From a31143a635848914a26b6de28b4b6d33419fdc60 Mon Sep 17 00:00:00 2001
From: Michiel Cottaar <MichielCottaar@protonmail.com>
Date: Fri, 31 May 2024 12:01:10 +0100
Subject: [PATCH] Allow BuildingBlock to start/end with non-zero gradient
This is to support Pulseq, where this behaviour is allowed.
---
src/containers/building_blocks.jl | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/src/containers/building_blocks.jl b/src/containers/building_blocks.jl
index 0f9c07f..c9dea4f 100644
--- a/src/containers/building_blocks.jl
+++ b/src/containers/building_blocks.jl
@@ -92,10 +92,18 @@ The gradient is linearly interpolated between these points (see [`waveform_seque
"""
function waveform(bb::BaseBuildingBlock)
ndim = ndim_grad(bb)
+ first_block = waveform_sequence(bb)[1][2]
+ if first_block isa NoGradient
+ first_grad = ndim == 3 ? zero(SVector{3, Float64}) : 0.
+ elseif first_block isa ConstantGradient
+ first_grad = first_block.gradient_strength
+ else
+ first_grad = first_block.gradient_strength_start
+ end
if ndim == 3
- result = Tuple{VariableType, SVector{3, VariableType}}[(0., zero(SVector{3, Float64}))]
+ result = Tuple{VariableType, SVector{3, VariableType}}[(0., first_grad)]
elseif ndim == 1
- result = Tuple{VariableType, VariableType}[(0., 0.)]
+ result = Tuple{VariableType, VariableType}[(0., first_grad)]
else
return []
end
@@ -116,7 +124,6 @@ function waveform(bb::BaseBuildingBlock)
error("Unrecognised block type in BuildingBlock: $(typeof(bb)).")
end
end
- @assert all(abs.(result[end][2]) .<= 1e-12) "$(typeof(bb)) does not end up with a gradient of zero. This is probably caused by an improper implementation of this BuildingBlock."
return result
end
--
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