"""
===============================
3D stack-of-spirals spin echo
===============================

A slab-selective excitation and 180-degree refocusing pulse form one spin echo,
followed by a spiral interleaf with Cartesian partition encoding. Spoilers
suppress unwanted coherence between repetitions. TE controls T2 weighting;
off-resonance affects the spiral readout. This sequence supports rapid 3D
T2-weighted imaging.
"""

# sphinx_gallery_start_ignore
import matplotlib

matplotlib.use("Agg")
import matplotlib.pyplot as plt

plt.rcParams.update(
    {
        "figure.dpi": 110,
        "savefig.dpi": 110,
        "font.size": 10,
        "axes.titlesize": 11,
        "axes.labelsize": 10,
    }
)


# sphinx_gallery_end_ignore

# %%
# Sixteen interleaves
# -------------------
#
# Sixteen interleaves at every partition.

import pypulseqpp as pp
from pypulseqpp.sequences import se_stack_of_spirals3D_sequence

baseline = se_stack_of_spirals3D_sequence(
    n=96, n_z=8, n_shots=16, te=None, tr=None, n_dummy=0
)
print(f"{baseline.num_blocks} blocks, {baseline.duration()[0]:.2f} s")


# %%
# Sequence diagram
# ----------------

baseline.paper_plot()

# %%
# Sampling order
# --------------
#
# The interleaves of every partition, over the three k-space axes.

pp.plot.plot_kspace(baseline, color_by="shot")

# %%
# Fewer interleaves
# -----------------
#
# Halving the interleaf count doubles the pitch and undersamples the
# peripheral k-space disc.

alternative = se_stack_of_spirals3D_sequence(
    n=96, n_z=8, n_shots=8, te=None, tr=None, n_dummy=0
)

# sphinx_gallery_start_ignore
print(f"{'':16} {'blocks':>8} {'duration (s)':>13} {'acquisitions':>13}")
for name, seq in (("16 interleaves", baseline), ("8 interleaves", alternative)):
    print(
        f"{name:16} {seq.num_blocks:8d} {seq.duration()[0]:13.2f} "
        f"{seq._native.num_adc():13d}"
    )
# sphinx_gallery_end_ignore

# %%
pp.plot.plot_kspace(alternative, color_by="shot")

# %%