simplify tidy

.clang-tidy

@@ -1,4 +1,4 @@
-# Copyright 2020-2024 Alfredo A. Correa
+# Copyright 2020-2025 Alfredo A. Correa
 
 WarningsAsErrors: '*'
 HeaderFilterRegex: '.'
@@ -22,38 +22,33 @@ CheckOptions:
   - { key: readability-identifier-naming.TemplateParameterCase             , value: CamelCase  }
   - { key: readability-identifier-naming.TypeTemplateParameterIgnoredRegexp, value: expr-type}
   - { key: readability-operators-representation.BinaryOperators            , value: '&&;&=;&;|;~;!;!=;||;|=;^;^='}
-# value: expr-type , bug in clang 16 in c++20 mode https://stackoverflow.com/a/75157215/225186
-
-# for range-for loops, e.g. `for(auto i : is) ...`
-#  - { key: readability-identifier-length.IgnoredVariableNames        , value: "^[ijk]$"  }
 
 Checks: '*,
   -altera-struct-pack-align,
   -boost-use-ranges,
   -cppcoreguidelines-avoid-magic-numbers,
   -cppcoreguidelines-macro-usage,
-  -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
-  -fuchsia-overloaded-operator,
   -fuchsia-default-arguments-calls,
+  -fuchsia-overloaded-operator,
   -fuchsia-trailing-return,
-  -hicpp-no-array-decay,
   -llvmlibc-*,
   -modernize-use-nodiscard,
-  -readability-magic-numbers,
-  -readability-simplify-boolean-expr'
+  -readability-magic-numbers'
+
+#  -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
+#  -hicpp-no-array-decay,                                 // for Boost Lightweight Test
+#  -llvm-header-guard,                                    // allow PCH
+#  -misc-include-cleaner                                  // allow PCH
+#  readability-simplify-boolean-expr,                     // for Boost Lightweight Test BOOST_TEST
+
 ## explanation of the suppressed rules above:
 #  -altera-struct-pack-align,                             // this asks to use non-standard pragmas such as __attribute__((aligned(0))) and _attribute__((packed)), may interfeere with gcc/nvcc compatibility?
 #  -boost-use-ranges                                      // would introduce a dependency on Boost
-#  -clang-diagnostic-deprecated-declarations              // some test run deprecated functions on purpose
 #  -cppcoreguidelines-avoid-magic-numbers,                // all tests use magic numbers
-#  -cppcoreguidelines-pro-bounds-array-to-pointer-decay   // for Boost Lightweight test BOOST_TEST
 #  -cppcoreguidelines-macro-usage,                        // BLAS adaptors uses a lot of macros
 #  -fuchsia-default-arguments-calls,                      // this library uses STL functions, which use default arguments
 #  -fuchsia-overloaded-operator,                          // this library overloads operators (==, <, +, &)
-#  -hicpp-no-array-decay,                                 // for Boost Lightweight Test
+#. -fuchsia-trailing-return,                              // asks all functions to be pure 'auto'
 #  -llvmlibc-*,                                           // nonsense warnings, for llvm developers
-#  -llvm-header-guard,                                    // allow PCH
-#  -misc-include-cleaner                                  // allow PCH
 #  -modernize-use-nodiscard,                              // this would add [[nodiscard]] to almost all functions, adding a lot of noise
 #  -readability-magic-numbers,                            // many tests use magic numbers
-#  readability-simplify-boolean-expr,                     // for Boost Lightweight Test BOOST_TEST