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

A slab-selective spoiled excitation is followed by one spiral interleaf with
Cartesian partition encoding. Gradient and RF spoiling suppress residual
transverse coherence between repetitions. TR, flip angle, and TE determine
contrast. Stack-of-spirals SPGR supports rapid 3D structural and dynamic
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 gre_stack_of_spirals3D_sequence

baseline = gre_stack_of_spirals3D_sequence(n=96, n_z=8, n_shots=16, 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 halves the number of repetitions and doubles
# the spiral pitch. The resulting peripheral sampling is below the Nyquist rate.

alternative = gre_stack_of_spirals3D_sequence(
    n=96, n_z=8, n_shots=8, 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")

# %%