Comment 3 for bug 785244

New and improved with comments explaining:

from dolfin import *
mesh = UnitSquare(30,30)
V = FunctionSpace(mesh, "CG", 1)
x = triangle.x

# Compute f(x,y) = x on Omega = [0,1]^2
f = project(x[0], V)

# Assert that max f = max x on Omega = 1
fmax = f.vector().max()
print fmax # Prints 0.67, not 1.0
assert abs(fmax - 1.0) < 1e-8 # should pass, fails

On 19 May 2011 18:21, Martin Sandve Alnæs <email address hidden> wrote:
> Written on the bus and untested:
>
> mesh = UnitSquare(30,30)
>
> V = FunctionSpace(mesh, "CG", 1)
> y = project(triangle.x[0], V)
> print y.vector().max() # should be 1.0, is 0.67
>
> Martin
>
> Den 19. mai 2011 18.10 skrev "Garth Wells" <email address hidden>
> følgende:
>> This test is a bit cryptic. Can you make it easy for us and explain what
>> the expected result is (and how to check it), and what the actual result
>> is (and how to check it).
>>
>> --
>> You received this bug notification because you are a direct subscriber
>> of the bug.
>> https://bugs.launchpad.net/bugs/785244
>>
>> Title:
>> Spatial coordinates in form are scaled by 2/3 in 2D
>>
>> Status in DOLFIN:
>> New
>>
>> Bug description:
>> Here's a program that plots y=x, y=2x, y=3x in 1D and 2D, giving
>> correct plots in 1D but scaled by 2/3 in 2D:
>>
>>
>> from dolfin import *
>>
>> n = 30
>> factor = 1.0
>>
>> #cell = interval
>> cell = triangle
>>
>> d = cell.d
>> if d == 1:
>> mesh = UnitInterval(n)
>> elif d == 2:
>> mesh = UnitSquare(n, n)
>> #factor = 3.0/2.0 # Enable this to adjust for bug and get correct plots
>>
>> # Asserting that x indeed goes from 0 to 1
>> assert mesh.coordinates()[:].max() == 1.0
>> assert mesh.coordinates()[:].min() == 0.0
>>
>> # Hack for bug in ffc, fix proposed for merging into dev branch
>> x = cell.x if d == 1 else cell.x[0]
>>
>> V = FunctionSpace(mesh, "CG", 1)
>>
>> for k in range(1, 4):
>> u = factor*k*x
>> print str(u)
>> uh = project(u, V)
>> plot(uh, vmin=-1.0, vmax=1.0)
>>
>> interactive()
>>
>> To unsubscribe from this bug, go to:
>> https://bugs.launchpad.net/dolfin/+bug/785244/+subscribe
>