Skip to content
Fetching contributors…
Cannot retrieve contributors at this time
63 lines (54 sloc) 1.51 KB
from sympy import *
def textplot(expr, a, b, W=55, H=18):
"""
Print a crude ASCII art plot of the SymPy expression 'expr' (which
should contain a single symbol, e.g. x or something else) over the
interval [a, b].
Example: textplot(sin(t)*t, 0, 15)
"""
f = None
for x in expr.atoms():
if isinstance(x, Symbol):
f = lambdify([x], expr)
break
assert f is not None
a = float(a)
b = float(b)
# Calculate function values
y = [0] * W
for x in range(W):
try:
y[x] = f(a+(b-a)/float(W)*x)
except TypeError:
y[x] = 0
# Normalize height to screen space
ma = max(y)
mi = min(y)
for x in range(W):
y[x] = int(float(H)*(y[x]-mi)/(ma-mi))
margin = 7
print
for h in range(H-1, -1, -1):
s = [' '] * W
for x in range(W):
if y[x] == h:
s[x] = '.'
# Print y values
if h == H-1:
prefix = ("%g" % ma).rjust(margin)[:margin]
elif h == H//2:
prefix = ("%g" % ((mi+ma)/2)).rjust(margin)[:margin]
elif h == 0:
prefix = ("%g" % mi).rjust(margin)[:margin]
else:
prefix = " "*margin
s = "".join(s)
if h == H//2:
s = s.replace(" ", "-")
print prefix + " | " + s
# Print x values
bottom = " " * (margin + 3)
bottom += ("%g" % a).ljust(W//2-4)
bottom += ("%g" % ((a+b)/2)).ljust(W//2)
bottom += "%g" % b
print bottom
Jump to Line
Something went wrong with that request. Please try again.