MAINT: Improve performance of internal polynomial operations

numpy · eendebakpt · Aug 24, 2023 · Aug 24, 2023 · Aug 24, 2023 · Aug 24, 2023
commit 57a5c8715fef6568f64151227eee07b38e9ae3b3
diff --git a/numpy/polynomial/_polybase.py b/numpy/polynomial/_polybase.py
@@ -289,47 +289,52 @@ class as self with identical domain and window. If so,
             When `other` is an incompatible instance of ABCPolyBase.
 
         """
-        if isinstance(other, ABCPolyBase):
-            if not isinstance(other, self.__class__):
-                raise TypeError("Polynomial types differ")
-            elif not np.all(self.domain == other.domain):
+        if isinstance(other, self.__class__):
+            if not (self.domain == other.domain).all():
                 raise TypeError("Domains differ")
-            elif not np.all(self.window == other.window):
+            elif not (self.window == other.window).all():
                 raise TypeError("Windows differ")
             elif self.symbol != other.symbol:
                 raise ValueError("Polynomial symbols differ")
             return other.coef
+        elif isinstance(other, ABCPolyBase):
+            raise TypeError("Polynomial types differ")
         return other
 
-    def __init__(self, coef, domain=None, window=None, symbol='x'):
-        [coef] = pu.as_series([coef], trim=False)
-        self.coef = coef
+    def __init__(self, coef, domain=None, window=None, symbol='x', _validate_input = True):
+        if _validate_input:
+            [coef] = pu.as_series([coef], trim=False)
 
-        if domain is not None:
-            [domain] = pu.as_series([domain], trim=False)
-            if len(domain) != 2:
-                raise ValueError("Domain has wrong number of elements.")
-            self.domain = domain
+            if domain is not None:
+                [domain] = pu.as_series([domain], trim=False)
+                if len(domain) != 2:
+                    raise ValueError("Domain has wrong number of elements.")
+                self.domain = domain
 
-        if window is not None:
-            [window] = pu.as_series([window], trim=False)
-            if len(window) != 2:
-                raise ValueError("Window has wrong number of elements.")
-            self.window = window
+            if window is not None:
+                [window] = pu.as_series([window], trim=False)
+                if len(window) != 2:
+                    raise ValueError("Window has wrong number of elements.")
+                self.window = window
 
-        # Validation for symbol
-        try:
-            if not symbol.isidentifier():
-                raise ValueError(
-                    "Symbol string must be a valid Python identifier"
-                )
-        # If a user passes in something other than a string, the above
-        # results in an AttributeError. Catch this and raise a more
-        # informative exception
-        except AttributeError:
-            raise TypeError("Symbol must be a non-empty string")
+            # Validation for symbol
+            try:
+                if not symbol.isidentifier():
+                    raise ValueError(
+                        "Symbol string must be a valid Python identifier"
+                    )
+            # If a user passes in something other than a string, the above
+            # results in an AttributeError. Catch this and raise a more
+            # informative exception
+            except AttributeError:
+                raise TypeError("Symbol must be a non-empty string")
+        else:
+            coef = np.array(coef)
+            self.domain = np.array(domain)
+            self.window = np.array(window)
 
         self._symbol = symbol
+        self.coef = coef
 
     def __repr__(self):
         coef = repr(self.coef)[6:-1]
@@ -521,7 +526,7 @@ def __len__(self):
 
     def __neg__(self):
         return self.__class__(
-            -self.coef, self.domain, self.window, self.symbol
+            -self.coef, self.domain, self.window, self.symbol, _validate_input=False,
         )
 
     def __pos__(self):
@@ -533,23 +538,23 @@ def __add__(self, other):
             coef = self._add(self.coef, othercoef)
         except Exception:
             return NotImplemented
-        return self.__class__(coef, self.domain, self.window, self.symbol)
+        return self.__class__(coef, self.domain, self.window, self.symbol, _validate_input = False)
 
     def __sub__(self, other):
         othercoef = self._get_coefficients(other)
         try:
             coef = self._sub(self.coef, othercoef)
         except Exception:
             return NotImplemented
-        return self.__class__(coef, self.domain, self.window, self.symbol)
+        return self.__class__(coef, self.domain, self.window, self.symbol, _validate_input = False)
 
     def __mul__(self, other):
         othercoef = self._get_coefficients(other)
         try:
             coef = self._mul(self.coef, othercoef)
         except Exception:
             return NotImplemented
-        return self.__class__(coef, self.domain, self.window, self.symbol)
+        return self.__class__(coef, self.domain, self.window, self.symbol, _validate_input = False)
 
     def __truediv__(self, other):
         # there is no true divide if the rhs is not a Number, although it

diff --git a/numpy/polynomial/polynomial.py b/numpy/polynomial/polynomial.py
@@ -314,10 +314,10 @@ def polymulx(c):
 
     """
     # c is a trimmed copy
-    [c] = pu.as_series([c])
+    [c] = pu.as_series([c], copy=False)
     # The zero series needs special treatment
     if len(c) == 1 and c[0] == 0:
-        return c
+        return np.array(c)
 
     prd = np.empty(len(c) + 1, dtype=c.dtype)
     prd[0] = c[0]*0
@@ -358,7 +358,7 @@ def polymul(c1, c2):
 
     """
     # c1, c2 are trimmed copies
-    [c1, c2] = pu.as_series([c1, c2])
+    [c1, c2] = pu.as_series([c1, c2], copy=False)
     ret = np.convolve(c1, c2)
     return pu.trimseq(ret)
 

diff --git a/numpy/polynomial/polyutils.py b/numpy/polynomial/polyutils.py
@@ -26,6 +26,9 @@
 
 from numpy._core.multiarray import dragon4_positional, dragon4_scientific
 from numpy.exceptions import RankWarning
+from numpy.dtypes import ObjectDType
+
+_object_dtype = ObjectDType()
 
 __all__ = [
     'as_series', 'trimseq', 'trimcoef', 'getdomain', 'mapdomain', 'mapparms',
@@ -63,7 +66,7 @@ def trimseq(seq):
         return seq[:i+1]
 
 
-def as_series(alist, trim=True):
+def as_series(alist, trim=True, _validate_input=True, copy=True):
     """
     Return argument as a list of 1-d arrays.
 
@@ -113,19 +116,22 @@ def as_series(alist, trim=True):
     [array([2.]), array([1.1, 0. ])]
 
     """
-    arrays = [np.array(a, ndmin=1, copy=False) for a in alist]
-    if min([a.size for a in arrays]) == 0:
-        raise ValueError("Coefficient array is empty")
-    if any(a.ndim != 1 for a in arrays):
-        raise ValueError("Coefficient array is not 1-d")
+    if _validate_input:
+        arrays = [np.array(a, ndmin=1, copy=False) for a in alist]
+        if min([a.size for a in arrays]) == 0:
+            raise ValueError("Coefficient array is empty")
+        if any(a.ndim != 1 for a in arrays):
+            raise ValueError("Coefficient array is not 1-d")
+    else:
+        arrays = alist
     if trim:
         arrays = [trimseq(a) for a in arrays]
 
-    if any(a.dtype == np.dtype(object) for a in arrays):
+    if any(a.dtype == _object_dtype for a in arrays):
         ret = []
         for a in arrays:
-            if a.dtype != np.dtype(object):
-                tmp = np.empty(len(a), dtype=np.dtype(object))
+            if a.dtype != _object_dtype:
+                tmp = np.empty(len(a), dtype=_object_dtype)
                 tmp[:] = a[:]
                 ret.append(tmp)
             else:
@@ -135,7 +141,7 @@ def as_series(alist, trim=True):
             dtype = np.common_type(*arrays)
         except Exception as e:
             raise ValueError("Coefficient arrays have no common type") from e
-        ret = [np.array(a, copy=True, dtype=dtype) for a in arrays]
+        ret = [np.array(a, copy=copy, dtype=dtype) for a in arrays]
     return ret