from_values method for FourierRZCoil and FourierPlanarCoil

CHANGELOG.md

@@ -1,6 +1,11 @@
 Changelog
 =========
 
+New Features
+
+- adds ``from_values`` method that was present in ``FourierRZCurve`` but missing in ``FourierRZCoil``
+- also adds new ``from_values`` method for ``FourierPlanarCurve`` and ``FourierPlanarCoil``
+
 
 v0.12.0
 -------

desc/coils.py

@@ -346,14 +346,83 @@ def to_SplineXYZ(self, knots=None, grid=None, method="cubic", name=""):
             self.current, coords, knots=knots, method=method, name=name, basis="xyz"
         )
 
+    def to_FourierRZ(self, N=10, grid=None, NFP=None, sym=False, name=""):
+        """Convert Coil to FourierRZCoil representation.
+
+        Note that some types of coils may not be representable in this basis.
+
+        Parameters
+        ----------
+        N : int
+            Fourier resolution of the new R,Z representation.
+        grid : Grid, int or None
+            Grid used to evaluate curve coordinates on to fit with FourierRZCoil.
+            If an integer, uses that many equally spaced points.
+        NFP : int
+            Number of field periods, the coil will have a discrete toroidal symmetry
+            according to NFP.
+        sym : bool, optional
+            whether the curve is stellarator-symmetric or not. Default
+            is False.
+        name : str
+            name for this coil
+
+        Returns
+        -------
+        curve : FourierRZCoil
+            New representation of the coil parameterized by Fourier series for R,Z.
+
+        """
+        NFP = 1 or NFP
+        if grid is None:
+            grid = LinearGrid(N=2 * N + 1)
+        coords = self.compute("x", grid=grid, basis="xyz")["x"]
+        return FourierRZCoil.from_values(
+            self.current, coords, N=N, NFP=NFP, basis="xyz", sym=sym, name=name
+        )
+
+    def to_FourierPlanar(self, N=10, grid=None, basis="xyz", name=""):
+        """Convert Coil to FourierPlanarCoil representation.
+
+        Note that some types of coils may not be representable in this basis.
+        In this case, a least-squares fit will be done to find the
+        planar coil that best represents the coil.
+
+        Parameters
+        ----------
+        N : int
+            Fourier resolution of the new FourierPlanarCoil representation.
+        grid : Grid, int or None
+            Grid used to evaluate curve coordinates on to fit with FourierPlanarCoil.
+            If an integer, uses that many equally spaced points.
+        basis : {'xyz', 'rpz'}
+            Coordinate system for center and normal vectors. Default = 'xyz'.
+        name : str
+            name for this coil
+
+        Returns
+        -------
+        coil : FourierPlanarCoil
+            New representation of the coil parameterized by Fourier series for
+            minor radius r in a plane specified by a center position and normal
+            vector.
+
+        """
+        if grid is None:
+            grid = LinearGrid(N=2 * N + 1)
+        coords = self.compute("x", grid=grid, basis=basis)["x"]
+        return FourierPlanarCoil.from_values(
+            self.current, coords, N=N, basis=basis, name=name
+        )
+
 
 class FourierRZCoil(_Coil, FourierRZCurve):
     """Coil parameterized by fourier series for R,Z in terms of toroidal angle phi.
 
     Parameters
     ----------
     current : float
-        current through coil, in Amperes
+        Current through the coil, in Amperes.
     R_n, Z_n: array-like
         fourier coefficients for R, Z
     modes_R : array-like
@@ -414,14 +483,58 @@ def __init__(
     ):
         super().__init__(current, R_n, Z_n, modes_R, modes_Z, NFP, sym, name)
 
+    @classmethod
+    def from_values(cls, current, coords, N=10, NFP=1, basis="rpz", sym=False, name=""):
+        """Fit coordinates to FourierRZCoil representation.
+
+        Parameters
+        ----------
+        current : float
+            Current through the coil, in Amperes.
+        coords: ndarray, shape (num_coords,3)
+            coordinates to fit a FourierRZCurve object with each column
+            corresponding to xyz or rpz depending on the basis argument.
+        N : int
+            Fourier resolution of the new R,Z representation.
+        NFP : int
+            Number of field periods, the curve will have a discrete toroidal symmetry
+            according to NFP.
+        basis : {"rpz", "xyz"}
+            basis for input coordinates. Defaults to "rpz"
+        sym : bool
+            Whether to enforce stellarator symmetry.
+        name : str
+            name for this coil
+
+
+        Returns
+        -------
+        coil : FourierRZCoil
+            New representation of the coil parameterized by Fourier series for R,Z.
+
+        """
+        curve = super().from_values(
+            coords=coords, N=N, NFP=NFP, basis=basis, sym=sym, name=name
+        )
+        return FourierRZCoil(
+            current=current,
+            R_n=curve.R_n,
+            Z_n=curve.Z_n,
+            modes_R=curve.R_basis.modes[:, 2],
+            modes_Z=curve.Z_basis.modes[:, 2],
+            NFP=NFP,
+            sym=curve.sym,
+            name=name,
+        )
+
 
 class FourierXYZCoil(_Coil, FourierXYZCurve):
     """Coil parameterized by fourier series for X,Y,Z in terms of arbitrary angle s.
 
     Parameters
     ----------
     current : float
-        current through coil, in Amperes
+        Current through the coil, in Amperes.
     X_n, Y_n, Z_n: array-like
         fourier coefficients for X, Y, Z
     modes : array-like
@@ -484,7 +597,7 @@ def from_values(cls, current, coords, N=10, s=None, basis="xyz", name=""):
         Parameters
         ----------
         current : float
-            Current through the coil, in Amps.
+            Current through the coil, in Amperes.
         coords: ndarray
             Coordinates to fit a FourierXYZCoil object with.
         N : int
@@ -503,12 +616,13 @@ def from_values(cls, current, coords, N=10, s=None, basis="xyz", name=""):
             New representation of the coil parameterized by Fourier series for X,Y,Z.
 
         """
-        curve = super().from_values(coords, N, s, basis)
-        return cls(
-            current,
+        curve = super().from_values(coords=coords, N=N, s=s, basis=basis, name=name)
+        return FourierXYZCoil(
+            current=current,
             X_n=curve.X_n,
             Y_n=curve.Y_n,
             Z_n=curve.Z_n,
+            modes=curve.X_basis.modes[:, 2],
             name=name,
         )
 
@@ -586,14 +700,49 @@ def __init__(
     ):
         super().__init__(current, center, normal, r_n, modes, basis, name)
 
+    @classmethod
+    def from_values(cls, current, coords, N=10, basis="xyz", name=""):
+        """Fit coordinates to FourierPlanarCoil representation.
+
+        Parameters
+        ----------
+        current : float
+            Current through the coil, in Amperes.
+        coords: ndarray, shape (num_coords,3)
+            Coordinates to fit a FourierPlanarCurve object with each column
+            corresponding to xyz or rpz depending on the basis argument.
+        N : int
+            Fourier resolution of the new r representation.
+        basis : {"rpz", "xyz"}
+            Basis for input coordinates. Defaults to "xyz".
+        name : str
+            Name for this curve.
+
+        Returns
+        -------
+        curve : FourierPlanarCoil
+            New representation of the coil parameterized by a Fourier series for r.
+
+        """
+        curve = super().from_values(coords=coords, N=N, basis=basis, name=name)
+        return FourierPlanarCoil(
+            current=current,
+            center=curve.center,
+            normal=curve.normal,
+            r_n=curve.r_n,
+            modes=curve.r_basis.modes[:, 2],
+            basis="xyz",
+            name=name,
+        )
+
 
 class SplineXYZCoil(_Coil, SplineXYZCurve):
     """Coil parameterized by spline points in X,Y,Z.
 
     Parameters
     ----------
     current : float
-        current through coil, in Amperes
+        Current through the coil, in Amperes.
     X, Y, Z: array-like
         Points for X, Y, Z describing the curve. If the endpoint is included
         (ie, X[0] == X[-1]), then the final point will be dropped.
@@ -705,7 +854,7 @@ def from_values(
         Parameters
         ----------
         current : float
-            Current through the coil, in Amps.
+            Current through the coil, in Amperes.
         coords: ndarray
             Points for X, Y, Z describing the curve. If the endpoint is included
             (ie, X[0] == X[-1]), then the final point will be dropped.
@@ -737,9 +886,11 @@ def from_values(
             New representation of the coil parameterized by splines in X,Y,Z.
 
         """
-        curve = super().from_values(coords, knots, method, basis=basis)
-        return cls(
-            current,
+        curve = super().from_values(
+            coords=coords, knots=knots, method=method, basis=basis, name=name
+        )
+        return SplineXYZCoil(
+            current=current,
             X=curve.X,
             Y=curve.Y,
             Z=curve.Z,

desc/geometry/core.py

@@ -209,7 +209,7 @@
             + " (name={})".format(self.name)
         )
 
-    def to_FourierXYZ(self, N=None, grid=None, s=None, name=""):
+    def to_FourierXYZ(self, N=10, grid=None, s=None, name=""):
         """Convert Curve to FourierXYZCurve representation.
 
         Parameters
@@ -284,7 +284,7 @@
             coords, knots=knots, method=method, name=name, basis="xyz"
         )
 
-    def to_FourierRZ(self, N=None, grid=None, NFP=None, name=""):
+    def to_FourierRZ(self, N=10, grid=None, NFP=None, sym=False, name=""):
         """Convert Curve to FourierRZCurve representation.
 
         Note that some types of curves may not be representable in this basis.
@@ -299,6 +299,8 @@
         NFP : int
             Number of field periods, the curve will have a discrete toroidal symmetry
             according to NFP.
+        sym : bool, optional
+            Whether the curve is stellarator-symmetric or not. Default is False.
         name : str
             name for this curve
 
@@ -312,9 +314,45 @@
 
         NFP = 1 or NFP
         if grid is None:
-            grid = LinearGrid(N=2 * N + 1, NFP=NFP)
+            grid = LinearGrid(N=2 * N + 1)
         coords = self.compute("x", grid=grid, basis="xyz")["x"]
-        return FourierRZCurve.from_values(coords, N=N, NFP=NFP, basis="xyz", name=name)
+        return FourierRZCurve.from_values(
+            coords, N=N, NFP=NFP, basis="xyz", name=name, sym=sym
+        )
+
+    def to_FourierPlanar(self, N=10, grid=None, basis="xyz", name=""):
+        """Convert Curve to FourierPlanarCurve representation.
+
+        Note that some types of curves may not be representable in this basis.
+        In this case, a least-squares fit will be done to find the
+        planar curve that best represents the curve.
+
+        Parameters
+        ----------
+        N : int
+            Fourier resolution of the new FourierPlanarCurve representation.
+        grid : Grid, int or None
+            Grid used to evaluate curve coordinates on to fit with FourierPlanarCurve.
+            If an integer, uses that many equally spaced points.
+        basis : {'xyz', 'rpz'}
+            Coordinate system for center and normal vectors. Default = 'xyz'.
+        name : str
+            name for this curve
+
+        Returns
+        -------
+        curve : FourierPlanarCurve
+            New representation of the curve parameterized by Fourier series for
+            minor radius r in a plane specified by a center position and normal
+            vector.
+
+        """
+        from .curve import FourierPlanarCurve
+
+        if grid is None:
+            grid = LinearGrid(N=2 * N + 1)
+        coords = self.compute("x", grid=grid, basis=basis)["x"]
+        return FourierPlanarCurve.from_values(coords, N=N, basis=basis, name=name)
 
 
 class Surface(IOAble, Optimizable, ABC):