registerGradEvent¶

Pre-registers a gradient event in the sequence object's library for performance optimization. This method stores gradient events (trapezoids or arbitrary gradients) in an internal library and returns a unique ID that can be used for fast event retrieval in loops. This significantly accelerates sequence assembly when the same gradient event is used multiple times.

Syntax¶

function [id, shapeIDs] = registerGradEvent(event)

Calling Pattern¶

[id, shapeIDs] = seq.registerGradEvent(gradientEvent)

Parameters¶

Required Parameters¶

Name	Type	Default	Description	Example
`event`	struct		A gradient event structure created by makeTrapezoid, makeArbitraryGrad, or scaleGrad	`makeTrapezoid('x', 'Area', 1e-4)`

Returns¶

Output	Type	Description
`id`	double	Unique identifier for the registered gradient event in the library
`shapeIDs`	array	Array of shape IDs for gradient waveform components (optional output)

Usage Notes¶

Pre-registering gradient events is particularly useful in loops where the same gradient is used repeatedly
The returned ID can be stored in the event structure as event.id for faster addBlock operations
This method automatically handles gradient shape compression for efficient storage
Supports both trapezoidal and arbitrary gradient waveforms

Examples¶

% From MPRAGE sequence: pre-register objects that do not change while looping
gslSp.id = seq.registerGradEvent(gslSp);
groSp.id = seq.registerGradEvent(groSp);
gro1.id = seq.registerGradEvent(gro1);

% Pre-register phase-encoding gradients that repeat in the inner loop
gpe2je = mr.scaleGrad(gpe2, pe2Steps(PEsamp(count)));
gpe2je.id = seq.registerGradEvent(gpe2je);
gpe2jr = mr.scaleGrad(gpe2, -pe2Steps(PEsamp(count)));
gpe2jr.id = seq.registerGradEvent(gpe2jr);

% Use pre-registered gradients in sequence assembly
for i = 1:N(ax.n2)  % inner loop for partition encoding
    if (i == 1)
        seq.addBlock(rf);
    else
        seq.addBlock(rf, groSp, mr.scaleGrad(gpe1, -pe1Steps(i-1)), gpe2jr);
    end
    seq.addBlock(adc, gro1, mr.scaleGrad(gpe1, pe1Steps(i)), gpe2je);
end