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Mandelbrot example: double precision #569

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19 changes: 10 additions & 9 deletions examples/demo_mandelbrot.py
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@ def calc_fractal_opencl(q, maxiter):
ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)

output = np.empty(q.shape, dtype=np.uint16)
output = np.empty(q.shape, dtype=np.uint32)

mf = cl.mem_flags
q_opencl = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=q)
Expand All @@ -48,12 +48,13 @@ def calc_fractal_opencl(q, maxiter):
ctx,
"""
#pragma OPENCL EXTENSION cl_khr_byte_addressable_store : enable
__kernel void mandelbrot(__global float2 *q,
__global ushort *output, ushort const maxiter)
#pragma OPENCL EXTENSION cl_khr_fp64 : enable
__kernel void mandelbrot(__global double2 *q,
__global uint *output, uint const maxiter)
{
int gid = get_global_id(0);
float nreal, real = 0;
float imag = 0;
double nreal, real = 0;
double imag = 0;

output[gid] = 0;

Expand All @@ -70,7 +71,7 @@ def calc_fractal_opencl(q, maxiter):
).build()

prg.mandelbrot(
queue, output.shape, None, q_opencl, output_opencl, np.uint16(maxiter)
queue, output.shape, None, q_opencl, output_opencl, np.uint32(maxiter)
)

cl.enqueue_copy(queue, output, output_opencl).wait()
Expand All @@ -82,7 +83,7 @@ def calc_fractal_serial(q, maxiter):
# calculate z using pure python on a numpy array
# note that, unlike the other two implementations,
# the number of iterations per point is NOT constant
z = np.zeros(q.shape, complex)
z = np.zeros(q.shape, np.complex128)
output = np.resize(
np.array(
0,
Expand All @@ -107,7 +108,7 @@ def calc_fractal_numpy(q, maxiter):
),
q.shape,
)
z = np.zeros(q.shape, np.complex64)
z = np.zeros(q.shape, np.complex128)

for it in range(maxiter):
z = z * z + q
Expand All @@ -129,7 +130,7 @@ def draw(self, x1, x2, y1, y2, maxiter=30):
# draw the Mandelbrot set, from numpy example
xx = np.arange(x1, x2, (x2 - x1) / w)
yy = np.arange(y2, y1, (y1 - y2) / h) * 1j
q = np.ravel(xx + yy[:, np.newaxis]).astype(np.complex64)
q = np.ravel(xx + yy[:, np.newaxis]).astype(np.complex128)

start_main = time.time()
output = calc_fractal(q, maxiter)
Expand Down