from math import gamma
from numpy import arange, array
import matplotlib as mp
import matplotlib.pyplot as plot

lw_grid = 1.6
lw_line = 2
axes_color = "#505050"

blue = [0,0.2,0.6,0.8]
green = [0,0.46,0,0.8]
magenta = [0.6,0,0.4,0.8]
black = [0,0,0,0.8]

style = {
  "axes.linewidth": lw_grid,
  "grid.linewidth": lw_grid,
  "grid.linestyle": "solid",
  "grid.color": "#e0e0d4",
  "lines.linewidth": 2,
  # "lines.markersize": 10,
  "xtick.labelsize": 14,
  "ytick.labelsize": 14,
}
mp.rcParams.update(style)

fig = plot.figure()
ax = fig.add_subplot(1,1,1)

ax.spines['bottom'].set_color(axes_color)
ax.spines['top'].set_color(axes_color) 
ax.spines['right'].set_color(axes_color)
ax.spines['left'].set_color(axes_color)
ax.spines['bottom'].set_zorder(10)
ax.spines['top'].set_zorder(10)
ax.spines['right'].set_zorder(10)
ax.spines['left'].set_zorder(10)

ax.spines['left'].set_position('zero')
ax.spines['bottom'].set_position('zero')
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

ax.xaxis.grid()
ax.yaxis.grid()
ax.set_axisbelow(True)
ax.xaxis.set_tick_params(width=lw_grid, length=10,
  pad=8,color=axes_color,direction='inout')
ax.yaxis.set_tick_params(width=lw_grid, length=10,
  pad=8,color=axes_color,direction='inout')
ax.set_aspect('equal')

X=[-6,6] 
Y=[-6,6]
ax.axis(X+Y)
ax.set_xticks(list(range(X[0],0,1))+list(range(1,X[1]+1,1)))
ax.set_yticks(list(range(Y[0],0,1))+list(range(1,X[1]+1,1)))

def f(x):
  try:
    return gamma(x)
  except:
    return float("nan")

x = arange(0, 10, 0.01)
y = array(map(f,x))
ax.plot(x,y, color=blue, zorder=3, linewidth=lw_line)
for k in range(-6,0):
  x = arange(k, k+1, 0.0001)
  y = array(map(f,x))
  ax.plot(x,y, color=blue, zorder=3, linewidth=lw_line)

plot.savefig("gamma.svg",bbox_inches='tight')
# plot.show()