PERF: Optimize point transformations (#1204)

.pylintrc

@@ -23,4 +23,4 @@ disable=cyclic-import,
 
 
 [FORMAT]
-max-module-lines=1350
+max-module-lines=1500

docs/history.rst

@@ -3,13 +3,11 @@ Change Log
 
 Latest
 ------
-
-3.5.0
------
 - ENH: Add `return_back_azimuth: bool` to allow compatibility between the azimuth output of the following functions (issue #1163):
     `fwd` and `fwd_intermediate`, `inv` and `inv_intermediate`,
     Note: BREAKING CHANGE for the default value `return_back_azimuth=True` in the functions `fwd_intermediate` and `inv_intermediate`
     to mach the default value in `fwd` and `inv`
+- PERF: Optimize point transformations (pull #1204)
 
 3.4.1
 -----

pyproj/_transformer.pyi

@@ -1,3 +1,4 @@
+import numbers
 from array import array
 from typing import Any, List, NamedTuple, Optional, Tuple, Union
 
@@ -96,6 +97,16 @@ class _Transformer(Base):
         radians: bool,
         errcheck: bool,
     ) -> None: ...
+    def _transform_point(
+        self,
+        inx: numbers.Real,
+        iny: numbers.Real,
+        inz: numbers.Real,
+        intime: numbers.Real,
+        direction: Union[TransformDirection, str],
+        radians: bool,
+        errcheck: bool,
+    ) -> None: ...
     def _transform_sequence(
         self,
         stride: int,

pyproj/_transformer.pyx

@@ -718,6 +718,91 @@ cdef class _Transformer(Base):
                     ybuff.data[iii] = ybuff.data[iii]*_DG2RAD
         _clear_proj_error()
 
+    @cython.boundscheck(False)
+    @cython.wraparound(False)
+    def _transform_point(
+        self,
+        object inx,
+        object iny,
+        object inz,
+        object intime,
+        object direction,
+        bint radians,
+        bint errcheck,
+    ):
+        """
+        Optimized to transform a single point between two coordinate systems.
+        """
+        cdef double coord_x = inx
+        cdef double coord_y = iny
+        cdef double coord_z = 0
+        cdef double coord_t = HUGE_VAL
+        cdef tuple expected_numeric_types = (int, float)
+        if not isinstance(inx, expected_numeric_types):
+            raise TypeError("Scalar input expected for x")
+        if not isinstance(iny, expected_numeric_types):
+            raise TypeError("Scalar input expected for y")
+        if inz is not None:
+            if not isinstance(inz, expected_numeric_types):
+                raise TypeError("Scalar input expected for z")
+            coord_z = inz
+        if intime is not None:
+            if not isinstance(intime, expected_numeric_types):
+                raise TypeError("Scalar input expected for t")
+            coord_t = intime
+
+        cdef tuple return_data
+        if self.id == "noop":
+            return_data = (inx, iny)
+            if inz is not None:
+                return_data += (inz,)
+            if intime is not None:
+                return_data += (intime,)
+            return return_data
+
+        cdef PJ_DIRECTION pj_direction = get_pj_direction(direction)
+        cdef PJ_COORD projxyout
+        cdef PJ_COORD projxyin = proj_coord(coord_x, coord_y, coord_z, coord_t)
+        with nogil:
+            # degrees to radians
+            if not radians and proj_angular_input(self.projobj, pj_direction):
+                projxyin.uv.u *= _DG2RAD
+                projxyin.uv.v *= _DG2RAD
+            # radians to degrees
+            elif radians and proj_degree_input(self.projobj, pj_direction):
+                projxyin.uv.u *= _RAD2DG
+                projxyin.uv.v *= _RAD2DG
+
+            proj_errno_reset(self.projobj)
+            projxyout = proj_trans(self.projobj, pj_direction, projxyin)
+            errno = proj_errno(self.projobj)
+            if errcheck and errno:
+                with gil:
+                    raise ProjError(
+                        f"transform error: {proj_context_errno_string(self.context, errno)}"
+                    )
+            elif errcheck:
+                with gil:
+                    if _clear_proj_error() is not None:
+                        raise ProjError("transform error")
+
+            # radians to degrees
+            if not radians and proj_angular_output(self.projobj, pj_direction):
+                projxyout.xy.x *= _RAD2DG
+                projxyout.xy.y *= _RAD2DG
+            # degrees to radians
+            elif radians and proj_degree_output(self.projobj, pj_direction):
+                projxyout.xy.x *= _DG2RAD
+                projxyout.xy.y *= _DG2RAD
+        _clear_proj_error()
+
+        return_data = (projxyout.xyzt.x, projxyout.xyzt.y)
+        if inz is not None:
+            return_data += (projxyout.xyzt.z,)
+        if intime is not None:
+            return_data += (projxyout.xyzt.t,)
+        return return_data
+
     @cython.boundscheck(False)
     @cython.wraparound(False)
     def _transform_sequence(

pyproj/proj.pxi

@@ -99,6 +99,7 @@ cdef extern from "proj.h" nogil:
     int proj_degree_input (PJ *P, PJ_DIRECTION dir)
     int proj_degree_output (PJ *P, PJ_DIRECTION dir)
 
+    PJ_COORD proj_trans (PJ *P, PJ_DIRECTION direction, PJ_COORD coord)
     size_t proj_trans_generic (
         PJ *P,
         PJ_DIRECTION direction,

pyproj/transformer.py

@@ -789,6 +789,19 @@ def transform(  # pylint: disable=invalid-name
         '33  98'
 
         """
+        try:
+            # function optimized for point data
+            return self._transformer._transform_point(
+                inx=xx,
+                iny=yy,
+                inz=zz,
+                intime=tt,
+                direction=direction,
+                radians=radians,
+                errcheck=errcheck,
+            )
+        except TypeError:
+            pass
         # process inputs, making copies that support buffer API.
         inx, x_data_type = _copytobuffer(xx, inplace=inplace)
         iny, y_data_type = _copytobuffer(yy, inplace=inplace)
@@ -802,8 +815,8 @@ def transform(  # pylint: disable=invalid-name
             intime = None
         # call pj_transform.  inx,iny,inz buffers modified in place.
         self._transformer._transform(
-            inx,
-            iny,
+            inx=inx,
+            iny=iny,
             inz=inz,
             intime=intime,
             direction=direction,

test/conftest.py

@@ -3,6 +3,8 @@
 from contextlib import contextmanager
 from pathlib import Path
 
+import numpy
+import pytest
 from packaging import version
 
 import pyproj
@@ -90,3 +92,27 @@ def assert_can_pickle(raw_obj, tmp_path):
         unpickled = pickle.load(f)
 
     assert raw_obj == unpickled
+
+
+def _make_longer_array(data: float):
+    """
+    Turn the float into a 2-element array
+    """
+    return numpy.array([data] * 2)
+
+
+@pytest.fixture(
+    params=[
+        float,
+        numpy.array,
+        _make_longer_array,
+    ]
+)
+def scalar_and_array(request):
+    """
+    Ensure cython methods are tested
+    with scalar and arrays to trigger
+    point optimized functions as well
+    as the main functions supporting arrays.
+    """
+    return request.param