floating-point

问题 As I understand it, Ruby (1.9.2) floats have a precision of 15 decimal digits. Therefore, I would expect rounding float x to 15 decimal places would equal x . For this calculation this isn't the case. x = (0.33 * 10) x == x.round(15) # => false Incidentally, rounding to 16 places returns true. Can you please explain this to me? 回答1: Part of the problem is that 0.33 does not have an exact representation in the underlying format, because it cannot be expressed by a series of 1 / 2 n terms. So,

问题 As I understand it, Ruby (1.9.2) floats have a precision of 15 decimal digits. Therefore, I would expect rounding float x to 15 decimal places would equal x . For this calculation this isn't the case. x = (0.33 * 10) x == x.round(15) # => false Incidentally, rounding to 16 places returns true. Can you please explain this to me? 回答1: Part of the problem is that 0.33 does not have an exact representation in the underlying format, because it cannot be expressed by a series of 1 / 2 n terms. So,

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问题 I am writing a marshaling layer to automatically convert values between different domains. When it comes to floating point values this potentially means converting values from one floating point format to another. However, it seems that almost every modern system is using IEEE754, so I'm wondering whether it's actually worth generalising to allow other formats, or just manage marshaling between different IEEE754 formats. Does anyone know of any commonly used floating point formats other than

问题 I am writing a marshaling layer to automatically convert values between different domains. When it comes to floating point values this potentially means converting values from one floating point format to another. However, it seems that almost every modern system is using IEEE754, so I'm wondering whether it's actually worth generalising to allow other formats, or just manage marshaling between different IEEE754 formats. Does anyone know of any commonly used floating point formats other than

问题 I am writing a marshaling layer to automatically convert values between different domains. When it comes to floating point values this potentially means converting values from one floating point format to another. However, it seems that almost every modern system is using IEEE754, so I'm wondering whether it's actually worth generalising to allow other formats, or just manage marshaling between different IEEE754 formats. Does anyone know of any commonly used floating point formats other than

问题 I am writing a marshaling layer to automatically convert values between different domains. When it comes to floating point values this potentially means converting values from one floating point format to another. However, it seems that almost every modern system is using IEEE754, so I'm wondering whether it's actually worth generalising to allow other formats, or just manage marshaling between different IEEE754 formats. Does anyone know of any commonly used floating point formats other than

问题 I need an associative data structure with floating point keys in which keys with nearly equal values are binned together. I'm working in C++ but language doesnt really matter. Basically my current strategy is to only handle single precision floating point numbers use an unordered_map with a custom key type define the hash function on the key type as a. given float v divide v by some tolerance, such as 0.0005, at double precision, yielding k . b. cast k to a 64 bit integer yielding ki c.

问题 I need an associative data structure with floating point keys in which keys with nearly equal values are binned together. I'm working in C++ but language doesnt really matter. Basically my current strategy is to only handle single precision floating point numbers use an unordered_map with a custom key type define the hash function on the key type as a. given float v divide v by some tolerance, such as 0.0005, at double precision, yielding k . b. cast k to a 64 bit integer yielding ki c.

问题 I want to read digit by digit the decimals of the sqrt of 5 in C. The square root of 5 is 2,23606797749979..., so this'd be the expected output: 2 3 6 0 6 7 9 7 7 ... I've found the following code: #include<stdio.h> void main() { int number; float temp, sqrt; printf("Provide the number: \n"); scanf("%d", &number); // store the half of the given number e.g from 256 => 128 sqrt = number / 2; temp = 0; // Iterate until sqrt is different of temp, that is updated on the loop while(sqrt != temp){ /