Im trying to get the current opengl verson.
glGetString(GL_VERSION) returns
"4.6.0 NVIDIA 391.01"
std::string strVersion = (const char*)glGetString(GL_VERSION);
strVersion = strVersion.substr(0, strVersion.find(" "));
float number = std::atof(strVersion.c_str());
float number = 4.59999990
why is the float not 4.6.0?
Why you don't get the third number
std::atof will take as many characters as it can that represent a decimal number. That's 4.6. The next dot cannot be part of the number, because there is no such thing as a decimal number with two dots. Decimal numbers only have one dot, separating the integer and the fractional parts.
Why you get 4.59999990 instead of 4.6
Because floating point numbers cannot store any possible combination of integer and fractional part. They have limited space to store information, so they always are just approximations. See is floating point math broken?.
How to get the version
A version is not a number. That version consists of three numbers, not one: 4, 6 and 0. They are integers, not decimal numbers. So you need to either just handle the version as a string:
if (strVersion == "4.6.0")
or you have to split it into three parts and get those integer values separately. See Splitting a C++ std::string using tokens for how to do that.
Related
I have a range of values and I want to count the decimal points of all values in the range and display the max count. the formula should exclude the zeroes at the end(not count ending zeroes in the decimal points).
for example, in the above sample, in the whole range the max of count of decimal places is 4 excluding the ending zeroes. so the answer is 4 to be displayed in cell D2
I tried doing regex, but do not know how do I do it for a whole range of values.
Please help!
try:
=INDEX(MAX(LEN(IFERROR(REGEXEXTRACT(TO_TEXT(A2:C4), "(\..+)")*1))-2))
Player0's solution is a good start, but uses TO_TEXT which seems to rely on the formatting of your cells.
If you want to safely compute the number of decimal places, use the TEXT function instead.
TEXT(number, format) requires a format whose max. number of decimal places has to be specified. There is no way around this, because formulas like =1/3 can have infinitely many decimal places.
Therefore, first decide on the max, precision for your use-case (here we use 8). Then use below function which works independently from your document's formatting and language:
=INDEX(MAX(
LEN(REGEXEXTRACT(
TEXT(ABS(A2:C4); "."&REPT("#";8));
"[,.].*$"
))-1
))
We subtract -1 since LEN(REGEXEXTRACT()) also counts the decimal separator (. for english, , for many others) .
Everything after the 8th decimal place is ignored. If all your numbers are something like 123.00000000987 the computed max. is 0. If you prefer it to be 8 instead, then add ROUNDUP( ; 8):
=INDEX(MAX(
LEN(REGEXEXTRACT(
TEXT(ROUNDUP(ABS(A2:C4);8); "."&REPT("#";8));
"[,.].*$"
))-1
))
I am building a neural network and using xtensor for array multiplication in feed forward. The network takes in xt::xarray<double> and outputs a decimal number between 0 and 1. I have been given a sheet for expected output. when i compare my output with the provided sheet, I found that all the results differ after exactly 7 digits. for example if the required value is 0.1234567890123456, I am getting values like 0.1234567-garbage-numbers-so-that-total-numbers-equal-16, 0.1234567993344660, 0.1234567221155667.
I know I can not get that exact number 0.1234567890123456 due to floating point math. But how can I debug/ increase precision to be close to that required number. thanks
Update:
xt::xarray<double> Layer::call(xt::xarray<double> input)
{
return xt::linalg::dot(input, this->weight) + this->bias;
}
for code I am simply calling this call method a bunch of times where weight and bias are xt::xarray<double> arrays.
I have data in a spreadsheet describing amount of data transferred over a mobile network: data in one column (over 300 rows) has three possible forms:
123,45KB
123,45MB
1,23GB
How can I transform or use this data in order to sum or do other calculations on numbers properly?
Assuming your data is in column A and there are always two characters as unit ("KB", "MB" or "GB") at the end, then the formula for transforming the data to numeric could be:
=--LEFT(A2;LEN(A2)-2)*10^(IF(RIGHT(A2;2)="KB";3;IF(RIGHT(A2;2)="MB";6;IF(RIGHT(A2;2)="GB";9))))
Result:
Put the formula in B2 and fill downwards as needed.
I suspected the decimal delimiter in your locale is comma. If not, please state what it is.
Also since this site is English, I have used English function names. Maybe you need to translate them into your language version.
If the decimal delimiter in your locale is not comma, then you need substituting the comma with your decimal delimiter to get a proper numeric decimal value.
For example if the decimal delimiter is dot, then:
=SUBSTITUTE(LEFT(A2,LEN(A2)-2),",",".")*10^(IF(RIGHT(A2,2)="KB",3,IF(RIGHT(A2,2)="MB",6,IF(RIGHT(A2,2)="GB",9))))
An alternative formula:
=LEFT(A1,LEN(A1)-2)*10^(3*MATCH(RIGHT(LEFT(A1,LEN(A1)-1)),{"K","M","G"},0))
Uses the position of the next to last character in an array to determine the factor.
I am trying to convert a column stored from character to numeric. The problem is that this column has varying number of decimal places.
For example,
Data
1052969525
392282764.234
221018301.2
130010764.7894
82340150
183779233.4
I have determined that the likely maximum of decimal places is 4, the width required would be about 15. So I have attempted the following:
datanum = input(data, 15.4);
But this appears to put the decimal place in the wrong place, especially for those that have no decimal places. What is the most reasonable way to convert this column from char to numeric? This column is part of a database table uploaded by someone else so there's not much option to change that. Thanks.
You don't normally supply the decimal width in informats. For a normal number, you only supply the width, and SAS will figure out the decimal for you (based on the position of the decimal point).
datanum = input(data,15.);
The .d part of an informat is to allow for compatibility with (mostly) older systems that did not have decimals in the data, to save space. For example, if I'm reading in money amounts, and I only have 6 spaces:
123456
882348
100000
123400
I can read that in as an integer amount of cents - or I can do:
input cost 6.2;
That will then tell SAS to place the decimal before the last 2 characters.
I want an input field with a decimal number upto 2 decimals after the point.
I am using
^\d+\.\d{0,2}$
which works just fine with any 2 decimal number after the point but it does not consider two zeros i.e. 2.00.
How can I include 2.11 and as well as 2.00?