hello all, i have 3 questions to bother you with.
1) what is the motivation behind using the recurrence relation for the computation of the mean ? seems to me that a division by the number of elements *after* the for loop will result in fewer division operations than the current implementation. i have noticed the use of recurrence type computation of variance as well. 2) many functions have a return type of double but the quantity of interest that is to be returned is declared as a long double inside the function body. why is this done? is it that conversion from a long double to double results in less loss of precision? 3) declaration of variables inside the for loop body e.g. delta in the following snippet from variance_source.c /* find the sum of the squares */ for (i = 0; i < n; i++) { const long double delta = (data[i * stride] - mean); variance += (delta * delta - variance) / (i + 1); } does the compiler keep creating a local delta each time control enters the loop or is it created once but treated as a local variable and valid only in the scope of the for loop? _______________________________________________ Help-gsl mailing list Help-gsl@gnu.org https://lists.gnu.org/mailman/listinfo/help-gsl