connected_path_from_rlu

docs/src/structure-factor.md

@@ -170,9 +170,9 @@ e.g., `bzsize=(2,2,2)`. The resulting list of wave vectors may then be passed to
 Alternatively, [`intensities_binned`](@ref) can be used to place the exact data
 into histogram bins for comparison with experiment.
 
-The convenience function [`connected_path`](@ref) returns a list of wavevectors
-sampled along a path that connects specified $𝐪$ points. This list can be used
-as an input to `intensities`. Another convenience method,
+The convenience function [`connected_path_from_rlu`](@ref) returns a list of
+wavevectors sampled along a path that connects specified $𝐪$ points. This list
+can be used as an input to `intensities`. Another convenience method,
 [`spherical_shell`](@ref) will provide a list of wave vectors on a sphere of a
 specified radius. This is useful for powder averaging. 
 

examples/fei2_tutorial.jl

@@ -245,29 +245,19 @@ plot_spins(sys_min; arrowlength=2.5, linewidth=0.75, arrowsize=1.5)
 
 swt = SpinWaveTheory(sys_min);
 
-# Next, select a sequence of wavevectors that will define a piecewise linear
-# interpolation in reciprocal lattice units (RLU). Sunny expects wavevectors in
-# absolute units, i.e., inverse angstroms. To convert from RLU, multiply by the
-# $3×3$ matrix `cryst.recipvecs`, which provides the reciprocal lattice vectors
-# for the conventional unit cell.
+# Select a sequence of wavevectors that will define a piecewise linear
+# interpolation in reciprocal lattice units (RLU).
 
 points_rlu = [[0,0,0], [1,0,0], [0,1,0], [1/2,0,0], [0,1,0], [0,0,0]]
-points = [cryst.recipvecs*p for p in points_rlu]
 
-# The function [`connected_path`](@ref) will linearly sample between the
-# provided $q$-points with given `density`. Also keep track of location and
-# names of the special $𝐪$-points for plotting purposes.
+# The function [`connected_path_from_rlu`](@ref) will linearly sample between
+# the provided $q$-points with a given `density`. The `path` return value is a
+# list of wavevectors in absolute units (inverse Å). The `xticks` return value
+# keeps track of the locations of the special $𝐪$-points, and provides
+# human-readable labels for use in plotting.
 
 density = 50
-path, numbers = connected_path(points, density);
-xticks = (numbers, ["[0,0,0]", "[1,0,0]", "[0,1,0]", "[1/2,0,0]", "[0,1,0]", "[0,0,0]"])
-
-# The dispersion relation can be calculated by providing `dispersion` with a
-# `SpinWaveTheory` and a list of wave vectors. For each wave vector,
-# `dispersion` will return a list of energies, one for each band. Frequently one
-# wants dispersion information along lines that connect special wave vectors.
-# The function [`connected_path`](@ref) linearly samples between provided
-# $𝐪$-points, with a given sample density.
+path, xticks = connected_path_from_rlu(cryst, points_rlu, density);
 
 # The [`dispersion`](@ref) function defines the quasiparticle excitation
 # energies $ω_i(𝐪)$ for each point $𝐪$ along the reciprocal space path.
@@ -332,13 +322,13 @@ heatmap!(ax, 1:size(is_averaged, 1), energies, is_averaged)
 fig
 
 # This result can be directly compared to experimental neutron scattering data
-# [Bai et al.](https://doi.org/10.1038/s41567-020-01110-1)
+# from [Bai et al.](https://doi.org/10.1038/s41567-020-01110-1)
 # ```@raw html
 # <img src="https://raw.githubusercontent.com/SunnySuite/Sunny.jl/main/docs/src/assets/FeI2_intensity.jpg">
 # ```
 #
-# (Note that the publication figure uses a different coordinate system to label
-# the wave vectors.)
+# (The publication figure accidentally used a non-standard coordinate system to
+# label the wave vectors.)
 # 
 # To get this agreement, the use of SU(3) coherent states is essential (in other
 # words, we needed a theory of multi-flavored bosons). The lower band has large

examples/longer_examples/CoRh2O4-tutorial.jl

@@ -108,7 +108,7 @@ end
 # ### System Definition for CoRh<sub>2</sub>O<sub>4</sub>
 
 # Define the crystal structure of CoRh$_2$O$_4$  in the conventional cell
-xtal    = Crystal(cif_path ;symprec=1e-4)
+xtal    = Crystal(cif_path; symprec=1e-4)
 magxtal = subcrystal(xtal,"Co1")
 view_crystal(magxtal,6.0)
 print_symmetry_table(magxtal, 4.0)
@@ -214,7 +214,7 @@ symQpts   = [[0.75, 0.75, 0.00],  # List of wave vectors that define a path
             [0.25, 1.00, 0.25],
             [0.00, 1.00, 0.00],
             [0.00,-4.00, 0.00]];
-(Qpts, symQind) = connected_path(sc, symQpts,densQpts);
+(Qpts, xticks) = connected_path_from_rlu(magxtal, symQpts, densQpts);
 @time  iqw = intensities(sc, Qpts, :perp; interpolation = :none, kT=integrator.kT, formfactors=ffs); 
 
 # If desired, broaden the sc in energy
@@ -227,10 +227,10 @@ iqwc  = broaden_energy(sc, iqw, (ω, ω₀) -> lorentzian(ω-ω₀, η));
 # Plot the resulting I(Q,W)    
 heatmap(1:size(iqwc, 1), ωs(sc), iqwc;
     colorrange = (0, maximum(iqwc)/20000.0),
-    axis = (
+    axis = (;
         xlabel="Momentum Transfer (r.l.u)",
         ylabel="Energy Transfer (meV)", 
-        xticks = (symQind, string.(symQpts)),
+        xticks,
         xticklabelrotation=π/5,
         aspect = 1.4,
     )

examples/longer_examples/MgCr2O4-tutorial.jl

@@ -288,7 +288,7 @@ axsqw = (xticks=-4:4, yticks=0:2:10, ylabel="E (meV)", ylabelsize=18, xlabelsize
 
 qbs = 0.0:0.5:1.5 # Determine q_b for each slice
 for (i, qb) in enumerate(qbs)
-    path, labels = connected_path(sc_pyro, [[-4.0, qb, 0.0],[4.0, qb, 0.0]], 40)  # Generate a path of wave
+    path, _ = connected_path_from_rlu(xtal_pyro, [[-4.0, qb, 0.0],[4.0, qb, 0.0]], 40)  # Generate a path of wave
                                                                          ## vectors through the BZ
     Sqω_pyro  = intensities(sc_pyro, path, :perp; kT)  # Temperature keyword enables intensity rescaling
 
@@ -303,7 +303,7 @@ fig = Figure(; resolution=(1200,900))
 
 qbs = 0.0:0.5:1.5
 for (i, qb) in enumerate(qbs)
-    path, labels = connected_path(sc_mgcro, [[-4.0, qb, 0.0],[4.0, qb, 0.0]], 40)  # Generate a path of wave
+    path, _ = connected_path_from_rlu(xtal_mgcro, [[-4.0, qb, 0.0],[4.0, qb, 0.0]], 40)  # Generate a path of wave
                                                                          ## vectors through the BZ
     Sqω_mgcro  = intensities(sc_mgcro, path, :perp; kT)  # Temperature keyword enables intensity rescaling
 

examples/powder_averaging.jl

@@ -49,7 +49,7 @@ add_sample!(sc, sys)
 # lorentzian(ω-ω₀, 0.1)`. 
 
 qpoints = [[0.0, 0.0, 0.0], [0.5, 0.0, 0.0], [0.5, 0.5, 0.0], [0.0, 0.0, 0.0]]
-qs, markers = connected_path(sc, qpoints, 50) 
+qs, markers = connected_path_from_rlu(crystal, qpoints, 50)
 
 is = intensities_interpolated(sc, qs; interpolation=:round, formula = intensity_formula(sc,:trace))
 is_broad = broaden_energy(sc, is, (ω, ω₀) -> lorentzian(ω-ω₀, 0.1))

src/Intensities/Interpolation.jl

@@ -218,18 +218,24 @@ end
 
 
 """
-    connected_path(qs, density)
-
-Returns two things: First, a list of wavevectors that linearly interpolates
-between the points `qs` and second, a list of markers that index the locations
-of each original interpolation point.
-
-More sample-points will be returned between `q`-values that are further apart,
-and this is controlled by the `density` parameter.
+    connected_path_from_rlu(cryst, qs_rlu, density)
+
+Returns a pair `(path, xticks)`. The first return value is a path in reciprocal
+space that samples linearly between the wavevectors in `qs`. The elements in
+`qs` are defined in reciprocal lattice units (RLU) associated with the
+[`reciprocal_lattice_vectors``](@ref) for `cryst`. The `density` parameter has
+units of inverse length, and controls the number of samples between elements of
+`qs`.
+
+The second return value `xticks` can be used for plotting. The `xticks` object
+is itself a pair `(numbers, labels)`, which give the locations of the
+interpolating ``q``-points and a human-readable string.
 """
-function connected_path(qs::Vector, density)
-    @assert length(qs) >= 2 "The list `qs` should include at least two wavevectors."
-    qs = Vec3.(qs)
+function connected_path_from_rlu(cryst::Crystal, qs_rlu::Vector, density)
+    @assert length(qs_rlu) >= 2 "The list `qs` should include at least two wavevectors."
+    qs_rlu = Vec3.(qs_rlu)
+
+    qs = Ref(cryst.recipvecs) .* qs_rlu
 
     path = Vec3[]
     markers = Int[]
@@ -245,5 +251,10 @@ function connected_path(qs::Vector, density)
     push!(markers, length(path)+1)
     push!(path, qs[end])
 
-    return (path, markers)
+    labels = map(qs_rlu) do q_rlu
+        "[" * join(number_to_math_string.(q_rlu), ",") * "]"
+    end
+    xticks = (markers, labels)
+
+    return (path, xticks)
 end

src/SpinWaveTheory/SWTCalculations.jl

@@ -571,9 +571,7 @@ function intensity_formula(f::Function, swt::SpinWaveTheory, corr_ix; kernel::Un
     #
     #   Smooth kernel --> I_of_ω = Intensity as a function of ω
     #
-    calc_intensity = function(swt::SpinWaveTheory,q::Vec3)
-        _, qmag = chemical_to_magnetic(swt, q)
-
+    calc_intensity = function(swt::SpinWaveTheory, q::Vec3)
         if sys.mode == :SUN
             swt_hamiltonian_SUN!(swt, q, Hmat)
         elseif sys.mode == :dipole

src/Sunny.jl

@@ -49,9 +49,8 @@ include("Symmetry/AllowedCouplings.jl")
 include("Symmetry/AllowedAnisotropy.jl")
 include("Symmetry/Parsing.jl")
 include("Symmetry/Printing.jl")
-export Crystal, subcrystal, lattice_vectors, lattice_params, Bond,
-    reference_bonds, print_site, print_bond, print_symmetry_table,
-    print_suggested_frame
+export Crystal, subcrystal, lattice_vectors, lattice_params, reciprocal_lattice_vectors, Bond,
+    reference_bonds, print_site, print_bond, print_symmetry_table, print_suggested_frame
 
 include("Units.jl")
 export meV_per_K, Units
@@ -98,7 +97,7 @@ export SampledCorrelations, dynamical_correlations, instant_correlations, FormFa
 include("Intensities/ElementContraction.jl")
 
 include("Intensities/Interpolation.jl")
-export intensities_interpolated, instant_intensities_interpolated, connected_path
+export intensities_interpolated, instant_intensities_interpolated, connected_path_from_rlu
 
 include("Intensities/Binning.jl")
 export intensities_binned, BinningParameters, count_bins, integrate_axes!,

src/Symmetry/Crystal.jl

@@ -81,20 +81,6 @@ struct Crystal
     symprec        :: Float64                              # Tolerance to imperfections in symmetry
 end
 
-"""
-    natoms(cryst::Crystal)
-
-Number of atoms in the unit cell, i.e., number of Bravais sublattices.
-"""
-@inline natoms(cryst::Crystal) = length(cryst.positions)
-
-"""
-    cell_volume(cryst::Crystal)
-
-Volume of the crystal unit cell.
-"""
-cell_volume(cryst::Crystal) = abs(det(cryst.latvecs))
-
 # Constructs a crystal from the complete list of atom positions `positions`,
 # representing fractions (between 0 and 1) of the lattice vectors `latvecs`.
 # All symmetry information is automatically inferred.
@@ -145,6 +131,30 @@ function print_crystal_warnings(latvecs, positions)
     end
 end
 
+"""
+    natoms(cryst::Crystal)
+
+Number of atoms in the unit cell, i.e., number of Bravais sublattices.
+"""
+@inline natoms(cryst::Crystal) = length(cryst.positions)
+
+"""
+    cell_volume(cryst::Crystal)
+
+Volume of the crystal unit cell.
+"""
+cell_volume(cryst::Crystal) = abs(det(cryst.latvecs))
+
+"""
+    reciprocal_lattice_vectors(cryst::Crystal)
+
+Returns a ``3×3`` matrix, with columns that define the reciprocal lattice
+vectors ``(𝐛₁,𝐛₂,𝐛₃)``. These are defined to satisfy ``𝐛ᵢ⋅𝐚ⱼ = 2πδᵢⱼ``,
+where ``(𝐚₁,𝐚₂,𝐚₃)`` are the lattice vectors for `cryst` in real-space.
+"""
+reciprocal_lattice_vectors(cryst::Crystal) = cryst.recipvecs
+
+
 function spacegroup_name(hall_number::Int)
     # String representation of space group
     sgt = Spglib.get_spacegroup_type(hall_number)
@@ -501,8 +511,8 @@ function subcrystal(cryst::Crystal, classes::Vararg{Int, N}) where N
         @info "Atoms have been renumbered in subcrystal."
     end
 
-    ret = Crystal(cryst.latvecs, cryst.prim_latvecs, new_positions, new_types, new_classes, new_sitesyms,
-                  cryst.symops, cryst.spacegroup, cryst.symprec)
+    ret = Crystal(cryst.latvecs, cryst.prim_latvecs, cryst.recipvecs, new_positions, new_types,
+                  new_classes, new_sitesyms, cryst.symops, cryst.spacegroup, cryst.symprec)
     return ret
 end