Gradient design

Gradient events on one logical gradient axis, and the operations on them. Amplitudes are in Hz/m, slew rates in Hz/m/s, gradient areas in 1/m and times in s, except where a docstring states otherwise; Events and blocks describes the trapezoid and arbitrary gradient events.

Gradient factories

Object	Input	Returns	Purpose
make_arbitrary_grad	Channel, amplitudes at raster centres, endpoint amplitudes	Arbitrary gradient event	Sampled gradient waveform.
make_crusher	Dephasing cycles, voxel size (m), channel, endpoint amplitudes	Extended trapezoid; vertex times and amplitudes	Crusher of dephasing_cycles / voxel_size area.
make_extended_trapezoid	Channel, amplitude and time points	Extended trapezoid (arbitrary gradient event)	Piecewise-linear gradient waveform.
make_extended_trapezoid_area	Area, channel, endpoint amplitudes	Extended trapezoid; vertex times and amplitudes	Shortest extended trapezoid for an area.
make_hexagon_gradient_area	Channel, endpoint amplitudes, area	Gradient event; corner times and amplitudes	Minimum-duration gradient for an area.
make_phase_blip	Channel, FOV (m), steps, duration	Trapezoid of area steps / fov	Echo-train phase-encode blip.
make_phase_encoding	Channel, resolution (m), duration	Trapezoid of area 1 / (2 * resolution)	Largest phase encode, scaled per view.
make_trapezoid	Channel; area, flat area or amplitude; timing	Trapezoid event	Trapezoidal gradient.
make_wave_gradients	Flat time, cycles, amplitude (T/m), channels	Sine and cosine arbitrary gradients; optional amplitude (T/m)	Wave-CAIPI wave-encoding gradients.

Gradient operations

Each docstring states how the operation changes the event’s timing.

Object	Input	Returns	Purpose
add_gradients	Gradient events on one axis	Gradient event	Superposition.
calc_ramp	Two k-space point pairs (3, 2) (1/m), limits	Connecting k-space points; success flag	Minimum-time 3D k-space connection.
concatenate_gradients	Gradient events on one channel, in play order	One gradient event	Concatenation.
points_to_waveform	Amplitude and time points, gradient raster	Waveform on the gradient raster	Interpolation onto the raster.
rotate_3d	Rotation matrix, quaternion or angles; block events	Non-gradient events, then rotated gradients	3D rotation of a block’s gradients.
scale_grad	Gradient event, scale factor	Scaled gradient event	Amplitude scaling.
split_gradient	Trapezoid	Ramp-up, plateau and ramp-down events	Trapezoid decomposition.
split_gradient_at	Gradient event, time (s)	Two gradient events whose sum is the input	Split at a time point.