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Diffstat (limited to 'scipy/weave/examples/ramp.py')
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1 files changed, 137 insertions, 0 deletions
diff --git a/scipy/weave/examples/ramp.py b/scipy/weave/examples/ramp.py new file mode 100644 index 000000000..d96466f56 --- /dev/null +++ b/scipy/weave/examples/ramp.py @@ -0,0 +1,137 @@ +""" Comparison of several different ways of calculating a "ramp" + function. + + C:\home\ej\wrk\junk\scipy\weave\examples>python ramp.py + python (seconds*ratio): 128.149998188 + arr[500]: 0.0500050005001 + compiled numeric1 (seconds, speed up): 1.42199993134 90.1195530071 + arr[500]: 0.0500050005001 + compiled numeric2 (seconds, speed up): 0.950999975204 134.752893301 + arr[500]: 0.0500050005001 + compiled list1 (seconds, speed up): 53.100001812 2.41337088164 + arr[500]: 0.0500050005001 + compiled list4 (seconds, speed up): 30.5500030518 4.19476220578 + arr[500]: 0.0500050005001 + +""" + +import time +import weave +from scipy_base.numerix import * + +def Ramp(result, size, start, end): + step = (end-start)/(size-1) + for i in xrange(size): + result[i] = start + step*i + +def Ramp_numeric1(result,start,end): + code = """ + const int size = Nresult[0]; + const double step = (end-start)/(size-1); + double val = start; + for (int i = 0; i < size; i++) + *result++ = start + step*i; + """ + weave.inline(code,['result','start','end'],compiler='gcc') + +def Ramp_numeric2(result,start,end): + code = """ + const int size = Nresult[0]; + double step = (end-start)/(size-1); + double val = start; + for (int i = 0; i < size; i++) + { + result[i] = val; + val += step; + } + """ + weave.inline(code,['result','start','end'],compiler='gcc') + +def Ramp_list1(result, start, end): + code = """ + const int size = result.len(); + const double step = (end-start)/(size-1); + for (int i = 0; i < size; i++) + result[i] = start + step*i; + """ + weave.inline(code, ["result","start", "end"], verbose=2) + +def Ramp_list2(result, start, end): + code = """ + const int size = result.len(); + const double step = (end-start)/(size-1); + for (int i = 0; i < size; i++) + { + PyObject* val = PyFloat_FromDouble( start + step*i ); + PySequence_SetItem(py_result,i, val); + } + """ + weave.inline(code, ["result", "start", "end"], verbose=2) + +def main(): + N_array = 10000 + N_py = 200 + N_c = 10000 + + ratio = float(N_c) / N_py + + arr = [0]*N_array + t1 = time.time() + for i in xrange(N_py): + Ramp(arr, N_array, 0.0, 1.0) + t2 = time.time() + py_time = (t2 - t1) * ratio + print 'python (seconds*ratio):', py_time + print 'arr[500]:', arr[500] + + arr1 = array([0]*N_array,Float64) + # First call compiles function or loads from cache. + # I'm not including this in the timing. + Ramp_numeric1(arr1, 0.0, 1.0) + t1 = time.time() + for i in xrange(N_c): + Ramp_numeric1(arr1, 0.0, 1.0) + t2 = time.time() + c_time = (t2 - t1) + print 'compiled numeric1 (seconds, speed up):', c_time, py_time/ c_time + print 'arr[500]:', arr1[500] + + arr2 = array([0]*N_array,Float64) + # First call compiles function or loads from cache. + # I'm not including this in the timing. + Ramp_numeric2(arr2, 0.0, 1.0) + t1 = time.time() + for i in xrange(N_c): + Ramp_numeric2(arr2, 0.0, 1.0) + t2 = time.time() + c_time = (t2 - t1) + print 'compiled numeric2 (seconds, speed up):', c_time, py_time/ c_time + print 'arr[500]:', arr2[500] + + arr3 = [0]*N_array + # First call compiles function or loads from cache. + # I'm not including this in the timing. + Ramp_list1(arr3, 0.0, 1.0) + t1 = time.time() + for i in xrange(N_py): + Ramp_list1(arr3, 0.0, 1.0) + t2 = time.time() + c_time = (t2 - t1) * ratio + print 'compiled list1 (seconds, speed up):', c_time, py_time/ c_time + print 'arr[500]:', arr3[500] + + arr4 = [0]*N_array + # First call compiles function or loads from cache. + # I'm not including this in the timing. + Ramp_list2(arr4, 0.0, 1.0) + t1 = time.time() + for i in xrange(N_py): + Ramp_list2(arr4, 0.0, 1.0) + t2 = time.time() + c_time = (t2 - t1) * ratio + print 'compiled list4 (seconds, speed up):', c_time, py_time/ c_time + print 'arr[500]:', arr4[500] + + +if __name__ == '__main__': + main()
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