NoGradient should always be 0-dimensional

src/components/gradient_waveforms/gradient_waveforms.jl

@@ -2,17 +2,17 @@
 Module defining sub-types of the [`GradientWaveform`](@ref).
 
 There are only three types of [`GradientBlock`] objects:
-- [`ChangingGradientBlock`](@ref): any gradient changing linearly in strength.
-- [`ConstantGradientBlock`](@ref): any gradient staying constant in strength. These can overlap with a pulse (`SliceSelectPulse`).
-- [`NoGradientBlock`](@ref): any part of the gradient waveform when no gradient is active.
+- [`ChangingGradient`](@ref): any gradient changing linearly in strength.
+- [`ConstantGradient`](@ref): any gradient staying constant in strength. These can overlap with a pulse (`SliceSelectPulse`).
+- [`NoGradient`](@ref): any part of the gradient waveform when no gradient is active.
 
 These parts are combined into a full gradient waveform in a `BuildingBlock`.
 
 Each part of this gradient waveform can compute:
-- [`gradient_strength`]: maximum gradient strength in each dimension.
-- [`slew_rate`]: maximum slew rate in each dimension.
-- [`qvec`]: area under curve in each dimension
-- [`bmat_gradient`]: diffusion weighting (scalar in 1D or matrix in 3D).
+- `gradient_strength`: maximum gradient strength in each dimension.
+- `slew_rate`: maximum slew rate in each dimension.
+- `qval`/`qval3`: area under curve
+- `bmat_gradient`: diffusion weighting (scalar in 1D or matrix in 3D).
 """
 module GradientWaveforms
 

src/components/gradient_waveforms/no_gradient_blocks.jl

@@ -5,38 +5,26 @@ import ...AbstractTypes: GradientWaveform
 import ..ChangingGradientBlocks: split_gradient
 
 """
-    NoGradient{N}(duration)
+    NoGradient(duration)
 
 Part of a gradient waveform when there is no gradient active.
 
-`N` needs to be set to 1 if `orientation` is fixed in the gradient waveform or 3 otherwise.
-
 Usually, you do not want to create this object directly, use a `BuildingBlock` instead.
 """
-struct NoGradient{N} <: GradientWaveform{N}
+struct NoGradient <: GradientWaveform{0}
     duration :: VariableType
-    function NoGradient{N}(duration) where {N}
-        if !(N in (1, 3))
-            error("Dimensionality of the gradient should be 1 or 3, not $N")
-        end
-        new(duration)
-    end
 end
 
 duration(ngb::NoGradient) = ngb.duration
 for func in (:qval, :gradient_strength, :slew_rate)
-    @eval $func(::NoGradient{1}) = 0.
-    @eval $func(::NoGradient{3}) = zero(SVector{3, Float64})
+    @eval $func(::NoGradient) = 0.
 end
 
-gradient_strength(cgb::NoGradient, time::Number) = gradient_strength(cgb)
-
-NoGradient(duration) = NoGradient{1}(duration)
+gradient_strength(nb::NoGradient, time::Number) = 0.
 
-bmat_gradient(::NoGradient{1}) = 0.
-bmat_gradient(::NoGradient{3}) = zero(SMatrix{3, 3, Float64, 9})
-bmat_gradient(ngb::NoGradient{1}, qstart::VariableType) = qstart^2 * duration(ngb)
-bmat_gradient(ngb::NoGradient{3}, qstart::AbstractVector{<:VariableType}) = @. qstart * permutedims(qstart) * duration(ngb)
+bmat_gradient(::NoGradient) = 0.
+bmat_gradient(ngb::NoGradient, qstart::VariableType) = qstart^2 * duration(ngb)
+bmat_gradient(ngb::NoGradient, qstart::AbstractVector{<:VariableType}) = @. qstart * permutedims(qstart) * duration(ngb)
 
 function split_gradient(ngb::NoGradient, times::VariableType...)
     durations = [times[1], [t[2] - t[1] for t in zip(times[1:end-1], times[2:end])]..., duration(ngb) - times[end]]

src/containers/base_sequences.jl

@@ -173,7 +173,7 @@ Converst object into something that can be included in the sequence:
 to_block(cb::ContainerBlock) = cb
 to_block(s::Symbol) = to_block(Val(s))
 to_block(s::Union{VariableType, Nothing, Val{:min}, Val{:max}}) = Wait(s)
-to_block(ec::EventComponent) = BuildingBlock([NoGradient{3}(duration(ec)), (0., ec)])
+to_block(ec::EventComponent) = BuildingBlock([NoGradient(duration(ec)), (0., ec)])
 
 
 function make_generic(seq::BaseSequence)

src/containers/building_blocks.jl

@@ -274,7 +274,6 @@ end
 function BuildingBlock(waveform::AbstractVector, events::AbstractVector; orientation=nothing, group=nothing)
     events = Any[events...]
     waveform = Any[waveform...]
-    ndim = isnothing(orientation) ? 1 : 3
     zero_grad = isnothing(orientation) ? zeros(3) : 0.
     if length(waveform) == 0 || waveform[1][1] > 0.
         pushfirst!(waveform, (0., zero_grad))
@@ -284,7 +283,7 @@ function BuildingBlock(waveform::AbstractVector, events::AbstractVector; orienta
     for (index_grad, ((prev_time, prev_grad), (time, grad))) in enumerate(zip(waveform[1:end-1], waveform[2:end]))
         duration = time - prev_time
         if norm(prev_grad) <= 1e-12 && norm(grad) <= 1e-12
-            push!(components, NoGradient{ndim}(duration))
+            push!(components, NoGradient(duration))
         elseif norm(prev_grad) ≈ norm(grad)
             push!(components, ConstantGradient(prev_grad, orientation, duration, group))
         else
@@ -352,6 +351,6 @@ end
 
 duration(wb::Wait) = wb.duration
 Base.keys(::Wait) = (Val(:empty),)
-Base.getindex(wb::Wait, ::Val{:empty}) = NoGradient{1}(wb.duration)
+Base.getindex(wb::Wait, ::Val{:empty}) = NoGradient(wb.duration)
 
 end
\ No newline at end of file