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How do I represent extremely large or small numbers in C with a certain amount of significant figures. For example, if I want to do calculations on 1.54334E-34, how could I do this. Also, is this applicable to OpenCL code?
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Because it can be hard to type or display exponents in C++, we use the letter 'e' (or sometimes 'E') to represent the “times 10 to the power of” part of the equation. For example, 1.2 x 10⁴ would be written as 1.2e4 , and 5.9736 x 10²⁴ would be written as 5.9736e24 .
%g. It is used to print the decimal floating-point values, and it uses the fixed precision, i.e., the value after the decimal in input would be exactly the same as the value in the output.
For scientific notation, you can type either a caret (^) or the letter e followed by a number to indicate an exponent. You can use both positive and negative exponents. For example, to indicate 0.012 , you can enter either of the following expressions: 1.2*10^-2.
float var = 1.54334E-34;
double var2 = 1.54334E-34;
printf("\n normal:%f\n sci:%e \n or \n sci:%E \n",var,var,var);
printf("\n normal:%f\n sci:%e \n or \n sci:%E \n",var2,var2* 1.0E3 ,var2 * 1.0e3);
I don't know any OpenCL but 32-bit C floats will hold values in the range of +/- 3.4e +/- 38 (~7 digits), and doubles much more. If you want arbitrary precision arithmetic/math you may want to look into GMP or MPFR.
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