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Questions tagged [underflow]

An arithmetic underflow is a condition in a computer program where the result of a calculation is a number of smaller absolute value than the computer can actually represent in memory.

In computing, buffer underrun or buffer underflow is a state occurring when a buffer used to communicate between two devices or processes is fed with data at a lower speed than the data is being read from it. This requires the program or device reading from the buffer to pause its processing while the buffer refills.

From Wikipedia

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Calculating log-sum-exp function in c++

Are there any functions in the c++ standard library that calculate the log of the sum of exponentials? If not, how should I go about writing my own? Do you have any suggestions not mentioned in this wiki article? I am concerned specifically with the…
Taylor
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C# ulong overflow / underflow somehow allowed

I'm a little confused about the behavior of the ulong type. I understand it to be a 64-bit integer used for positive numbers (max value 18,446,744,073,709,551,615). I just started using it because I need really big positive numbers, but there's some…
SleekPanther
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Qt QAudioOutput buffer underflow when playing from file

I have implemented a simple Qt program based on the example in the QAudioOutput documentation here. The program plays raw audio from a file using QAudioOutput when I press a button. The audio plays fine but I receive Got a buffer underflow! at the…
Pobbel
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Understanding signed vs unsigned comparison

Can somebody tell me why the if condition is false? #include using namespace std; int main(int argc, char *argv[]) { int a; unsigned int ua; a = -1; ua = a; cout << "ua: " << ua << endl; if (ua != -1) …
harryPoker
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Canvas restore() causing underflow exception in very rare cases

Through ACRA, I have received a small number of reports from an alpha build of software that show that an exception is occurring during a specific call to Canvas.restore(). The exception is java.lang.IllegalStateException: Underflow in restore. I am…
Trevor
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How to handle floating-point underflow?

I'm trying to understand C++ numerical properties. Thus, I am interested by the underflow phenomenon. Can anyone give me an example of an underflow and how to handle it?
WildThing
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How can an underflow lead to an overflow?

I'm reading the Intel Manual (Intel® 64 and IA-32 Architectures Software Developer Manuals *2016) and am curious if I understand this one excerpt correctly about the need for an Underflow Exception: The ability to detect and handle underflow is…
Robert Houghton
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Avoid underflow using exp and minimum positive float128 in numpy

I am trying to calculate the following ratio: w(i) / (sum(w(j)) where w are updated using an exponential decreasing function, i.e. w(i) = w(i) * exp(-k), k being a positive parameter. All the numbers are non-negative. This ratio is then used to a…
user90772
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Underflow in Forward Algorithm for HMMs

I'm implementing the forward algorithm for HMMs to calculate the probability of a given HMM emitting a given observation sequence. I'd like my algorithm to be robust to underflow. I can't work in log-space because the forward algorithm requires…
akobre01
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Forms of constants for high performance addition and multiplication for double

I need to efficiently add or multiply some constants to a result of type double in a loop to prevent underflow. For example, if we have int, multiplying with a power of 2 will be fast as the compiler will use bit shift. Is there a form of constants…
ggg
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Underflow error in floating point arithmetic in C

I am new to C, and my task is to create a function f(x) = sqrt[(x^2)+1]-1 that can handle very large numbers and very small numbers. I am submitting my script on an online interface that checks my answers. For very large numbers I simplify the…
lcleary
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Overflow and Underflow in Java Float and Double Data Types

I have created the following code to test Float and Double Java numeric data types for underflow and overflow: // Float Overflow & Underflow float floatTest = Float.MAX_VALUE; floatTest++; out.println("Float Overflow: " + Float.MAX_VALUE + " + 1 = "…
jjj
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Why does complex floating-point division underflow weirdly with NumPy?

Consider this code: import numpy numpy.seterr(under='warn') x1 = 1 + 1j / (1 << 533) x2 = 1 - 1j / (1 << 533) y1 = x1 * 1.1 y2 = x2 * 1.1 z1 = x1 / 1.1 z2 = x2 / 1.1 print(numpy.divide(1, x1)) # 1-3.55641399918e-161j #…
user541686
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How to avoid underflow when multiplying real numbers?

I would like to know if there is a proper way to multiply or square float (or double) numbers together without having underflow error when I compile my Fortran code like gfortran -ffpe-trap=invalid,zero,overflow,underflow ... I know that the…
R. N
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How can I prevent/detect an underflow in a Postgresql calculation that uses EXP()

I am receiving a value out of range: underflow error from pgsql, in a query that uses the EXP(x) function. What values of x trigger this? How do I prevent or detect it?
pc1oad1etter
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