Math.gcd new function

.github/workflows/ports_qemu-arm.yml

@@ -18,6 +18,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_qemu_arm_setup
     - name: Build and run test suite

.github/workflows/ports_unix.yml

@@ -41,6 +41,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_standard_build
     - name: Run main test suite
@@ -53,6 +56,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_dev_build
     - name: Run main test suite
@@ -65,8 +71,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Install packages
-      run: source tools/ci.sh && ci_unix_coverage_setup
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
+    - name: Install python dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install setuptools pyelftools
+    - name: Print environment version
+      run: source tools/ci.sh && ci_unix_coverage_print_env
     - name: Build
       run: source tools/ci.sh && ci_unix_coverage_build
     - name: Run main test suite
@@ -92,6 +105,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
+    - name: Install python dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install setuptools pyelftools
     - name: Install packages
       run: source tools/ci.sh && ci_unix_32bit_setup
     - name: Build
@@ -110,6 +130,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_unix_32bit_setup
     - name: Build
@@ -124,6 +147,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_float_build
     - name: Run main test suite
@@ -136,6 +162,9 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_unix_clang_setup
     - name: Build
@@ -150,6 +179,9 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_unix_clang_setup
     - name: Build
@@ -164,6 +196,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_settrace_build
     - name: Run main test suite
@@ -176,6 +211,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_settrace_stackless_build
     - name: Run main test suite
@@ -190,7 +228,7 @@ jobs:
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v2
       with:
-        python-version: '3.8'
+        python-version: '3.9'
     - name: Build
       run: source tools/ci.sh && ci_unix_macos_build
     - name: Run tests
@@ -203,6 +241,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_unix_qemu_mips_setup
     - name: Build
@@ -217,6 +258,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
     - name: Install packages
       run: source tools/ci.sh && ci_unix_qemu_arm_setup
     - name: Build

docs/differences/python_35.rst

@@ -101,7 +101,7 @@ Changes to built-in modules:
    +-----------------------------------------------------------------------------------------------------------+---------------+
    | A new function *isclose()* provides a way to test for approximate equality.                               |               |
    +-----------------------------------------------------------------------------------------------------------+---------------+
-   | A new *gcd()* function has been added. The *fractions.gcd()* function is now deprecated.                  |               |
+   | A new *gcd()* function has been added. The *fractions.gcd()* function is now deprecated.                  | Completed     |
    +-----------------------------------------------------------------------------------------------------------+---------------+
    | `os <https://docs.python.org/3/whatsnew/3.5.html#os>`_                                                                    |
    +-----------------------------------------------------------------------------------------------------------+---------------+

docs/differences/python_39.rst

@@ -90,7 +90,7 @@ Changes to built-in modules:
   +---------------------------------------------------------------------------------------------------------------+---------------+
   | `math`                                                                                                                        |
   +---------------------------------------------------------------------------------------------------------------+---------------+
-  | Expanded the *math.gcd()* function to handle multiple arguments. Formerly, it only supported two arguments    |               |
+  | Expanded the *math.gcd()* function to handle multiple arguments. Formerly, it only supported two arguments    | Completed     |
   +---------------------------------------------------------------------------------------------------------------+---------------+
   | Added *math.lcm()*: return the least common multiple of specified arguments                                   |               |
   +---------------------------------------------------------------------------------------------------------------+---------------+

docs/library/math.rst

@@ -104,6 +104,10 @@ Functions
 
    Return the gamma function of ``x``.
 
+.. function:: gcd(x, y, ...)
+
+   Return the greatest common divisor of any amount of numbers with minimum of 2 arguments.
+
 .. function:: isfinite(x)
 
    Return ``True`` if ``x`` is finite.

ports/windows/.appveyor.yml

@@ -1,10 +1,10 @@
-image: Visual Studio 2017
+image: Visual Studio 2019
 clone_depth: 1
 skip_tags: true
 
 environment:
   # Python version used
-  MICROPY_CPYTHON3: c:/python38/python.exe
+  MICROPY_CPYTHON3: c:/python39/python.exe
   # The variants.
   matrix:
     - PyVariant: dev

py/modmath.c

@@ -199,7 +199,61 @@ MATH_FUN_1(erfc, erfc)
 MATH_FUN_1(gamma, tgamma)
 // lgamma(x): return the natural logarithm of the gamma function of x
 MATH_FUN_1(lgamma, lgamma)
-#endif
+
+/* gcd(x, y): return the greatest common divisor
+ GCD Pseudocode
+  * gcd(x,y)
+  * if x < y;
+  * x, y = y, x
+  *
+  * while y != 0:
+  *  x,y = y, x mod y
+  * return x
+*/
+STATIC mp_obj_t gcd_func(mp_obj_t x, mp_obj_t y) {
+    mp_obj_t temp;
+    if (mp_binary_op(MP_BINARY_OP_LESS, x, y) == mp_const_true) {
+        temp = x;
+        x = y;
+        y = temp;
+    }
+
+    mp_obj_t zero = mp_obj_new_int(0);
+    while (mp_binary_op(MP_BINARY_OP_NOT_EQUAL, y, zero) == mp_const_true) {
+        temp = y;
+        y = mp_binary_op(MP_BINARY_OP_MODULO, x, y);
+        x = temp;
+    }
+    return x;
+}
+
+STATIC mp_obj_t gcd_preprocess_arg(mp_obj_t presumed_integer) {
+    if (!mp_obj_is_int(presumed_integer)) {
+        mp_raise_msg_varg(&mp_type_TypeError,
+            MP_ERROR_TEXT("can't convert %s to int"), mp_obj_get_type_str(presumed_integer));
+    }
+    return mp_unary_op(MP_UNARY_OP_ABS, presumed_integer);
+}
+
+STATIC mp_obj_t mp_math_gcd(size_t n_args, const mp_obj_t *args) {
+    mp_obj_t e = gcd_preprocess_arg(args[--n_args]);
+    mp_obj_t d = gcd_preprocess_arg(args[--n_args]);
+
+    mp_obj_t ans = gcd_func(d, e);
+    if (n_args == 0) {
+        return ans;
+    }
+
+    // gcd(a, gcd(b, gcd(c, gcd(d, e)))))
+    do {
+        mp_obj_t next_variable = gcd_preprocess_arg(args[--n_args]);
+        ans = gcd_func(next_variable, ans);
+    } while (n_args > 0);
+    return ans;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR(mp_math_gcd_obj, 2, mp_math_gcd);
+
+#endif // MICROPY_PY_MATH_SPECIAL_FUNCTIONS
 // TODO: fsum
 
 #if MICROPY_PY_MATH_ISCLOSE
@@ -425,6 +479,7 @@ STATIC const mp_rom_map_elem_t mp_module_math_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_erfc), MP_ROM_PTR(&mp_math_erfc_obj) },
     { MP_ROM_QSTR(MP_QSTR_gamma), MP_ROM_PTR(&mp_math_gamma_obj) },
     { MP_ROM_QSTR(MP_QSTR_lgamma), MP_ROM_PTR(&mp_math_lgamma_obj) },
+    { MP_ROM_QSTR(MP_QSTR_gcd), MP_ROM_PTR(&mp_math_gcd_obj) },
     #endif
 };
 

tests/float/math_fun_special.py

@@ -50,3 +50,57 @@
             print("{:.4g}".format(function(value)))
         except ValueError as e:
             print(str(e))
+
+
+# Tests for gcd mostly duplicated from
+# https://github.com/python/cpython/blob/main/Lib/test/test_math.py
+
+
+def assertRaises(exception, func, *args):
+    try:
+        print(func(*args))
+        assert False
+    except exception:
+        pass
+
+
+print(gcd(0, 0))
+print(gcd(1, 0))
+print(gcd(-1, 0))
+print(gcd(0, 1))
+print(gcd(0, -1))
+print(gcd(7, 1))
+print(gcd(7, -1))
+print(gcd(-23, 15))
+print(gcd(120, 84))
+print(gcd(84, -120))
+print(gcd(1216342683557601535506311712, 436522681849110124616458784))
+
+x = 434610456570399902378880679233098819019853229470286994367836600566
+y = 1064502245825115327754847244914921553977
+for c in (652560, 576559230871654959816130551884856912003141446781646602790216406874):
+    a = x * c
+    b = y * c
+    print(gcd(a, b))
+    print(gcd(b, a))
+    print(gcd(-a, b))
+    print(gcd(b, -a))
+    print(gcd(a, -b))
+    print(gcd(-b, a))
+    print(gcd(-a, -b))
+    print(gcd(-b, -a))
+
+# In MP minimum argument count is 2
+# self.assertEqual(gcd(), 0)
+# self.assertEqual(gcd(120), 120)
+# self.assertEqual(gcd(-120), 120)
+
+print(gcd(120, 84, 102))
+print(gcd(120, 1, 84))
+print(gcd(6, 30, 40, -60, 20, 40))
+print(gcd(12345678912345678912345678911561561658135153135135135, 123456))
+
+assertRaises(TypeError, gcd, 120.0)
+assertRaises(TypeError, gcd, 120.0, 84)
+assertRaises(TypeError, gcd, 120, 84.0)
+assertRaises(TypeError, gcd, 120, 1, 84.0)

tools/ci.sh

@@ -434,9 +434,7 @@ function ci_unix_dev_run_tests {
     ci_unix_run_tests_helper VARIANT=dev
 }
 
-function ci_unix_coverage_setup {
-    sudo pip3 install setuptools
-    sudo pip3 install pyelftools
+function ci_unix_coverage_print_env {
     gcc --version
     python3 --version
 }
@@ -459,8 +457,6 @@ function ci_unix_32bit_setup {
     sudo dpkg --add-architecture i386
     sudo apt-get update
     sudo apt-get install gcc-multilib g++-multilib libffi-dev:i386
-    sudo pip3 install setuptools
-    sudo pip3 install pyelftools
     gcc --version
     python2 --version
     python3 --version