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What is in your Mathematica tool bag? [closed]
We all know that Mathematica is great, but it also often lacks critical functionality. What kind of external packages / tools / resources do you use with Mathematica?
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Best practices for circular shift (rotate) operations in C++
...,7 which is slower and takes more bytes than rol edi,7 on some CPUs (especially AMD, but also some Intel), when BMI2 isn't available for rorx eax,edi,25 to save a MOV.
MSVC: x86-64 CL19: Only recognized for constant-count rotates. (The wikipedia idiom is recognized, but the branch and AND aren't op...
How to achieve function overloading in C?
...sociation list that looks a bit like a switch block. _Generic gets the overall type of the expression and then "switches" on it to select the end result expression in the list for its type:
_Generic(1, float: 2.0,
char *: "2",
int: 2,
default: get_two_object());
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__lt__ instead of __cmp__
...ttributes of the new class it's decorating (the result might be microscopically faster at runtime, at equally minute cost in terms of memory).
Of course, if your class has some particularly fast way to implement (e.g.) __eq__ and __ne__, it should define them directly so the mixin's versions are no...
Python (and Python C API): __new__ versus __init__
...vs immutable types.
__new__ accepts a type as the first argument, and (usually) returns a new instance of that type. Thus it is suitable for use with both mutable and immutable types.
__init__ accepts an instance as the first argument and modifies the attributes of that instance. This is inappropr...
Remove duplicate elements from array in Ruby
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array = array.uniq
uniq removes all duplicate elements and retains all unique elements in the array.
This is one of many beauties of the Ruby language.
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How to access the ith column of a NumPy multidimensional array?
...nswered Apr 20 '13 at 14:05
AkavallAkavall
62.1k3838 gold badges170170 silver badges215215 bronze badges
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How do I achieve the theoretical maximum of 4 FLOPs per cycle?
... while (i < 1000){
// Here's the meat - the part that really matters.
r0 = _mm_mul_pd(r0,rC);
r1 = _mm_add_pd(r1,rD);
r2 = _mm_mul_pd(r2,rE);
r3 = _mm_sub_pd(r3,rF);
r4 = _mm_mul_pd(r4,rC);
r5 = _mm_add_pd(r5...
Get a filtered list of files in a directory
...t a list of files in a directory using Python, but I do not want a list of ALL the files.
14 Answers
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Is there a performance difference between a for loop and a for-each loop?
... iterator or index variable
completely. The resulting idiom
applies equally to collections and
arrays:
// The preferred idiom for iterating over collections and arrays
for (Element e : elements) {
doSomething(e);
}
When you see the colon (:), read it as
“in.” Thus, the loop ab...