def __init__(self, f, xlist):

self.f = f

self.xlist = xlist

def run(self, methodname: str, fname: str, args: dict):

# path

X1_path = np.hstack(self.xlist)[0]

X2_path = np.hstack(self.xlist)[1]

Y_path = [self.f((x1, x2)) for x1, x2 in zip(X1_path, X2_path)]

totalstep = len(Y_path) - 1

X1absmax = max(abs(X1_path.min()), abs(X1_path.max()))

X2absmax = max(abs(X2_path.min()), abs(X2_path.max()))

X1 = np.linspace(-X1absmax, X1absmax, 100)

X2 = np.linspace(-X2absmax, X2absmax, 100)

# convex obj function landscape

X1_2d, X2_2d = np.meshgrid(X1, X2)

Y_2d = np.array([self.f((x1, x2)) for x2 in X2 for x1 in X1])

fig, ax = plt.subplots(figsize=(10, 5), subplot_kw={"projection":"3d"})

fig.set_size_inches(5, 5, True)

fontlabel = {"fontsize":"large", "color":"black", "fontweight":"bold"}

ax.set_xlabel("x1", fontdict=fontlabel, labelpad=16)

ax.set_ylabel('x2', fontdict=fontlabel, labelpad=16)

ax.set_title(f"{fname}\n\n{methodname} took {totalstep} steps", fontdict=fontlabel)

ax.view_init(elev=30., azim=120)

# scatter landscape

# cmap = 'inferno'

ax.scatter(X1_2d, X2_2d, Y_2d, c=Y_2d, cmap="cool", s=5, alpha=0.1)

# scatter path

ax.scatter(X1_path, X2_path, Y_path, c='red', s=8, alpha=1.)

def animate(i):

ax.view_init(elev=10., azim=i)

return fig,

anim = animation.FuncAnimation(fig, animate, frames=275, interval=20, blit=True)

filename = f"results/{methodname}_{fname.replace(' ', '_')}_stepsize{args.stepsize}_init{args.init}.gif"

print(f'Visualizing the trajectory at {filename} ...')