re-order statements
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@ -59,6 +59,7 @@ Setup:
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## Back to the Python benchmark (third try)
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- can we explain what is happening now? Yes, more or less ;-)
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- quick fix for the [puzzle](puzzle.ipynb): try and add `order='F'` in the "bad" snippet and see that it "fixes" the bug ➔ why?
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- the default memeory layout is also called row-major `== C_CONTIGUOUS`
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- rule of thumb for multi-dimensional numpy arrays:
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- the right-most index should be the inner-most loop in a series of nested loops over the dimensions of a multi-dimensional array
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@ -70,10 +71,10 @@ Setup:
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```
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- … unless of course you plan to mostly loop *across* time series :)
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- watch out when migrating code from MATLAB® or to `pandas.DataFrame` ➔ they store data in memory using the opposite convention, the column-major order!!!
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- quick fix for the [puzzle](puzzle.ipynb): try and add `order='F'` in the "bad" snippet and see that is "fixes" the bug ➔ why?
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Notes on the [Python benchmark](benchmark_python/):
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- while running it attached to the P-core (`cpu0`), the P-core was running under a constant load of 100% (almost completely user-time) and at a fixed frequency of 3.8 GHz, where the theoretical max would be 5.2 GHz
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- while running it attached to one core on my laptop, the core was running under a constant load of 100% (almost completely user-time) and at a fixed frequency of 3.8 GHz, where the theoretical max would be 5.2 GHz
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➔ the CPU does not "starve" because it scales its speed down to match the memory throughput? Or I am misinterpreting this? This problem which at first sight should be perfectly memory-bound, becomes CPU-bound, or actually, exactly balanced? From the [Intel documentation](https://lenovopress.lenovo.com/lp1836-tuning-uefi-settings-4th-gen-intel-xeon-scalable-processor):
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> **Energy Efficient Turbo**
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