode)
+                                 : (mode == BoundaryFreeExtrapolation::linear ? 0 : 1);


warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators [readability-avoid-nested-conditional-operator]

) ^

Additional context

include/bout/boundary_region_iter.hxx:256: parent conditional operator here

{ ^

github-actions · 2026-05-26T10:28:51Z

+  }
+
+  void set_free(Field3D& f, BoundaryFreeExtrapolation mode) const {
+    int fac;


warning: variable 'fac' is not initialized [cppcoreguidelines-init-variables]

include/bout/boundary_region_iter.hxx:348:

- ; + = 0;

github-actions · 2026-05-26T10:28:51Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[_ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[_ind().yp(_off)];

}

;()

github-actions · 2026-05-26T10:28:51Z

+      ASSERT3(_valid() > -off - 2);
+    }
+    auto _off = _offset() - off * region->_dir;
+    return f.ynext(_off)[_ind().yp(_off)];


warning: '*' has higher precedence than '-'; add parentheses to explicitly specify the order of operations [readability-math-missing-parentheses]

Suggested change

return f.ynext(_off)[_ind().yp(_off)];

}

;()

github-actions · 2026-05-26T10:28:52Z

+  }
+
+  BoundaryOpPar* clone(bout::boundary::BoundaryRegionX* region, Field3D* f) override {
+    return new T(region, f);


warning: returning a newly created resource of type 'BoundaryOpPar *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>' [cppcoreguidelines-owning-memory]

return new T(region, f); ^

github-actions · 2026-05-26T10:28:52Z

+    if (!args.empty()) {
+      try {
+        real_value = stringToReal(args.front());
+        return new T(region, real_value);


warning: returning a newly created resource of type 'BoundaryOpPar *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>' [cppcoreguidelines-owning-memory]

return new T(region, real_value); ^

github-actions · 2026-05-26T10:28:52Z

+  }
+
+  BoundaryOpPar* clone(bout::boundary::BoundaryRegionY* region, Field3D* f) override {
+    return new T(region, f);


warning: returning a newly created resource of type 'BoundaryOpPar *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>' [cppcoreguidelines-owning-memory]

return new T(region, f); ^

github-actions · 2026-05-26T10:28:52Z

-  const int dir;
+  BoutReal extrapolate_sheath_free(const Field3D& f, SheathLimitMode mode) const {
+    const auto fac = valid() > 0 ? limitFreeScale(yprev(f), ythis(f), mode)
+                                 : (mode == SheathLimitMode::linear_free ? 0 : 1);


warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators [readability-avoid-nested-conditional-operator]

: (mode == SheathLimitMode::linear_free ? 0 : 1); ^

Additional context

include/bout/parallel_boundary_region.hxx:301: parent conditional operator here

const auto fac = valid() > 0 ? limitFreeScale(yprev(f), ythis(f), mode) ^

github-actions · 2026-05-26T10:28:52Z

+
+  void set_free(Field3D& f, SheathLimitMode mode) const {
+    const auto fac = valid() > 0 ? limitFreeScale(yprev(f), ythis(f), mode)
+                                 : (mode == SheathLimitMode::linear_free ? 0 : 1);


warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators [readability-avoid-nested-conditional-operator]

: (mode == SheathLimitMode::linear_free ? 0 : 1); ^

Additional context

include/bout/parallel_boundary_region.hxx:309: parent conditional operator here

const auto fac = valid() > 0 ? limitFreeScale(yprev(f), ythis(f), mode) ^

github-actions Bot reviewed Mar 5, 2026

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github-actions Bot reviewed Mar 9, 2026

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dschwoerer added 27 commits March 10, 2026 08:17

Move stencils to separte header

ae1f285

Makes it easier to reuse for other code

Add basic boundary region iterator

b9b42ff

Mimicks the parallel case, to write FCI independent code

Provide a new boundary iterator based on RangeIterator

9bdfef5

The boundary region does not match what is done for the parallel case, thus porting it to a iterator does not work.

Only check hasBndry*Y if they would be included

c51a85f

hasBndryUpperY / hasBndryLowerY does not work for FCI and thus the request does not make sense / can be configured to throw. Thus it should not be checked if it is not needed.

ensure we dont mix non-fci BCs with fci

06d581b

rename to include order

7f1d26f

Fix: remove broken code

84f8c83

BoundaryRegionIter has been delted

Convert test to new iterator scheeme

ea05bae

Add Field2D version for 2D metrics

17f8efa

Add setYPrevIfValid

0db3052

Add offset to parallel boundary region

d2f2cc8

This allows to extend the boundary code to place the boundary further away from the boundary.

Add function to check wehther point is in the boundary

1f48a59

Add setValid to BoundaryRegionParIterBase

4af5a4d

Reimplement ynext for the boundary region

e5fbcaf

This is more general and takes the offset() into account, and thus works for cases where the boundary is between the first and second guard cell

Fix extrapolaton / interpolation

ef7b03d

Fix parallel boundary to interpolate into the boundary

6dba751

Previously only the first boundary point was set

Ensure data is sorted

f105c3f

Calculate valid for the general case

f7c1aca

fix parallel neumann BC

55bdbcf

Add limitFree

6f40b4e

Taken from hermes-3, adopted for higher order

add setAll to parallel BC

36c1f94

Move yboundary iterator from hermes to BOUT++

c7cbf11

This allows to write code for FCI and non-FCI using templates.

Add iter_pnts function

f9cad29

Directly iterate over the points

Add example on how to replace RangeIterator with YBoundary

e6f004b

Move documentation to sphinx

3a0f214

Fix iter_pnts

4e21aac

Add more documentation on YBoundary

3a850b1

dschwoerer added 14 commits April 29, 2026 07:59

Fix return type

da4ea6a

Derive from BoundaryRegionBase

84c7f7e

Switch to bout::boundary::BoundaryRegionFCI

4880e01

Do not copy

5fb45f6

Avoid some warnings

9c7b904

Ensure isParallel is set

51fc4aa

Use system cpptrace on fedora

9faef5c

fix sign error

490d054

Add BoundaryRegionX

3423236

Add BoundaryRegionIterX implementation

628e2f8

Restore removed region RGN_ZGUARDS and RGN_YGUARDS

760eef0

CI: Use boutproject build images

2da3c72

Merge remote-tracking branch 'origin/next' into new-par-bc-unified

05e450a

CI: container is called main

8e7ff2d

github-actions Bot reviewed May 26, 2026

View reviewed changes

dschwoerer added 7 commits May 26, 2026 10:13

Add begin/end for bout::boundary::BoundaryRegionIterX

df759a0

Convert apply_stencil to template

9701b99

Add getValue for bout::boundary::BoundaryRegionIterX

c599518

Add used headers

49568f0

Add iteration over bndryX

f1c4deb

t is currently not used

d178919

add ctors and clone for bout::boundary::BoundaryRegionX

1632763

github-actions Bot reviewed May 26, 2026

View reviewed changes

dschwoerer added 4 commits May 26, 2026 11:30

Add location to length

9bdcf80

This is required to enable staggering support

Do call _ind() directly

7b1d5b2

Add BoundaryRegionY as template

b286543

add BoundaryOpPar bits for bout::boundary::BoundaryRegionY

7273724

github-actions Bot reviewed May 26, 2026

View reviewed changes

dschwoerer added 2 commits May 26, 2026 13:12

Use local version

f3bfa30

Allow to distinguish X and Y boundaries

c291f6e

	: bndryX(region), real_value(value), value_type(ValueType::REAL) {}
	: bndryX(region), real_value(value), {}

	: bndryX(region), real_value(0.), value_type(ValueType::REAL) {}
	: bndryX(region), , value_type(ValueType::REAL) {}

	: bndryX(region), real_value(0.), value_type(ValueType::REAL) {}
	: bndryX(region), real_value(0.), {}

	: bndry(region->bndry), real_value(value), value_type(ValueType::REAL) {}
	: bndry(region->bndry), real_value(value), {}

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dschwoerer commented Mar 5, 2026

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