def map_forward(self, p):
from mitsuba.core import Vector3f
cos_theta = -p.y
sin_theta = ek.safe_sqrt(ek.fnmadd(cos_theta, cos_theta, 1))
sin_phi, cos_phi = ek.sincos(p.x)
return Vector3f(cos_phi * sin_theta, sin_phi * sin_theta, cos_theta)
def test40_safe_functions(m):
x = ek.linspace(m.Float, 0, 1, 10)
y = ek.linspace(m.Float, -1, 1, 10)
z = ek.linspace(m.Float, -1, 1, 10)
ek.enable_grad(x, y, z)
x2 = ek.safe_sqrt(x)
y2 = ek.safe_acos(y)
z2 = ek.safe_asin(z)
ek.backward(x2)
ek.backward(y2)
ek.backward(z2)
assert ek.grad(x)[0] == 0
assert ek.allclose(ek.grad(x)[1], .5 / ek.sqrt(1 / 9))
assert x[0] == 0
assert ek.all(ek.isfinite(ek.grad(x)))
assert ek.all(ek.isfinite(ek.grad(y)))
assert ek.all(ek.isfinite(ek.grad(z)))