Groups
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Kian Lee Teo
Enable AHCI
The Advanced Host Controller Interface (AHCI) is a paramount feature for ensuring that Windows will support all of the features that come with running an SSD on your computer, especially the TRIM feature, which allows Windows to help the SSD perform its routine garbage collection. The term “garbage collection” is used to describe the phenomenon that occurs when a drive gets rid of information that is no longer considered to be in use.
To enable AHCI, you’ll have to enter the BIOS of your computer and enable it somewhere within its settings.
Enable TRIM
TRIM is vital to extending the lifespan of your SSD, namely by keeping it clean under the hood. Windows 10 should enable this by default, but it’s worth double-checking that it has been enabled.
To make sure TRIM is enabled, open your command prompt and enter the following:
fsutil behavior set disabledeletenotify 0
Disable Indexing
A good part of your SSD speed is consumed in indexing files for Windows search. This could be useful if you store everything you have on your SSD, but you might be annoyed by it if you experience slow-downs due to the periodic indexing process that occurs every time you add new data to the drive.
https://www.maketecheasier.com/12-things-you-must-do-when-running-a-solid-state-drive-in-windows-7/
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Kian Lee Teo
Firefox
To disable the crash recovery feature, set browser.sessionstore.resume_from_crash to false:
* Type about:config in the Location Bar * Press Enter * Find browser.sessionstore.resume_from_crash * Double click to set it to false
To completely disable all session saving behavior, including the recording of session information, set browser.sessionstore.enabled to false:
* Type about:config in the Location Bar * Press Enter * Find browser.sessionstore.enabled * Double click to set it to false
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Kian Lee Teo
Inline Functions
The inline functions are a C++ enhancement feature to decrease the execution time (lower latency) of a program. Functions can be instructed to compiler to make them inline so that compiler can replace those function definition wherever those are being called. Compiler replaces the definition of inline functions at compile time instead of referring function definition at runtime.
Pros
- It
speeds up
your program by avoiding function calling overhead. - It
save overhead of variables push/pop on the stack
, when function calling happens. - It
save overhead of return call
from a function. - It increases locality of reference by utilizing instruction cache.
- By marking it as inline, you can put a function definition in a header file (i.e. it can be included in multiple compilation unit, without the linker complaining)
Cons
- It increases the executable size due to code expansion.
- C++ inlining is resolved at compile time. Which means if you change the code of the inlined function, you would need to recompile all the code using it to make sure it will be updated
- When used in a header, it makes your header file larger with information which users don’t care.
- As mentioned above it increases the executable size, which
may cause thrashing in memory
. More number of page fault bringing down your program performance. - Sometimes not useful for example in
embedded system
where large executable size is not preferred at all due tomemory constraints
.
When to use
Function can be made as inline as per programmer need. Some useful recommendation are mentioned below-
- Use inline function when
performance is needed
. - Use inline function over macros.
- Prefer to use inline keyword outside the class with the function definition to hide implementation details.
- It
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Kian Lee Teo
Difference between Implied Volatility &. Historical Volatility
- Implied or projected volatility is a
forward-looking
metric used by options traders to calculate probability. - Implied volatility, as its name suggests, uses
supply and demand
, and represents the expected fluctuations of an underlying stock or index over a specific time frame. - With historical volatility, traders use
past trading ranges
of underlying securities and indexes to calculate price changes. - Calculations for historical volatility are generally based on the
change from one closing price
to the next.
- Implied or projected volatility is a
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Kian Lee Teo
Implied Volatility
Implied volatility is the parameter component of an option pricing model.
Not directly observable, so it needs to be solved using the five other inputs of the model:
- the market price of the option
- the underlying stock price
- the strike price
- the time to expiration
- the risk-free interest rate
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Kian Lee Teo
Historical Volatility
https://www.investopedia.com/terms/h/historicalvolatility.asp
Historical volatility (HV) is a statisticalmeasure of the dispersion of returns
for a given security or market index over a given period of time. This measure is calculated by determining theaverage deviation
from theaverage price
of a financial instrument in the given time period. Using standard deviation to calculate historical volatility. The higher the historical volatility value, the riskier the security.https://www.fool.com/knowledge-center/how-to-calculate-annualized-volatility.aspx
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Kian Lee Teo
1. Install Cygwin (https://cygwin.com/install.html)
2. Install Required Cygwin Packages
C:\cygwin64>setup-x86_64.exe -q -P wget -P gcc-g++ -P make -P diffutils -P libmpfr-devel -P libgmp-devel -P libmpc-devel
3. Download, Build and Install the Latest GCC
Open a Cygwin terminal
wget http://ftpmirror.gnu.org/gcc/gcc-9.1.0/gcc-9.1.0.tar.gz tar xf gcc-9.1.0.tar.gz
That will create a subdirectory named gcc-4.9.2. Next, we’ll configure our GCC build.
mkdir build-gcc cd build-gcc ../gcc-9.1.0/configure --program-suffix=-9.1.0 --enable-languages=c,c++ --disable-bootstrap --disable-shared
Next, we’ll actually build the new GCC compiler suite, including C, C++ and the standard C++ library. This is the longest step.
make -j4
The -j4 option lets the build process spawn up to four child processes in parallel.
Once that’s finished, install the new compiler:
make install cd ..
https://preshing.com/20141108/how-to-install-the-latest-gcc-on-windows/
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Kian Lee Teo
The Google Edge TPU coprocessor has support for TensorFlow Lite, or ‘machine learning at the edge’. The point of TensorFlow Lite isn’t to train a system, but to run an existing model.
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